SLOUGH BOROUGH COUNCIL

LOCAL IMPACT REPORTS

HIGHWAYS ENGLAND'S RESPONSE

1. INTRODUCTION

1.1 This Local Impact Report sets out the preliminary position of Slough Borough Council (SBC) in relation to the issues of concern in the Borough arising from the M4 Smart Motorway Scheme (referred to as ‘the Scheme’). The report also responds to the First Written Questions of the Examining Authority (ExA) where relevant to Slough.

1.2 Slough is a compact densely built-up Borough with a population of some 143,000. The M4 fringes the southern edge of the town and runs approximately parallel to the A4, the historic route between London and Bath. Three motorway junctions serve Slough:

(a) Junction 7 linking with the A4 via the Huntercombe Spur;

(b) Junction 6 linking with the A355 which connects southwards with Windsor and northwards with Slough Trading Estate, South Buckinghamshire and the M40; and

(c) Junction 5, the Langley Interchange, linking with the A4 and giving access to Heathrow and Slough town centre.

1.3 Between Junctions 7 and 6 the M4 runs close to residential areas and public open space at Cippenham. East of Junction 6 the motorway fringes residential areas and school grounds at Chalvey and Herschel Park. East of Junction 5 it severs the built up area, with Langley to the north and Brands Hill to the south. Air quality, noise and visual amenity are major concerns and Slough Borough Council (SBC) is anxious to protect its residents and others from negative impacts arising from the Smart Motorway scheme.

1.4 Because of its proximity to London, Heathrow and the M25, and being home to the extensive Slough Trading Estate, the Borough experiences high levels of traffic. Traffic leaving or joining the M4 at Slough regularly causes queuing and congestion on the local road network during peak periods. Occasionally, heavy congestion or an incident on the M4 can bring traffic in Slough to a virtual standstill as drivers divert off the motorway. SBC notes from the Socio-Economic Report (2.1.1 APP- 090) that the M4 typically carries over 130,000 vehicles per day and that this is forecast to increase to an average 160,000 vehicles per day over the next 20 years. Unless properly managed, this additional traffic could significantly increase pressures on the local road network.

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Highways England's Comment

1.4.1 Highways England notes Slough Borough Council’s concerns in respect of air quality, noise and visual amenity and the effects of the Scheme on its residents. Detailed responses to these issues are given under the respective sections below and demonstrate that there are no material adverse effects arising from the Scheme.

1.4.2 Highways England confirms that the M4 typically carries 130,000 vehicles a day and that it is expected that this will rise to an average 160,000 vehicles a day. This is the increase in traffic forecast to arise without the Scheme and is a reflection of national economic growth in general and the Thames Valley in particular. Highways England considers that the Scheme will play a major role in managing future traffic conditions in conjunction with the local authorities through their respective Local Transport Plans.

2. POLICY

National Policy Statement for National Networks (NNNPS)

2.1 SBC takes particular note of those sections of the NNNPS that require HE to provide evidence that they have considered ‘reasonable opportunities to deliver environmental and social benefits’ as part of the Scheme (NPS para 3.3); and ‘use reasonable endeavours to address the needs of cyclists and pedestrians in the design of new schemes’ (NPS para. 3.17).

Highways England's Comment

2.1.1 The opportunities provided by the Scheme to deliver environmental and social benefits have been considered by Highways England. The Socio-Economic Report (Application Document Reference 7-2) refers to a range of beneficial effects to be derived from construction of the Scheme (Paragraph 7.1.4), whilst Paragraph 7.1.6 of the Report highlights a number of mitigation measures proposed to ameliorate negative effects of the Scheme. The Engineering and Design Report (Application Document Reference 7-3) refers, in Paragraph 7.12.1 to various enhancement measures set-out in the accompanying Environmental Masterplan (Annex F to the Report), as suggested mitigation measures for the Scheme.

2.1.2 Chapter 13 (Effects on all Travellers) of the Environmental Statement (Application Document Reference 6-1) assessed the potential effects of the Scheme on vehicle travellers and non-motorised users (NMUs). The latter group includes pedestrians, cyclists, and equestrians. Paragraph 13.1.3 of the

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ES notes that NMUs are not permitted to use motorways for safety reasons, although it recognises that they may be affected by the Scheme when travelling on the locally adopted highway network and other Public Rights of Way (“PRoW”) surrounding or interacting with the Scheme.

2.1.3 The assessment undertaken within the Chapter focussed on the Scheme effects on pedestrians, cyclists, equestrians in relation to the impacts on PRoW. Paragraph 13.6.1 advises that proposed mitigation measures for NMUs during the Scheme’s construction phase will be managed and monitored pursuant to the CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3), which is secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

Slough Local Plan

2.2 SBC confirms that Table 1 of APP-089 accurately identifies the Development Plan for Slough, i.e.

(a) Slough Borough Council Local Plan (March 2004);

(b) Saved Policies (September 2007);

(c) Core Strategy;

(d) Development Plan Document 2006-2026 (December 2008).

2.3 The Highways England (HE) Planning Statement refers to Core Policy 7 and SBC draws attention to the following wording: ‘Development proposals will, either individually or collectively, have to make appropriate provisions for.... improving air quality and reducing the impact of travel upon the environment, in particular climate change.’

2.4 SBC also draws attention to Core Policy 8 which includes the wording: ‘Development shall not: a) Give rise to unacceptable levels of pollution including air pollution, dust, odour, artificial lighting or noise’.

2.5 Reference is correctly made in the HE Planning Statement (6-49) to the ‘Action Plan for Slough Air Quality Management Areas Nos. 3 and 4’, November 2012. However SBC wishes to make clear that the Action Plans for Air Quality Management Areas no. 1 (M4 corridor) and no. 2 (Brands Hill) were included in ‘Annex C of the Second Local Transport Plan, March 2006’ which superseded the provisional document of July 2005 referred to in 6-48. Furthermore, these action plans were revised and specific measures incorporated into the ‘Slough’s Third Local Transport Plan 2011- 2026’ (para 5.6.4.): see 2.8 below.

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Highways England's Comment

2.5.1 The provisional Air Quality Action Plans referred to within Appendix 6.5 of the ES (Application Document Reference 6-3) were replaced by ‘Annex C of the Second Local Transport Plan, March 2006’ and that this has subsequently been superseded by Slough’s Third Local Transport Plan 2011- 2026 (“LTP3”).

2.5.2 The LTP3, and in particular paragraph 5.6.4, has been reviewed. Paragraph 5.6.4 notes

that to reduce levels of nitrogen dioxide (“NO2”) the following is necessary:

 “Reduce the number of vehicles on the road;

 Reduce the levels of emissions from vehicles per mile; and

 Reduce stop/start traffic conditions.”

2.5.3 The LTP3 notes, in paragraph 5.6.7, that sustainable land use planning policies will be key to achieving reductions in the numbers of vehicles on the road (i.e. bullet point 1 above). Paragraph 5.6.7 of LTP3 cross references key policies within the Local Development Framework ("LDF") concerning sustainable land use and air quality. The Scheme does not adversely impact upon any of the LDF policies identified in paragraph 5.6.7.

2.5.4 Other actions to reduce the number of vehicles on the road contained within LTP3 include managing “parking demand” (paragraph 5.6.14), “school and workplace travel plans” (paragraphs 5.6.15-5.6.16 and 5.6.20-5.6.21), and promoting walking and cycling (5.6.17-5.6.19). The Scheme does not adversely impact upon any of the LDF policies identified in the above paragraphs.

2.5.5 Reductions in levels of emissions from vehicles per mile is considered within LTP3 for “cleaner buses, taxis and commercial vehicles” (paragraphs 5.6.11-5.6.12) and “promoting less polluting travel” (paragraph 5.6.13). The Scheme does not adversely impact upon any of the LDF policies identified in paragraphs 5.6.11-5.6.13.

2.5.6 The LTP3 discusses better management of congestion and speed in paragraphs 5.6.8- 5.6.10. In paragraph 5.6.10, the A4 and junction 5 of the M4 is discussed and opportunities to work with the Highways Agency (now Highways England) concerning the junction and mainline M4 are identified. The implementation of the Scheme may assist in the management of traffic both at junction 5 and the mainline of the M4.

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2.6 SBC’s comments on HE’s assessment of the project against these Core Strategy policies (APP- 089) are as follows:

(a) Ref Planning Statement 5.4.25: summary description of proposals in Slough area is acknowledged but it excludes reference to construction compounds near Junctions 6 and 7;

(b) 5.4.26: SBC agrees that ‘very special circumstances’ apply in relation to Green Belt but not necessarily in the case of the proposed Construction Compounds (see 2.10 below);

(c) 5.4.27: SBC accepts that there would be no significant detrimental effect on nature conservation interests or watercourses and the floodplain; in relation to archaeology and landscaping, SBC accepts that mitigation measures and enhancement measures are proposed but not that they would satisfactorily comply with the policy requirements;

Highways England's Comment

2.6.1 A response to each of the comments made in Paragraph 2.6 is provided below:

(a) The construction compounds were not included in the summary for Slough, which refers to the main line works. Construction Compound 7 at Junction 6 is located immediately to the south of Slough's administrative boundary within the Royal Borough of Windsor and Maidenhead. Construction Compound 6 at Junction 7 is located to the west of Slough's administrative boundary with South Bucks District Council.

(b) Highways England responds substantively to this point in response to Paragraph 2.11 below, but notes here that Paragraph 5.2.162 of the Planning Statement (Application Document Reference 7-1) states that the use of the construction compounds will be temporary, and that the land will be reinstated after any use. The nature of the Scheme is such that there is a requirement for the supporting infrastructure to be located near to the main works on a practical and an environmental basis.

(c) Highways England disagrees that the mitigation measures proposed would not comply with the requirements of Policy EN3 (Landscaping Requirements) of the Adopted Local Plan.

Policy EN3 requires comprehensive landscaping schemes to be prepared for all new development proposals and includes for the retention of existing vegetation to be included as part of the landscape proposals. The response to Policy EN3 within Appendix 1 of the Planning Statement (Application Document Reference 7-1) refers to the environmental masterplan which provides the proposed approach to environmental design. This document reflects the preliminary design stage of the

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Scheme at the time of the Application and includes comprehensive landscape proposals to mitigate the effects of the Scheme. The landscape proposals were prepared following the principles and guidance set out in the Design Manual for Roads and Bridges Volume 10 and indicate the relevant environmental functions and landscape elements which are proposed to achieve the necessary mitigation. On this basis, it is considered that the landscape proposals do comply with Policy EN3. A detailed landscape design for the Scheme will be developed from the environmental masterplan pursuant to Requirement 9, Schedule 2 of the Draft DCO (Application Document Reference 3-1), which states amongst other matters, that the authorised development must be landscaped in accordance with a landscaping scheme to be approved by the local planning authority.

Policy EN20 of the Adopted Local Plan requires that in areas with archaeological potential, an archaeological field evaluation is to be carried out before any decision on a planning application. Notwithstanding the fact that the Application is an application for development consent, and not a planning application, paragraphs 7.8.1 to 7.8.8 of the Environmental Statement (Application Document Reference 6- 1) detail known heritage assets within the vicinity of Junctions 8/9 (within the Borough) as a result of previous archaeological research investigations and highlights the known archaeological remains within the vicinity of construction compound 5. On the basis of the assessment work undertaken, Requirement 15, Schedule 2 of the Draft DCO (Application Document Reference 3-1) requires, amongst other matters, the investigation and recording of archaeological remains not previously identified, to the local authority. Requirement 16 is included specifically in relation to construction compound 5 and requires a programme of archaeological work, including a written scheme of investigation, to be submitted to, and approved by, the local authority before work commences.

2.7 SBC confirms that there are no other developments which are either proposed in or in accordance with the Local Plan which might be affected by the project. However there are other strategic infrastructure schemes proposed in the vicinity of Slough and the potential cumulative effect of these should be taken into account: see 8.1-8.3.

Highways England's Comment

2.7.1 Highways England responds to the reference to the potential cumulative effect of other infrastructure developments in the responses to paragraphs 8.1 to 8.3 below.

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Slough Local Transport Plan

2.8 SBC confirms that Table 1 of APP-089 accurately identifies the Local Transport Plan (LTP) for Slough, i.e. the Slough’s Third Local Transport Plan 2011- 2026. However no reference is made to the Supplementary Strategy Documents (SSD) that give further details on Slough’s local transport strategy. Of particular relevance are those relating to network management and Intelligent Transport Systems (ITS).

Highways England's Comment

2.8.1 Highways England notes SBC’s Supplementary Strategy Document on Network Management and Intelligent Transport Systems.. and, in particular, NMD Theme 1: “Managing Network Efficiency, Demand and Future Growth”. This theme recognises (paragraph 2.3.2 of the SSD) the M4 as part of SBC’s Strategic Route Network with its focus on the movement of people and goods. The Scheme will be particularly supportive of SBC’s desire to retain its economic competitiveness and role as an economic hub in the South East.

2.8.2 Highways England also notes Strand 4 of the Council’s policies within Theme 1 (paragraph 3.1.1.4 of the SSD) covering “Managing the Road Network more efficiently”, with its emphasis on ITS and the use of technology. SBC’s UTC (Urban Traffic Control), VMS (Variable Message Signs), air quality monitoring, real time passenger information and journey time monitoring systems are complementary to the implementation of traffic control technology within the Scheme. The Council’s aspiration to move towards UTMC (Urban Traffic Management and Control) is also complementary to the continuation of partnership working with Highways England under the SSD’s NMD Theme 3: “Contingency Planning and Incident Management” (paragraph 3.3.3 of the SSD) which has formalised agreed routes and junctions to be used to direct motorists on and off the motorway in the event of a major incident.

2.9 SBC’s comments on HE’s assessment of the project against the policy guidance set out in the LTP are as follows:

(a) 5.4.28: SBC accepts that the Scheme is in generally alignment with the LTP framework but does not agree that overall changes in air quality would be insignificant nor that noise impacts would be negligible;

(b) SBC does not consider that the Scheme would directly contribute to LTP strategies aimed at increasing the uptake and mode share for public transport, walking and cycling (reflecting

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NNNPS para.3.17) but it is recognised that there are opportunities open to HE to assist in delivery of these strategies, i.e.

(i) Partnership working to provide bus priorities at Junction 5 Langley Interchange A4 roundabout for SBC’s SMaRT bus rapid transit scheme to link Slough and Heathrow (see 8-4,8.5);

(ii) Further improvements for pedestrians and cyclists in relation to Junction 5 Langley Interchange;

(iii) Recreation Bridge: improvements to National Cycle Network Route 61;

(iv) Old Slade overbridge: bridleway provision for Colne Valley Trail;

(v) Wood Lane overbridge: improvements for pedestrians and cyclists; and

(vi) Enhancement of routes required for rights of way diversions.

Highways England's Comment

2.9.2 Highways England is confident that the overall changes in air quality are not significant, and that the noise impacts would be minor beneficial in the short term and negligible in the long term. SBC has not explained what evidence is has which causes it to challenge Highways England's assessment of air quality or noise impacts.

2.9.3 In relation to air quality, the evidence that the overall changes in air quality would be insignificant is contained in the Air Quality assessment for the Scheme, which is provided in Chapter 6 of the ES (Application Document Reference 6-1).

2.9.4 Paragraphs 6.9.15, 6.9.16, 6.10.17, 6.10.18, 6.10.19, 6.11.14 and 6.11.15 of the ES (Application Document Reference 6-1) identify the predicted air quality effects of the Scheme on the 382 sensitive receptors located with the Slough Borough Council administrative area that were explicitly modelled in the air quality assessment. These receptors are also shown on Drawings 6.11, 6.12 and 6.13 and associated insets (Application Document Reference 6-2). The predicted changes at these receptors are imperceptible (0.4 µg/m3 or less) to small (>0.4-2.0 µg/m3) increases in annual mean

nitrogen dioxide (“NO2”). In total 11 small increases in annual mean NO2 are predicted within Slough with the Scheme at receptors also predicted to experience annual mean concentrations above the air quality objective (40 µg/m3).

2.9.5 The assessment of significant effects on air quality is determined following the methodology set out in Interim Advice Note 174/13 “Updated advice for evaluating significant local air quality effects for users of DMRB Volume 11, Section 3, Part 1 ‘Air

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Quality’ (HA207/07)”, which is considered to be a suitable methodology for determining significance for air quality for a highways scheme.

2.9.6 On the basis of this approach, the Scheme is not predicted to result in significant air quality effects, and as such specific air quality mitigation measures are not required.

2.9.7 In relation to noise impacts, the evidence that the overall changes in noise levels would be minor beneficial in the short term and negligible in the long term is contained in the Noise and Vibration assessment for the Scheme, which is provided in Chapter 12 of the ES (Application Document Reference 6-1). The overall operational assessment of significance of the Scheme is set out in paragraph 12.4.110 of the ES (Application Document Reference 6-1).

2.9.8 Highways England agrees that the Scheme will not directly contribute to LTP strategies aimed at increasing the uptake and mode share for public transport, walking and cycling except for those opportunities emanating from the reconstruction/replacement of crossing facilities that serve NMUs, such as upgrading parapets on bridleways for the safe passage of equestrians. This is in compliance with NN NPS paragraph 3.17.

2.9.9 However, whilst the Scheme is a motorway and cannot contribute directly to LTP strategies on NMUs, the wider benefits arising from the transfer of traffic from less suitable routes will provide opportunities for the amenity of NMUs to be enhanced within local communities.

2.9.10 In relation to the specific physical measures identified in point 2.9, the Scheme is not intended, designed or required to improved transport provision or the facilities available to NMUs. However, it will be noted from [what?] that where re-provision is made, it represents a marginal improvement on the status quo ante.

2.10 An important part of the Slough LTP strategy is to influence travel behaviour through a ‘smarter choices’ programme which promotes sustainable transport as an alternative to private car use; there is no reference in the Socio-economic Report to these aspects of the LTP3 and the effect on mode shift . As the result of Government support through the Local Sustainable Transport Fund (LSTF) SBC has been actively implementing this programme for the last three years and additional LSTF funding is in place to extend the programme until March 2016. The DCO application for the Scheme offers the opportunity to extend the programme further as a ‘smarter choices package’ that would complement the Smart Motorway project and help deliver the environmental and social benefits foreseen in the NNNPS as touched on in 2.1 above.

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Highways England's Comment

2.10.1 The Socio-Economic Report (Application Document Reference 7-2) makes reference to the Slough Borough Council Core Strategy 2006 – 2026 in Appendix A with particular reference to SBC's strategic objective E which encourages investment and regeneration. As with other local authority strategies referenced in the Socio-Economic Report, only high-level core strategies (or equivalent) have been cited. It is acknowledged they will be supported by topic-specific policies and initiatives. For this reason, the 'smarter choices' programme has not been explicitly considered by the Scheme.

2.10.2 Whilst modal shift is not addressed in the Socio-economic Report in relation to SBC's LTP3, modal shift more generally has been addressed by Highways England by the use of a variable demand model in its approach to forecasting, by assessing a scenario with public transport schemes contained within but excluding the Scheme to demonstrate public transport alone would not resolve the congestion issues on the M4 and, finally, by checking and confirming that the Scheme does not have a detrimental impact on mode share. Sustainable transport interests will be protected by Highways England in its consideration of maintaining community links for NMUs provided by the various crossing facilities.

2.10.3 Highways England acknowledges the Slough LTP strategy to influence behaviour and, as stated in paragraph 2.9.5 above, considers the Scheme will improve the management of road space on the M4 alongside and not in conflict with local transport strategies.

2.10.4 Highways England does not consider that the Scheme should extend SBC's smart choices programme. The Scheme is a motorway project which is intended to increase capacity on the mainline M4. Where social and economic impacts have been identified in the Socio-economic Report, suitable mitigation has been provided. As noted in Highways England's responses above, the Scheme will deliver wider social and environmental benefits in compliance with the NN NPS.

Green Belt

2.11 The M4 lies in the Green Belt for most of its route through the Borough. SBC accepts that the proposed operations and gantries would not have a material impact on the openness of the Green Belt nor on the 5 purposes of that designation. However it is considered that the proposed construction compounds would, bearing in mind the uncertainties surrounding the number actually needed; the location of the

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main office; and their duration (potentially for the whole of the 5-year construction period), would be inappropriate development and are likely to affect the openness of the Green Belt.

Highways England's Comment

2.11.1 Highways England disagrees that the proposed construction compounds represent inappropriate development, and considers that they will not affect the openness of the Green Belt. Paragraphs 5.2.156 to 5.2.174 of the Planning Statement (Application Document Reference 7-1) consider the compliance of the proposed development with the aims of Green Belt policy referred to in Paragraph 5.164 of NN NPS. Reference is also made to the compliance of the proposed development with the policy framework provided by the NPPF in paragraph 5.2.213.

2.11.2 The Planning Statement makes clear that the use of these compounds will be temporary, and the land will be reinstated at the end of the construction period. For these reasons, Paragraph 5.2.162 concludes that the proposed development represents appropriate development in the Green Belt, in compliance with the policy framework provided by NN NPS and NPPF.

3. ENVIRONMENT

Landscape and visual impact

Operational Scheme

3.1 SBC accepts the baseline information for HE’s landscape and visual assessment. The viewpoints put forward by the HE in February 2015 (APP-148 para 8.2.8) as representative of available were accepted by SBC on the basis that the HE would provide a more detailed assessment of the visual impact of the proposed new bridges. HE did suggest that further photomontages might be prepared once the DCO application had been submitted: SBC notes those provided in APP-300 but is not certain whether any additional photomontages have been produced.

Highways England's Comment

3.1.1 SBC were contacted via e-mail on 11 February 2015 regarding the viewpoint locations presented in the Preliminary Environmental Information Report. SBC’s responded that the viewpoints were acceptable but noted that they presumed that they would receive a more detailed visual assessment of the impact of the proposed new bridges.

3.1.2 No further request from SBC for additional photomontages was received. In regard to the last point raised by Slough, the visual assessment contained in

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Chapter 8 of the ES considered the proposed new bridges. Further detail is provided in the response to paragraph 3.4 below.

3.1.3 Highways England can confirm that additional photomontages, post Application have been prepared in relation to the Cranford Park area and the Harlington Conservation Area to the west of the M4 junction 3. No further photomontages within the area of Slough have been prepared since the Application was submitted.

3.2 The Scheme would inevitably have a visual impact on the Borough, especially in relation to new bridges and other structures; removal of vegetation for widening; installation of gantries, noise barriers and lighting; and construction compounds. SBC agrees with the Examining Authority (ExA) that it is not clear how the HE defines ‘significant’ in relation to the visual impact of the Scheme (APP- 148). There are also uncertainties, as pointed out in the ExA’s questions, about the dimensions of the proposed gantries; the dimensions, materials, colour and location of environmental (noise) barriers; and the design of new lighting.

Highways England's Comment

3.2.1 The impact of the Scheme on landscape and visual impacts on receptors within SBC's jurisdiction is discussed in Chapter 8, sections 8.9 and 8.11 and in Table 8.3 for junctions 7 to 6 and junctions 5 to 4b in the ES (Application Document Reference 6-1). The results of the visual effects assessment on receptors are illustrated in Drawing 8.2, with Sheets 10, 11, 13 and 14 relating to Slough Borough Council’s jurisdiction (Application Document Reference 6-2) and in Appendix 8.3 of the ES in the Visual Effects Tables (Application Document Reference 6-3). These show that the typical residual visual impacts would initially be moderate adverse reducing by Design Year 15 to slight adverse as the landscape mitigation establishes. However, at one location it is not be possible to mitigate the effects of the Scheme resulting in a residual moderate adverse effect.

3.2.2 In relation to the definition of "significant" in visual impact terms, the Guidelines for Landscape and Visual Impact Assessment do not require an assessment of significance or significance thresholds, nor is this required by Interim Advice Note 135/10. Thresholds stated in paragraph 8.2.16 of the ES (Application Document Reference 6-1) are a matter of professional judgement, informed by the criteria set out in IAN 135/10 and DMRB Volume 11, Section 2, Part 5. The latter document indicates that ‘large’ or ‘very large’ effects are likely to be material in the decision making process - it is the effects that fall within these categories that are likely to be significant in EIA terms.

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3.2.3 Highways England does not consider that there are uncertainties in the visual impact of the Scheme. In relation to the dimensions of the proposed gantries which are provided in the Application Plans Gantry General Arrangements (Application Document Reference 2-8). The Engineering and Design Report (“EDR”) (Application Document Reference 7-3) contains descriptions of the various gantry types and is incorporated by reference at paragraph 4.1.3 of the ES (Application Document Reference 6-1). The EDR describes the gantry types at Section 6.4. The ES illustrates gantry types in Drawings 4.1 and 4.2 and their locations are illustrated on each of the Environmental Masterplan Sheets 20 to 27 .

3.2.4 In relation to the dimensions (length and height) of the proposed new environmental noise barriers which are provided in Appendix 12.2 of the ES (Application Document Reference 6-3) and illustrated on Sheets 20 to 27 of the Environmental Masterplan (Annex A1 of the Engineering and Design Report) (Application Document Reference 7-4). The visual assessment assumed that the new or replacement environmental barriers would be of timber construction and be of similar appearance and weathering properties to the existing environmental / noise barriers. This is the usual choice for environmental noise barriers that take the form of a fence on highway schemes.

3.2.5 The lighting proposals are described in paragraph 4.2.4(c) of the ES (Application Document Reference 6-1) and in paragraph 6.3.44 of the Engineering and Design Report (Application Document Reference 7-3). As described in paragraph 6.3.44 of the EDR, highway lighting would comprise modern light emitting diode (“LED”) lighting with a central management control system.

3.3 SBC notes the landscaping proposals put forward in the Environmental Master Plan (APP- 351) but on present evidence is not satisfied that these would provide the necessary mitigation in winter as well as summer conditions. In the Planning Statement (APP-089, 5.2.18) it is suggested that ‘opportunities for environmental enhancement measures have been taken where possible’. SBC considers that there are further enhancement opportunities that should be taken.

Highways England's Comment

3.3.1 Highways England disagrees that there are further enhancements which should be taken by the Scheme. The landscape mitigation strategy for the Scheme comprises the provision of planting to replace the existing vegetation lost to the Scheme during the construction, where possible. The vegetation clearance and mitigation proposals are provided in the Engineering and Design Report, Annex A2, Vegetation Clearance and

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Annex A1, Environmental Masterplan (Application Document Reference 7-4). There are not anticipated to be significant residual landscape and visual effects at Design Year (2037) (15 years after construction) due to establishment of planting. SBC has not provided evidence of where further enhancement opportunities might be taken, and Highways England has not identified any further locations within the Order Limits where further enhancement opportunities can be provided.

3.4 In terms of structures SBC is particularly concerned about the visual impact of:

(a) Huntercombe eastern realignment of slip road (views from nearby housing, Mercian Way Recreation Ground and allotments);

(b) Oldway Lane overbridge (views from nearby housing and Mercian Way Recreation Ground; new bridge 1.1m higher than at present);

(c) Wood Lane overbridge, noise barrier to the west and retaining wall to east (views from nearby housing and public open space; new bridge 1.4m higher than at present);

(d) Junction 6 slip road realignments (impact on existing vegetation);

(e) Datchet Road overbridge (view from Upton Court Park direction; loss of trees through realignment of highway); and

(f) Junction 5 Langley Interchange widening (prominent feature viewed from both north and south with significant disturbance to existing tree and shrub screening; new piers, embankments and retaining walls).

Highways England's Comment

3.4.2 The purpose of the landscape and visual assessment contained in Chapter 8 of the ES is to identify and report the main effects of the Scheme. The preparation of the ES was initially based on the information contained in the Preliminary Environmental Information Report (“PEIR”) (Issued November 2014) which sets out locations where potential visual effects may arise. Chapter 8 of the ES takes account of the Scheme development since the submission of the PEIR. The ES focusses on reporting areas where visual effects are expected, which means that some not significant effects have not been explicitly reported, although all potential effects have been assessed. The potential visual effects of the structures raised in the representation of SBC are each considered in turn below.

3.4.3 The visual effects of the Huntercombe Spur realignment are illustrated on Drawing 8.2 Sheet 10 and described in Appendix 8.3 of the ES. It is accepted that there will be some

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visual effects in this location. It will be noted that this is frequently the case, and it is for this reason that representative visual assessments are carried out. The nearest visual receptor in this case is 10.1.15 which will experience a slight adverse significance of effect.

3.4.4 Dealing with the specific analysis that would apply for the allotments, a number of factors need to be borne in mind. These include the sensitivity, in respect of which: users of the allotments are of medium sensitivity) and residential properties are of high sensitivity on Westpoint, which have varying types of view to the Huntercombe Spur beyond a line varying height. The views have a relatively dense line of existing vegetation, which runs along the west side of the allotments in question. Although the vegetation would be retained, the construction work associated with the Huntercombe Spur realignment would remove the existing scrubby vegetation with the occasional tree on the embankment between the eastbound on slip and the westbound on slip (Engineering and Design Report (“EDR”) Annex A2, Vegetation Clearance, Sheets 20). The lost vegetation forms part of the back drop to the view, and also helps to partially filter views to the traffic on the embankment during the summer when the vegetation is in leaf. The construction work associated with the Huntercombe Spur realignment and the transient traffic on the elevated slip road would be perceptible, particularly in upper storey views from the residential properties and the view would experience a minor change. It is anticipated that the existing retained vegetation which runs between the allotments and the eastbound on slip will help to screen / filter views during the summer and winter months from the ground storey and from the allotments. However, some aspects of the construction would be perceptible and have a minor magnitude of change on these locations. It is therefore concluded that, at worst, the construction would result in some minor adverse visual effects.

3.4.5 The visual effects of the proposed Oldway Lane Accommodation overbridge, which takes account of the additional 1.1m high parapet are illustrated on Drawing 8.2 Sheet 10 and described in Appendix 8.3 of the ES. It is reported that the nearby residential properties on Mercian Way and Two Mile Drive would experience slight adverse effects during construction and at Design Year 2022, but by Design Year 2037 the residual effects would be neutral. The users of the Mercian Way Recreation Ground would experience moderate adverse effects during construction and at Design Year 2022, but by Design Year 2037 the residual effects would be neutral.

3.4.6 The visual effects of the Wood Lane overbridge, which takes account of the additional 1.4m high parapet and the noise barrier to the west are illustrated on Drawing 8.2 Sheet 11 and described in Appendix 8.3 and in paragraph 8.9.13 item b) of the ES. It is reported that the nearby residential properties on Wood Lane would experience a moderate

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adverse effect during construction and a slight adverse visual effect at Design Year 2022, but by Design Year 2037 the residual effects would be neutral due to the establishment of the planting (see Annex A1, Environmental Masterplan, Sheet 21 (Application Document Reference 7-4). The residential properties users at Haswell Crescent would experience a slight adverse visual effect during construction and at Design Year, but by Design Year 2037 the residual effects would be neutral. The visual effects on the recently laid out public space to the north west of the Wood Lane overbridge would experience a moderate adverse effect during construction and a slight adverse visual effect at Design Year 2022, but by Design Year 2037 the residual effects would be neutral due to the establishment of the planting (see Annex A1, Environmental Masterplan, Sheet 21 (Application Document Reference 7-4). The proposed retaining wall at the toe of the north east approach embankment to the Overbridge would form a very minor structure in views from the adjacent open space and which over time would be obscured by the proposed planting.

3.4.7 The visual effects of the Junction 6 slip road realignments are illustrated on Drawing 8.2 Sheet 11 and described in Appendix 8.3 and in paragraph 8.10.15 item a) of the ES. It is reported that the nearby residential properties on Spackman Way to the north east of the M4 Junction 6 would experience slight adverse to moderate adverse effect during construction and at Design Year 2022 and the National cycle Route 4/61 to the south east off the junction would experience moderate adverse effects during construction and at Design Year 2022. All the receptors by Design Year 2037 would experience a neutral visual effect due to the establishment of the planting (see Annex A1, Environmental Masterplan, Sheet 22 (Application Document Reference 7-4).

3.4.8 The visual effects of the Datchet Road overbridge realignment for users of Upton Court are illustrated on Drawing 8.2 Sheet 12 and described in Appendix 8.3. It is reported that users of Upton Park would experience moderate adverse effects during construction and a slight adverse visual effect at Design Year 2022. By Design Year 2037 users would experience a neutral visual effect due to the establishment of the planting (see Annex A1, Environmental Masterplan, Sheet 23 (Application Document Reference 7-4).

3.4.9 The visual effects of the M4 Junction 5 Langley Interchange are illustrated on Drawing 8.2 Sheet 13 and described in Appendix 8.3 and in paragraph 8.10.15 item a) of the ES. The extent of the vegetation removal at the M4 Junction 5 is shown in EDR, Annex 2 Vegetation Clearance Sheet 25 (Application Document Reference 7-4) and described in paragraphs 8.11.13 and 8.11.15 of the ES. It is reported that the nearby residential properties on Grampian Way and London Road to the north, residential properties on Sovereign Heights to the south and Welland Close to the south east would experience slight adverse effects during construction and at Design Year 2022. These properties,

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other than those at Sovereign Heights, by Design Year 2037 would experience a neutral visual effect due to the establishment of the planting (see EDR, Annex A1, Environmental Masterplan, Sheet 25 (Application Document Reference 7-4). The properties at Sovereign Heights would continue to experience a residual slight adverse visual effect at Design Year 2037.

3.5 SBC is also concerned about the visual impact of the proposed gantries, in particular the following which have the potential to be obtrusive from neighbouring residential areas:

(a) G5-11 Huntercombe Spur (not specifically identified on Sheet 20 Inset 1);

(b) G5-10 Cippenham, Mercian Way Recreation Ground;

(c) G5-03 and G5-5, Wood Lane;

(d) G4-16 east of A332 Prince of Wales Bridge, adjacent to Winvale (SBC supports the ExA’s query about the scope for mitigation);

(e) G4-13 Datchet Road; and

(f) G4-02 Ditton Road.

Highways England's Comment

3.5.2 The purpose of the landscape and visual assessment contained in Chapter 8 of the ES is to identify and report the main effects of the Scheme. The preparation of the ES was initially based on the information contained in the PEIR which sets out locations where potential visual effects may arise. Chapter 8 of the ES takes account of the Scheme development since the submission of the PEIR. The ES focusses on reporting areas where visual effects are expected, which means that some not significant effects have not been explicitly reported, although all potential effects have been assessed. The potential visual effects of the gantries raised in the representation of SBC are each considered in turn below

3.5.3 The visual effects of gantry G5-11 (Type 3, 12.8m high) are illustrated on Drawing 8.2 Sheet 10 and described in Appendix 8.3. The adjacent residential properties on South Close to the east would experience slight adverse effects during construction, at Design Year 2022 and Design Year 2037.

3.5.4 The visual effects of gantry G5-10 (Type 3, 13.3m high) have not been specifically reported in Chapter 8 of the ES as it is considered that there would not be a significant effect at this location This gantry is relatively remote from visual receptors as it is located on the west bound side of the Scheme to the south west of the Mercian Way

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Recreation Ground. It is anticipated that the installation and operation of this gantry will be shielded in most views form the Recreation Ground by intervening vegetation and where it is visible will be glimpses in gaps during the summer and in heavily filtered views in winter. On that basis, the visual effects are neutral.

3.5.5 The visual effects of Gantries G5-05 (Type 5, 9.2m high) and G5-03 (Type 3, 12.8m high) would not be subject to a significant effect at either location. (See receptors 11.1.1, 11.1.2, 11.3.2 and 11.3.3 for the nearest assessed visual proxies). These gantries are located on either side of the Scheme, immediately to the west and east of the proposed Wood Lane overbridge realignment respectively. The nearest receptors are the properties on Wood Lane which would experience moderate adverse visual effects during construction due to the adjacent bridge realignment works and a slight adverse effect at design Year 2022.

3.5.6 The focus of the view from these properties is to the south east away from the two proposed gantries, and gantry G5-03 being sited beyond the retained south west facing approach embankment to the Wood Lane overbridge and its associated retained vegetation. The gantries will be visible in views from users of the Wood Lane overbridge, as they cross the M4 (see receptor 11.3.3). However, considering the visual context of a low value urban environment heavily influenced by the motorway and its traffic, it is considered they would have a minor change on the view which, at worst, would result in a slight adverse significance of visual effect.

3.5.7 The visual effects of Gantries G4-16 (Type 1, 13m high on eastbound side) are illustrated on Drawing 8.2 Sheet 11 and described in Appendix 8.3 in paragraph 8.10.15, item d of the ES. The adjacent residential properties at Winvale to the north would experience moderate adverse visual effects during construction at Design Year and Design Year 2037. Due to the limited land available at this location, which is on an existing elevated section of the M4 motorway, it is not possible to mitigate the effects of gantry G4-16 on the adjacent residential properties.

3.5.8 The visual effects of gantry G4-13 (Type 5, 9.2m high) would not be significant (See receptors 12.1.1, 12.3. 1, 12,3,2 and 12.2.2, illustrated on Drawing 8.2 Sheet 11 and described in Appendix 8.3)for the nearest assessed visual proxies). This gantry is located on the eastbound side of the Scheme, immediately to the west of the proposed Datchet Lane overbridge realignment. There is an existing gantry at this location and in combination with the retained existing vegetation, and the relative position of the proposed gantry to the residential properties at the Myrke, the visual effects of this gantry would be limited, and is neutral.

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3.5.9 The visual effects of gantry G4-02 (Type 3, 15.5m high) would not be significant (See receptors 12.2. 4, and 12.3.7, illustrated on Drawing 8.2 Sheet 11 and described in Appendix 8.3 for the nearest assessed visual proxies). This gantry spans both carriageways of the Scheme and is relatively remote from residential properties, with the closest located on Ditton Park Road to the north. It is anticipated that the gantry would be shielded by intervening vegetation in views from the residential receptors. The gantry would be seen in transient views form the receptors of Riding Hood Lane (Receptor 12.2.4) to the north and the cycle route on the B470 (Receptor 12.3.7) to the south. It is slight adverse reducing to neutral by Design year 2037.

3.6 SBC agrees with the ExA that more information is needed on the design of new lighting- especially those to be mounted on the central barrier - and how light spill would compare with the existing.

Highways England's Comment

3.6.1 Highways England disagrees that further lighting design information is needed. The proposals are described in paragraph 4.2.4(c) of the ES (Application Document Reference 6-1) and in paragraph 6.3.44 of the Engineering and Design Report (Application Document Reference 7-3). The existing motorway lighting is provided via 250W and 400W high-pressure sodium luminaires. The Scheme will use modern Light Emitting Diode (“LED”) luminaires throughout.

3.6.2 LED luminaires control the lighting distribution to project light onto the road surface. The luminaires will be installed horizontally and there will be no upward light distribution. The total light output from the LED luminaires to achieve the required road illumination levels will be up to 50% less than that of the existing high pressure sodium luminaires. On that basis, there will be both less lighting spill and less light pollution.

3.7 The installation of new or replacement environmental (noise) barriers could have a significant visual impact depending on the design and materials; provision of screening by vegetation; and the increased heights suggested in the Enhanced Mitigation Strategy (APP-351). The proposed barriers on the Windsor Rail Branch bridge and Junction 5 Langley Interchange bridge would be particularly prominent features and need close attention.

Highways England's Comment

3.7.1 Highways England disagrees that the new or replacement noise barriers, including the increased heights suggested in the Enhanced Mitigation Strategy will have a significant visual impact. The visual assessment assumed that the new or replacement noise barriers would be of timber construction and be of

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similar appearance and weathering properties to the existing noise barriers. This is the usual choice for noise barriers on highway schemes. In many locations, and where appropriate, these barriers are used in conjunction with planting proposals, as indicated in the Engineering and Design Report, Annex A1, Environmental Masterplan (Application Document Reference 7-4).

3.7.2 Sections 8.6 to 8.13 of Chapter 8 of the ES (Application Document Reference 6-1) considered the existing noise barriers and the new and replacement noise barriers, both as a feature in the landscape, and as screening element to traffic, from adjacent visual receptors on a link by link basis. The assessment was carried out in relation to each noise barrier.

3.7.3 It is likely that where noise barriers would be located on a structure such as a bridge, they would be made of an alternative more durable material. At these locations the noise barrier would be appropriately designed to take account of the urban or landscape context. The detail design of alternative barrier materials, if required, would be developed in consultation with the local planning authority. It is not anticipated that the choice of an alternative material for the noise barriers to that assessed in Chapter 8 of the ES (Application Document Reference 6-1) would affect its findings. In relation to the proposed barriers on the Windsor Rail Branch Bridge and at the M4 Junction 5 Langley Interchange, these new noise barriers would be visible elements associated with the adjacent structures, but would not be considered prominent features in the context of the Scheme. The noise barriers would also help to screen much of the traffic on these structures. Over time, the appearance of the barriers at these locations, along with the structures they are part of, would diminish as the surrounding landscape proposals establish resulting in limited visual effects by Design Year 15.

3.8 It is noted that draft DCO Requirement 9 refers to a landscaping scheme being submitted to the Local Planning Authority for approval. Draft DCO Requirements 7 and 8 also mean that both the CEMP and EMP would need SBC approval. However SBC is concerned that the outline CEMP (APP-293) is not sufficient to secure mitigation and that too many details are left to the future contractor. This concern is increase in the light of the ExA pointing out that M4 Smart Motorway DCO: Slough Local Impact Report Requirement 8 as drafted leaves it open for the CEMP being modified by the HE after the Scheme had commenced without further reference to SBC and without any guarantee that the necessary mitigation would in fact be implemented.

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Highways England's Comment

3.8.1 Highways England does not consider SBC's concerns to be warranted. As SBC acknowledges, the CEMP and EMP require SBC approval under Requirements 7 and 8 of the draft DCO.

3.8.2 In relation to Requirement 8, Highways England repeats its response to the Examining Authority's First Written Questions:

3.8.3 Whilst noting that the wording in this requirement that allows for modification of the CEMP was included in the drafting of the A556 (Knutsford to Bowden Improvement) Development Consent Order 2014 at requirement 4(7), Highways England agrees to the deletion of sub-paragraph 3 in requirement 8. This amendment is reflected in the revised draft of the DCO submitted at Deadline III.

Construction Compounds

3.9 Proposed Compound No. 9 would be located in a prominent position at the junction of Sutton Lane and A4 London Road/ Colnbrook Bypass. SBC is concerned about its potential visual impact, especially in relation to nearby housing and when fringe trees and hedges are not in leaf. As suggested by the ExA, the impact of construction compound lighting and from any night time construction works should have been assessed: such lighting could detract significantly from residential amenity.

Highways England's Comment

3.9.1 The landscape and visual effects of Construction Compound 9 and its associated activities are described in paragraph 8.11.14 of the ES (Application Document Reference 6-1). This construction compound would result in a neutral effect on the local landscape within the undefined urban fringe landscape.

3.9.2 The visual effects of Construction Compound 9 and its associated activities on the adjacent residential properties on Trent Way to the west visual receptors are described in paragraph 8.11.18 item a) of the ES. This assessment is the worst case scenario and is based on the filtered view from the upper storey windows which takes into account the winter situation when the hedgerow and trees are not in leaf. From the ground storey views, the relatively dense nature of the hedgerow and the proposed stripped topsoil storage mound provided beyond would screen much of the compound during both summer and winter. Therefore, it is anticipated that construction compound 9 and its associated

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activities would result in a moderate adverse visual effect on the upper storey views from the adjacent residential properties along Trent Way.

3.9.3 The impact of construction compound lighting and from any night time construction works was assessed by Highways England. Paragraph 8.10.3 of the ES (Application Reference Document 6.1) and Drawing 8.1, Sheet 13 of the ES (Application Document Reference 6-2) show that Construction Compound 9 would be located within the ILP environmental zone 2 low district brightness area. This location is influenced by night time lighting from the adjacent urban area, the A4 and local road. The proposed low level lighting within this construction compound would constitute minimal change to baseline conditions given this context.

3.9.4 With reference to Drawing 8.2 Sheet 13 (Application Document Reference 6- 2), Appendix 4.3 of the ES (Application Document Reference 6-3) and Appendix 8.3 of the ES (Application Document Reference 6-3), there are three visual receptors (ref. 13.1.14, 13.1.15 and 13.2.2) with views to the construction compound site. The existing background urban night time lighting in combination with either sections of perimeter solid hoarding used in combination with existing retained hedgerow vegetation around the perimeter of Construction Compound 9 would minimise the light spill of the compound lighting on to adjacent residential properties. The effects of the lighting during construction will be controlled by the Construction Environmental Management Plan (“CEMP”) (an Outline CEMP is provided in Appendix 4.2A of the ES (Application Document Reference 6-3)), and secured by Requirement 8, Schedule of the Draft DCO (Application Document Reference 3-1). The CEMP includes measures such as the use of carefully positioned directional lighting, as set out in paragraphs 5.6.7 and 5.6.8 of the Outline CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3), so that any visual effects arising from the night time lighting of construction activities would be of a limited nature and would not constitute significant effects.

3.9.5 On the above basis, Highways England disagrees that lighting in this location could significantly detract from residential amenity.

3.10 Proposed Compound No. 8 is located outside the Borough boundary but has the potential to be visually obtrusive, particularly –as with Compound No. 9 - when existing vegetation is not in leaf.

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Highways England's Comment

3.10.1 Highways England disagrees that Construction Compound 8 has the potential to be visually obtrusive. The landscape and visual effects of Construction Compound 8 in association with other construction activities adjacent to it are described in paragraph 8.10.14 of the ES (Application Document Reference 6- 1). In relation to the potential visual receptors within Slough, Construction Compound 8 would be contained by the retained south west facing approach embankment to the Datchet Road overbridge and its associated vegetation, which would screen it from the residential properties at the Myrke and by the existing M4 and associated vegetation to the north, which would screen it from Upton Court Park to the north.

Flooding

3.11 SBC published its Strategic Flood Risk Assessment in May 2012 and notes the comments of the Environment Agency in RR-249 about HE’s floodplain risk assessment. The Scheme proposes the extension of the Chalvey Culvert which passes under the M4: SBC has no adverse comments on the proposed works subject to them being carried out with minimum disturbance to existing vegetation.

Highways England's Comment

3.11.1 Highways England confirms that it will adopt a precautionary approach to the protection of vegetation, watercourses and habitats during construction, to minimise potential impacts and disturbance. This approach is described in paragraphs 9.3.1 to 9.3.9 of the Outline CEMP (Appendix 4.2A to the ES (Application Document Reference 6-3)) and is secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

Ecology and nature conservation

3.12 SBC does not challenge the conclusions of Table 9.5 APP-149 about the residual effect of the Scheme on ecology and nature conservation. The presence of the Herschel Park Local Nature Reserve is recorded in APP-149 but SBC is unable to find a full description of this LNR in the document. It is not clear what the potential impact of the Scheme would be on the south-eastern corner of the reserve in relation to works on the Datchet Road overbridge and gantries G5-03 and G5-05.

Highways England's Comment

3.12.1 Highways England accepts that the impact upon Herschel Park Local Nature Reserve (“LNR”) was not clearly addressed within the ES. Additional details, including an impact assessment statement, are provided below.

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3.12.2 Herschel Park LNR is situated adjacent to the north side of the Scheme and to the west of Datchet Road Overbridge between chainages 24400 and 24300. The Land Plans, Sheet 23 (Application Document Reference 2-2) and Book of Reference (Application Document Reference 4-3) show temporary land-take of Special Category Land for parcel 23-04, which lies within the LNR. This land will be used for a Thames Water water main diversion which will require vegetation clearance and deep excavations. This land is needed only during the construction phase.

3.12.3 With regard to the gantries identified by SBC, G5-03 and G5-05 are not located near Herschel Park. However, Gantry G4-13 will be located within the motorway boundary close to the Datchet Road bridge site. No impacts on Herschel Park are anticipated during construction of gantry G4-13.

3.12.4 General ecological mitigation measures (e.g. in relation to the temporary removal of vegetation and in relation to nesting birds and reptiles) are outlined in Section 9.3 of the Outline Construction Environmental Management Plan (Appendix 4.2A of the ES) (Application Document Reference 6-3). Land cleared of vegetation for temporary construction works will be replanted following construction, using native species appropriate to the local area (see paragraph 9.4.24 of the ES, Application Document Reference 6-1). Sheet 23 of the Environmental Masterplan (Annex A of the Engineering and Design Report) (Application Document Reference 7-4) shows proposed planting within this area.

3.12.5 Receptor value: The LNR concerned largely comprises scrub with semi-mature trees. These habitats are likely to be used by nesting birds, and small numbers of slow-worm were found in suitable adjacent habitats. Badger surveys have been undertaken, but no badger setts have been identified within the Order limits. The invasive plant species Japanese knotweed has been recorded close to Datchet Road Overbridge, close to the eastern edge of the LNR. Herschel Park LNR and its habitats and species have been valued at the ‘local’ (defined as: ‘Areas of habitat; or populations/communities of species considered to appreciably enrich the habitat resource within the local context (such as veteran trees), including features of value for migration, dispersal or genetic exchange’; Interim Advice Note 130/10) or ‘low’ level.

3.12.6 Impact magnitude: The loss of a relatively small proportion of the LNR is considered to be a ‘minor’ impact (defined as: ‘Some measurable change in attributes, quality or vulnerability; minor loss of, or alteration to, one (maybe

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more) key characteristics, features or elements (Adverse)’ in DMRB Volume 11 Section 2 Part 5 HA 205/08).

3.12.7 Significance of Effect: Through the use of the matrix at Table 9.4.2 in Appendix 9.4 of the ES (Application Document Reference 6-3), the impact upon the LNR and its component species and habitats is considered to be ‘neutral’ (defined as: ‘No effects or those that are beneath levels of perception, within normal bounds of variation or within the margin of forecasting error’ in DMRB Volume 11 Section 2 Part 5 HA 205/08).

3.13 SBC notes that the presence of bats was detected at the Windsor Rail Branch bridge (9.10.37 of APP- 149), a factor that would need to be taken into account during the construction phase. It is also noted that a full habitat survey was not made at the site of the proposed Compound No. (9.11.14 of APP- 149).

Highways England's Comment

3.13.1 Comprehensive bat surveys have been undertaken along the Scheme. No bat roosts were confirmed between Junctions 8/9 and 3 and no works to structures containing roosts are anticipated, as explained in paragraphs 9.4.66 and 9.4.67 of the ES (Application Document Reference 6-1). Notwithstanding, bats are present along the Scheme, including the area around Windsor Branch Railway underbridge, as described in paragraph 9.10.31 of the ES (Application Document Reference 6-1). Highways England confirms that the presence of bats will be taken into consideration during the works. Proposals for mitigating bats, including the need to obtain a European Protected Species licence to disturb or remove a bat roost, are described in paragraphs 9.4.67 to 9.4.74 of the ES (Application Document Reference 6-1).

3.13.2 All compound areas have now been surveyed with the exception of Construction Compound 9 where access notices are being served. Any additional surveys and pre-construction surveys (including subsequent mitigations including any licence requirements and/or legal compliance) have been reported within Appendix 5.3 of the ES (Application Document Reference 6-3) and/or will be actioned via the Construction Environmental Management Plan, and therefore secured under Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

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Air Quality

Operational Scheme

3.14 Air quality is a material planning consideration and a significant public health issue affecting the health of hundreds of thousands of the general population in England and potentially thousands of residents in Slough who live within Air Quality Management Areas. The principal cause of poor air quality in Slough is from road traffic emissions. The principal cause of poor air quality within Air Quality Management Area (AQMA) 1, located in Slough along sections it shares with the M4, is road traffic emissions from the M4. All of SBC’s AQMAs have been declared due to breaches of the National

Air Quality Objective for annual nitrogen dioxide (NO2).

Highways England's Comment

3.14.1 Highways England accepts that air quality is a material planning consideration, and is one of the environmental topics specifically addressed in the National Policy Statement for National Networks. Highways England's assessments took account of Air Quality

Management Areas (“AQMAs”) for exceedances of the annual mean NO2 objective and

Highways England agrees that the primary source of NO2 in those AQMAs is from road

traffic. Potential increases in annual mean NO2, both within and outside those AQMAs, has been considered in the air quality assessment and detailed modelling of those potential effects has been undertaken where a potentially significant increase in traffic flows has been predicted.

3.15 SBC has a comprehensive air quality monitoring network in place including monitoring air quality within AQMA 1, M4 Air Quality Management Area and the results are presented in Table 1 below and clearly illustrate that sites are consistently breaching the National Air Quality Objectives/EU limits (figures in red).

Table 1: Slough Borough Council Air Quality Monitoring Network M4 (AQMA 1)

Site Type Distance Grid Reference Air Quality Data Sets for M4 AQMA 1 5 year within From M4 (2009 - 2013) Ratified Annual Mean Ann. AQMA (ug/m3) Av. M4 X Y 2009 2010 2011 2012 2013

Chalvey Air Yes 45m 496562 179019 44.4 41.8 44.2 39.0 37.7 41.2 Quality (north) Monitoring Station

Paxton Yes 30m 496050 179258 40.0 38.0 38.9 47.5 42.1 41.3 Avenue (north)

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Spackmans Yes 40m 496272 179187 39.6 41.0 44.0 43.4 43.6 42.3 Way (north)

Ditton Road Yes 60m 500851 177890 38.6 40.9 40.5 41.0 37.2 39.6 (north)

Chalvey Yes 45m 496562 179019 41.4 40.3 41.1 40.8 38.0 40.3 Station (north)

Winvale Yes 15m 497488 179090 42.1 40.9 46.9 48.3 44.5 44.5 (north)

Grampian Yes 50m 501382 178101 42.1 42.3 48.1 45.1 43.3 44.2 Way (north)

Torridge Yes 30m 501637 177999 36.6 47.4 41.2 39.5 43.3 41.6 Road (south)

Highways England's Comment

3.15.1 Current measurement data within Slough demonstrates that some areas, including those close to the M4, are currently exceeding the air quality objective value (40 µg/m3), consistent with the declarations of AQMAs. Local measurement data collected across the Scheme study area, including those within Slough Borough Council’s administrative area, were used within the air quality assessment for the verification of the detailed modelling of air quality effects.

3.15.2 Details of the measurement data used within the air quality assessment are set out in Appendix 6.4 of the ES (Application Document Reference 6-3). Measurement locations are also shown on Drawings 6.1 to 6.32 and associated insets (Application Document Reference 6-2).

3.16 SBC raises concerns about residential receptors that may be affected by both the operational and construction phases of the Scheme and in particular where the Environmental Statement (ES) lacks sufficient detailed assessment to draw conclusions or where there is absence of proposed mitigation due to exposure of poor air quality.

Highways England's Comment

3.16.1 For the operational phase of the Scheme, paragraphs 6.9.15, 6.9.16, 6.10.17, 6.10.18, 6.10.19, 6.11.14 and 6.11.15 of the ES (Application Document Reference 6-1) identify the predicted air quality effects of the Scheme on the 382 sensitive receptors located with the Slough Borough Council administrative area that were explicitly modelled in the air quality assessment. These receptors are also shown on Drawings 6.11, 6.12 and 6.13 and associated insets (Application Document Reference 6-2). The full Scheme results for all receptors considered in the assessment are presented in Appendix 6.6 of the ES

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(Application Document Reference 6-3). This is considered to be a sufficient number of receptors upon which to evaluate air quality effects associated with the Scheme. The numbers of receptors considered, combined with the detailed air quality modelling utilised, as described in paragraphs 6.2.52-6.2.64 and Appendix 6.4 of the ES (Application Document Reference 6-3), has provided a very detailed assessment of potential air quality effects.

3.16.2 The predicted changes at these receptors are imperceptible (0.4 µg/m3 or less) to small 3 (>0.4-2.0 µg/m ) increases in annual mean nitrogen dioxide (“NO2”). In total, 11 small

increases in annual mean NO2 are predicted within Slough with the Scheme at receptors also predicted to experience annual mean concentrations above the air quality objective (40 µg/m3).

3.16.3 The air quality assessment does not predict a significant effect on sensitive receptors as a result of the Scheme, and therefore no air quality specific mitigation measures are proposed.

3.16.4 A wide range of air quality mitigation measures for the construction phase, including both demolition and construction, have been identified and are provided for in the Outline Construction and Environmental Management Plan ("CEMP") (Appendix 4.2A of the ES) (Application Document Reference 6-3). This includes measures to control dirt/dust and noise that will result from the construction and operation of the Scheme (paragraphs 6.2.1 and 12.3.1 of the Outline CEMP). A summary of all of the mitigation proposed for the Scheme is set out in a Table of Mitigation, which is provided at Appendix 1 to the Explanatory Memorandum (Application Document Reference 3-2). The CEMP is secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

3.16.5 In particular, where residential properties are close to construction compounds (such as Construction Compound 9, near Brands Hill), additional mitigation measures have been proposed. The measures are based on Institute of Air Quality Management ("IAQM") guidance and are presented in Appendix 6.1 of the ES (Application Document Reference 6-3) and at paragraphs 6.2.1 and 6.3.4 of the Outline CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3). These measures are secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1) and will be adopted and refined in consultation with local boroughs, parish councils and local residents.

3.17 In response to the ExA’s question: ‘whether there are locations where EU limits for traffic pollutants would be exceeded as a result of the scheme?’ SBC considers that there: these are discussed below and set out in Table 2.

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Highways England's Comment

3.17.1 Highways England has provided a full response to the Examining Authority's Question concerning compliance with EU Limit Values (E4.6.1) in Highways England's Response to First Written Questions, submitted on 8 October 2015.

3.17.2 Regarding the results presented in Table 2, the predicted annual mean concentrations of

NO2 at the receptors identified are above the annual mean air quality objective in the opening year of the Scheme (2022).

3.17.3 The air quality modelling undertaken for sensitive receptors (i.e. residential properties) for the Scheme has been considered against air quality objective values and EU Limit Values have been considered through the approach outlined in the response to paragraph 3.18 below, which concludes that the Scheme has a low risk of adversely affecting compliance with EU Limit Values and the Ambient Air Quality Directive.

3.18 The ExA asks ‘Having regard to the final judgement of the Supreme Court in the “ClientEarth” case, does the assessment of air quality impacts set out in the ES indicate that the scheme would comply with this requirement of the NNNPS?’ There are Slough residents predicted to be affected by breaches of

the EU Limit on NO2 annual mean at the year of opening (2022) and therefore, without mitigation, the Scheme would not in our view comply with the requirements of the NNNPS. This would be for either of the following scenarios: for a compliant zone (SE zone) becoming non-compliant at year of operation (2022); or if the SE zone does reach compliance by 2020 as outlined by the Government’s proposed draft action plans then the M4 Smart Motorway may delay compliance with the EU limits within the shortest possible time, unless mitigation is adopted

Highways England's Comment

3.18.1 Highways England has provided a full response to the Examining Authority's Question E4.6.1 in Highways England's Response to First Written Questions, submitted on 8 October 2015.

3.18.2 As described in relation to the response above to paragraph 3.17, there are residential properties within Slough predicted to exceed the objective value with the Scheme in place. However, this does not constitute an exceedance of EU Limit Values, which are reported based upon information gathered by Defra only.

3.18.3 Highways England therefore does not agree that the Scheme does not comply with the requirements of the NN NPS. A risk assessment has been undertaken to establish the potential for the Scheme to affect the information reported by Defra to the EU, and in particular to test whether the Scheme would cause:

Deadline III - Response to Local Impact Reports 29 Highways England

 a compliant zone becoming non-compliant; and/or

 delay Defra’s date for achieving compliance for the zone i.e. the change on a road link would result in concentration higher than the existing maximum value in the zone; and/or

 result in an increase in the length of roads in exceedance in the zone which would be greater than 1% when compared to the previous road length.

3.18.4 The risk assessment has been undertaken using Highways England Interim Advice Note (“IAN”) 175/13 ‘Updated air quality advice on risk assessment related to compliance with the EU Directive on ambient air quality and on the production of Scheme Air Quality Action Plans for user of DMRB Volume 11, Section 3, Part 1 ‘Air Quality’.

3.18.5 Following this methodology, the Scheme is not anticipated to cause any of the three above situations to occur. This is because the compliance assessment identified that there was only one area where Pollution Climate Mapping Model (“PCM”) road sections within the study area of the local operational air quality assessment were expected by Defra to be non-compliant in the Opening Year (2022) of the Scheme.

3.18.6 The PCM road links comprise a section of the A4 located between Warkworth Gardens and Windmill Road in Brentford.

3.18.7 However, the resultant concentration predicted at this location with the contribution of

the Scheme was not higher than the highest PCM Road section annual average NO2 concentration of 69.5 µg/m3 within the Greater London Urban Area, and additionally the change in concentration along the A4 PCM road section is imperceptible (i.e. less than 0.4 µg/m3).

3.18.8 No other PCM road sections were identified to be in non-compliance in the Opening Year (2022) in the Reading/Wokingham Urban Area and South East zone which cover the Scheme and local operational air quality assessment study area. The Slough Borough Council administrative area is within the South East zone.

3.18.9 On the basis of this evaluation, the Scheme is considered to have a low risk of causing a compliance issue against EU Limit Values and no air quality action plan for the Scheme is required. The compliance risk assessment is reported in paragraphs 6.15.4 to 6.15.7 of the ES (Application Document Reference 6-1) and this confirms that the Scheme would not lead to any of the three tests outlined in paragraph 3.18.3 being met.

3.18.10 It is acknowledged that a draft plan to improve air quality in the UK was issued by Defra for consultation on 12 September 2015 (https://consult.defra.gov.uk/airquality/draft-aq- plans). This plan outlines the approach proposed to bring zones not in compliance back

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in to compliance as soon as possible. The consultation on the draft plan is scheduled to end on 6 November 2015 and the plan is scheduled to be submitted to the EC by the end of 2015.

3.18.11 Low emission zones (Clean Air Zones) are not specified for either the Reading/Wokingham Urban Area Zone or the South East Zone. Highways England understands that a potential CAZ for Greater London Agglomeration referred to in Defra’s consultation on air quality plans is being considered, although the exact details are unknown at this time. Consequently, it is not possible at this time to comment how, if at all, the scheme would interact with any possible future CAZ reference in Defra’s consultation documents

3.18.12 The draft Defra air quality plan suggests that the Reading/Wokingham Urban Area and South East zones within the local air quality assessment study area for the Scheme will continue to be compliant with EU Limit Values for annual

average NO2 by the time the Scheme opens in 2022.

3.18.13 Therefore, the publication of the draft Defra air quality plans does not change the findings of the compliance risk assessment undertaken for the Scheme as set out in paragraphs 6.15.4 to 6.15.7 of the ES (Application Document Reference 6-1). It is also considered very unlikely that any changes in the final air quality plans would alter this position.

3.18.14 On this basis, mitigation is not required for the Scheme to be in compliance with the NN NPS, nor is it required to be adopted in the potential scenarios outlined by SBC.

3.19 The ExA asks ‘to what extent have the local authority Environmental Health Officers and Air Quality Officers been consulted on the assessment set out in Chapter 6? (APP-146) Can the applicant, local authorities and other interested parties identify areas of agreement and disagreement with regard to the assessment of air quality impact set out in the ES?’ There was no pre-consultation on the methodology applied for air quality assessment prior to submission of the ES. SBC accepts the methodology applied by HE’s consultant, including its limitations which are significant in respect of adjustment factors applied, but does not wish to dwell on technical aspects of the methodology. SBC does not accept the assessment of significance applied by the HE consultant and their justification for

not adopting mitigation for residential receptors exposed to breaches of the EU limit for NO2 annual mean.

Deadline III - Response to Local Impact Reports 31 Highways England

Highways England's Comment

3.19.1 Highways England has provided a full response to the Examining Authority's Question E4.6.2 in Highways England's Response to First Written Questions, submitted on 8 October 2015.

3.19.2 Highways England notes that the assessment of significance applied to the Scheme has been accepted by the Secretary of State in relation to highways development, including highways development by way of development consent order under the Planning Act 2008. The assessment of significant effects on air quality is determined following the methodology set out in Interim Advice Note 174/13 ‘Updated advice for evaluating significant local air quality effects for users of DMRB Volume 11, Section 3, Part 1 ‘Air Quality’ (HA207/07)’, which has been accepted by the Secretary of State to be a suitable methodology for determining significance for air quality for a highways scheme.

3.19.3 The methodology for the evaluation of significance in relation to the air quality assessment was set out in the Scoping Report for the ES (issued August 2014). Slough Borough Council did not provide comments on the Scoping Report that indicated that they were not satisfied this.

3.19.4 In this approach the evaluation considers total concentrations of pollutants, changes in pollutant concentrations and numbers of sensitive receptors affected. In order for mitigation to be recommended a combination of air quality above air quality objectives with increases in pollutant concentrations of more than 0.4 µg/m3 at a number of sensitive receptors is required. In this instance, whilst some areas were identified within Slough Borough Council’s administrative area to have concentrations of nitrogen dioxide above air quality objectives, only 11 out of 382 modelled receptors were predicted to have a small increase in nitrogen dioxide concentrations above the objective value.

3.19.5 As set out in the overall operational assessment of significance of the Scheme in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1), the air quality assessment does not predict a significant effect on sensitive receptors overall as a result of the Scheme, and therefore no air quality specific mitigation measures are proposed.

3.19.6 Additionally, for the reasons stated in the response to paragraph 3.18 above with respect to the Ambient Air Quality Directive, mitigation is not required for the Scheme to be in compliance with the NN NPS. SBC do not identify the basis upon which they disagree with the assessment of significance of the Scheme's consultant, nor the basis of their disagreement with justification for the fact that no mitigation is offered.

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3.20 Outdoor air quality is one of the most significant public health issues affecting the modern world, and

there is a growing body of medical evidence that the prolonged exposure to NO2 pollution may have longer term impacts on health, in particular lung function and respiratory symptoms, and there is more data coming through epidemiological studies. The most recent study completed by Kings College for

London exposure assumes increased in mortality rates as a result of exposure to NO2 this follows guidance from the World Health organisation,. see link to Kings College report.

https://www.london.gov.uk/sites/default/files/HIAinLondonKingsReport14072015final.pdf

3.21 Government policy with respect to air quality has substantially changed in recent months, further due to the successful Supreme Court Challenge by ‘Client Earth’. The UK Government have now submitted (September 2015) a consultation on draft plans to improve air quality. We would request the ExA to take these new draft action plans and evidence base into account, as these plans are likely to have repercussions for the M4 Smart Motorway Scheme.

Highways England's Comment

3.21.1 The assessment of air quality focuses on locations which are predicted to have air quality in the opening year of a Scheme above air quality objectives. This is because the air quality objective values have been set at concentrations that provide protection to all members of society, including more vulnerable groups such as the very young, elderly or unwell.

3.21.2 The ClientEarth judgement (April, 2015) requires the UK Government to prepare a revised national air quality action plan to bring zones which are currently in non- compliance with EU Limit Values back in to compliance as soon as possible. The Supreme Court judgement requires that this plan should be submitted to the EC by the end of 2015.

3.21.3 A draft plan to improve air quality in the UK was issued by Defra for consultation on 12 September 2015 (https://consult.defra.gov.uk/airquality/draft-aq-plans). This plan outlines the approach proposed to bring zones not in compliance back in to compliance as soon as possible. The consultation on the draft plan is scheduled to end on 6 November 2015 and the plan is scheduled to be submitted to the EC by the end of 2015. The consultation on the draft plans to improve air quality indicates that Defra considers that the submission of the air quality plan will fulfil the requirements of the Supreme Court judgement.

3.21.4 The draft Defra air quality plan suggests that the Reading/Wokingham Urban Area and South East zones within the local air quality assessment study area for the Scheme will

continue to be compliant with EU Limit Values for annual average NO2 by the time the

Deadline III - Response to Local Impact Reports 33 Highways England

Scheme opens in 2022. The draft Defra air quality plan also indicates that the Greater London Urban Area, which is also within the local air quality assessment study area for the Scheme, will remain non-compliant following the opening of the Scheme in 2022, with the date of compliance anticipated to be 2025 instead of 2030. Additionally, the

areas of highest annual average NO2 concentrations are still anticipated to be located outside of the study area for the Scheme (e.g. at Marylebone Road). Hence they are not affected by the Scheme. The dates by which the Greater London zone will become compliant relate to the time taken for air quality to improve in these locations to

concentrations below the EU Limit Value for annual average NO2 concentrations, rather than the locations within the Scheme local operational air quality assessment study area.

3.21.5 Therefore, the publication of the draft Defra air quality plan to address the requirements of the recent Supreme Court judgement does not change the findings of the compliance risk assessment undertaken for the Scheme as set out in paragraphs 6.15.4 to 6.15.7 of the ES (Application Document Reference 6-1). It is also considered very unlikely that any changes in the final air quality plans would alter this position and as such, these draft plans are not anticipated to have repercussions for the M4 Smart Motorway Scheme.

3.22 Perhaps of most significance is the evidence annex and reference to NO2 exposure where it applies by

the recent Committee on Medical Effects of Air Pollutants (COMEAP) advice directly linking NO2 exposure to mortality. DEFRA has applied this evidence to the exposure levels across the UK and

suggests that exposure to NO2 is increasing mortality by the equivalent of 23,500 deaths per year and with a range of 9,500 to 38,000 deaths. Whilst the evidence on health impacts is still being assessed and is subject to a number of uncertainties a precautionary approach has been applied. Even applying

the COMEAP lowest coefficient of 1% the monetised health impact of reducing NO2 to the UK is £980

million. Applying the central coefficient (2.5%) the monetised health impact of reducing NO2 to the UK is £2,495 million. See link https://consult.defra.gov.uk/airquality/draft-aq-plans

Highways England's Comment

3.22.1 Highways England is aware of the COMEAP advice, and notes the Borough Council’s calculations. However, this global figure is clearly not relevant to the M4.

3.22.2 A Health Impact Assessment has been prepared for the Scheme. In addition, communications between Highways England and Public Health England (dated 8 October 2015) has resulted in Public Health England stating that they agree “that the methodologies used for the assessment of health impacts via air, land and water are appropriate”. Then regarding air quality, Public Health England go on to say:

“As described in paragraph 6.2.25 of the Environmental Statement (Application Document Reference 6.1), the air quality objectives, which form the basis of the

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assessment of the impact of the Scheme on air quality, are selected based on the way they affect human health, with mean annual objectives relating to chronic impacts on human health and 24 hour objectives relating to acute impacts on human health. Paragraph 6.2.81 of the ES (Application Document Reference 6.1) explains that sensitive receptors have been selected based on locations where people will be present, given the potential impact of air quality on human health. It is agreed that the approach set out in the ES (Application Document Reference 6.1) is suitable to assess the impacts of the Scheme on air quality as it affects human health.”

However, it is agreed that impacts on health are addressed in the various topic-specific chapters of the ES (Application Document Reference 6.1) in accordance with the National Networks National Policy Statement as follows:

Air quality.

An overview of the Scheme-wide impacts on air quality is presented in paragraphs 6.4.1 to 6.4.5 of the ES (Application Document Reference 6.1), followed by the results of the assessment of the Scheme on the local air quality on a link-by-link basis in Sections 6.5 to 6.13 of the ES (Application Document Reference 6.1), and for receptors along off-Scheme roads in Section 6.14 of the ES (Application Document Reference 6.1). The modelling results for individual receptors are presented on Drawings 6.1 to 6.35 (Application Document Reference 6.2) and tabulated in Appendix 6.6 (Application Document Reference 6.3).

3.22.3 The air quality assessment concludes that there is no significant effect predicted for the Scheme. As identified above, this assessment methodology is suitable for the assessment of effect on human health in regards to air quality, and therefore no significant effect on human health is anticipated due to air quality.

3.23 The Government primary driver for action on air quality is the impact it can have on health and the environment. The draft plans set out actions planned, being implemented and already taken at local

level, regional and national level to meet the annual and hourly EU nitrogen dioxide (NO2) limit values over the shortest possible time. Slough falls within the South East UK 0031 Zone, and has submitted 40

measures to improve NO2. The Government predict the South East Zone will be compliant with the EU limits by 2020 but only if Euro 6 emission standards perform as modelled. There is significant concern that real world Euro 6 passenger diesel car emissions standards are not performing as modelled in which case compliance may not be reached. It is noted the HE modelling attempts to verify modelled

results and then applies adjustments to represent the observed long term trend (LTT) profile of NO2 concentrations described in the IAN 170/12. The HE advised that the results are considered to present a realistic worst case scenario, as only a portion of the full anticipated improvements in air quality by DEFRA guidance are assumed to occur in the Gap Analysis result in 2022 (year of operation).

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However, even applying this adjustment needs to be treated with caution because it is clear air quality is not improving at predicted rates and the trend is still continuing.

Highways England's Comment

3.23.1 Highways England disagrees that the adjustment presented in the air quality analysis should be treated with caution. Highways England considers that the results do present a realistic worst case scenario. Over the last few years, the rates of improvement anticipated by the Department for Environment, Food and Rural Affairs (“Defra”) have not been realised as quickly as anticipated. This is due to the dieselisation of the vehicle fleet to a greater extent than previously anticipated, with the associated higher emissions

of NOx and NO2, and also because of the gap between the anticipated laboratory based

rates of NOx emissions compared with real world rates of NOx emissions. Similarly, it is recognised that not all the improvements in Euro VI emissions in the future may be realised at the same rate as Defra projections.

3.23.2 IAN 170/12 v3 already makes allowances for Euro 6/VI vehicles performing differently between the laboratory testing and the real world.

3.23.3 The modelling undertaken for this assessment uses Defra’s published vehicle emission factors, background maps and associated tools. The Scheme assessment applies Highways England IAN 170/12 v3 (‘Updated air quality advice on the assessment of

future NOx and NO2 projections for users of DMRB Volume 11, Section 3, Part 1 ‘Air

Quality’) and long term trends (“LTTE6”) spreadsheet version 1.1, which is the updated interim LTT curve issued for use in highways air quality assessments for Highways England schemes in 2014. This process is also known as gap analysis. This is described in paragraphs 6.2.57 to 6.2.60 of the ES (Application Document Reference 6-1).

3.23.4 In developing the projection factors for IAN 170/12 v3 (LTTE6), Highways England took

into account long term measured trends of NOx and NO2 (LTT) as well as the emission projections from Defra’s emission factor toolkit ("EFT"), based on only improvements in emissions attributed to Euro 6/VI vehicles and their penetration into the UK fleet up to 2030 (E6 Only).

3.23.5 The measured NOx and NO2 trends were based on monitoring data collected before the introduction of Euro 6/VI vehicles on to the UK road network, and consequently the monitoring data doesn’t record the impact of Euro 6/VI emissions. Recent emission testing for Euro 6/VI vehicles indicates that whilst measured emissions may be higher, they are lower than Euro 4/IV and Euro 5/V emission measurements. Consequently this

Deadline III - Response to Local Impact Reports 36 Highways England

is likely to lead to reduction in emissions over time as more Euro 6/VI vehicles enter the national fleet. (International Council on Clean Transportation)1.

Highways England Figure 1 - Rates of NO2 Change Informing IAN 170/12 v3

1.10

1.00

0.90 LTT

0.80

0.70 LTTE6

0.60

0.50 E6 Only

0.40

0.30 EFT

0.20

0.10

0.00

2008

2009

2010

2011

2012

2013

2014

2015

2016

2017

2018

2019

2020

2021

2022

2023

2024

2025

2026

2027

2028

2029 2030 EFT v5.2c Assumed Benefits from Euro 6 Vehicles only LTT Midpoint

3.23.6 Highways England has adopted a precautionary approach where future changes in NO2 concentrations would lie between the pessimistic (LTT) and optimistic future projections (E6 Only). It is difficult to estimate precisely where the balance lies in defining the trend

line LTTE6, especially on a timescale where the end point is as far away as 2030. Assuming a balance between the two extremes is a prudent way of describing a reasoned

NOx and NO2 trend line up to 2030 that could be applied to scheme assessments. Highways England keeps this information under review as new evidence emerges on measured vehicle emissions, including Euro 6/VI vehicles.

3.23.7 In this approach, all modelling is undertaken consistent with Defra emission rates and associated local air quality management tools. The LTT rates of improvement are applied to post-processed Defra based predictions to provide a more conservative set of results.

3.23.8 It should also be noted that any gap in laboratory testing cycles used to determine vehicle emissions and real world driving cycles will be captured through the air quality

1 http://www.theicct.org/sites/default/files/publications/ICCT_PEMS-study_diesel-cars_20141013.pdf

Deadline III - Response to Local Impact Reports 37 Highways England

modelling verification procedures. This approach will capture the gap between laboratory performance and real world emissions across a range of Euro standards.

3.23.9 In the model verification approach, air quality modelling predictions for a baseline year are compared to air quality monitoring results. In this approach, variances in the pollutant concentration between those predicted by modelling and those actually monitored can be identified and corrected. This verification approach will correct for the gap between laboratory and real world driving conditions, along with other aspects of the modelling approach. The verification approach is described in Appendix 6.4 of the ES (Application Document Reference 6-3).

3.24 SBC has recently secured funding from DEFRA to develop a low emission strategy which it is due to publish in Spring 2016. The strategy is aimed at reducing the NOx emissions from road transport

within the Borough. The objective is to comply with all NO2 Limits by 2020 (10 years after we should be complying with the EU limits). Slough has 3 other AQMAs located along the A4 and A355 and the impact of increasing capacity on the M4 needs to be assessed in relation to its likely effect on traffic on the local road network. There is no traffic data reported within the ES section 6.9.15 (an increase of 11,700 AADT on M4) and no details relating to impact of traffic on the local road network within Slough as a result of the Scheme. Thus no evaluation of the air quality impacts on the local road network has, as far as SBC is aware, been undertaken by HE (see 5.7). This is considered by SBC to be a major failing.

Highways England's Comment

3.24.1 Highways England disagrees that there has been any failing in the assessment of air quality impacts on the local road network, let alone a "major failing". While traffic data is not reported in every section of the ES, traffic data is an important component of almost every assessment carried out for the ES. The approach to the calculation of the traffic data used for assessment purposes are provided in section 6.7 of the Traffic Forecasting Report, which was provided at Appendix 1 to the Response to Relevant Representations at Deadline I. The details relating to the impact of traffic on the local road network, including Slough, as a result of the Scheme are at paragraph 13.8.6 of Chapter 13 of the ES.

3.24.2 The air quality assessment for the Scheme is provided in Chapter 6 of the ES (Application Document Reference 6-1). The methodology for determining the local air quality study area is prescribed by Design Manual for Roads and Bridges and set out in paragraph 6.2.31, bullet points a) through to e) of the ES (Application Document Reference 6-1). These criteria are used to identify whether significant changes in air quality are likely. If a criterion is not met or exceeded, then a significant change in air

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quality is not anticipated. Where these criteria have been met, sensitive receptors on those roads have been assessed.

3.24.3 The overall air quality study area for the local operational assessment is shown on Drawing 6.0 (Application Document Reference 6-2) as represented by the red lines (“significantly affected links”).

3.24.4 With the exception of the M4 and its slip roads, no other roads within Slough Borough Council’s administrative area, including those identified in the AQMAs above, were predicted to meet these criteria for potentially significant change in traffic flows, and therefore detailed modelling of other roads in the area was not required within the air quality assessment for the Scheme. There is therefore no failing in the air quality assessment undertaken for the Scheme as it is not necessary to further assess the local road network within SBC's administrative area.

3.25 As stated the South East Zone within which the Scheme mostly falls is predicted to be compliant by 2020, however the air quality assessment of the Scheme during year of operation 2022 indicates some

receptors may experience a breach of the annual EU nitrogen dioxide (NO2) limit, including within the SBC AQMA 1: this is very concerning.

Highways England's Comment

3.25.1 This assessment considers air quality objective values and not EU Limit Values. As such, where a change in concentration results in a predicted concentration at a sensitive receptor, this does not represent a breach of an EU Limit Value as compliance with EU Limit Values is only considered against the Automatic Urban and Rural Monitoring Network and the Pollution Climate Mapping models. The risk that the Scheme adversely affects compliance with EU Limit Values (i.e. a delay in compliance of a zone or making a compliant zone non-compliant) has been considered, as described above in paragraphs 3.18.1 to 3.18.13, and this is not the case

3.26 SBC are even more concerned that HE considers the impact on those residents exposed to breaches of the EU Limit at the year of opening (2022) not to be significant because they are applying their own ‘non-statutory’ ‘Interim Advice Note 174/13 Updated Advice for evaluating significant local air quality effects for users of BMRB Volume 11, Section 3, Part 1 ‘Air Quality (HA207/07)’. SBC believes this advice note does not adequately address the policy changes within NNNPS and more importantly the more urgent requirements under the DEFRA Draft Action Plan to reach compliance with the EU

Directive with respect to compliance of exposure to annual concentrations of nitrogen dioxide (NO2) limit values in the shortest possible time.

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3.27 Therefore the HE conclusion and Evidence in Support of Professional Judgement covered within Section 6.15.16 is challenged. The principal basis of the HE ‘significance test’ relates to the relatively small number of residents exposed to breaches of the Air Quality Objective (including (Sindlesham, Emmbrook, Dorney Reach, Lane End, Chalvey, Upton, Harlington, Brentford and Chiswick at the time of opening, 2022: a total of 18 residential receptors but with 11 of these receptors within Slough) and the medium to small ‘detrimental’ magnitude of change of the limit value. The main concern is that this is a limit value that should have be complied within in 2010. The HE is proposing no mitigation and SBC does not consider that this is an acceptable way of assessing significance, particularly with regards to the Government’s recent publication of draft action plans (currently under consultation) to

achieve NO2 compliance in the shortest possible time.

Highways England's Comment

3.27.1 Highways England disagrees with SBC's contention that the IANs do not adequately address recent policy changes as these IANs were developed to address the requirements of the NPS NN. . The suitability of the IANs for Highways England schemes has been accepted by the Secretary of State.

3.27.2 Highways England considers that the conclusions in Chapter 6 of the ES are sound. The professional judgement presented in 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1) considers predicted air quality effects against air quality objective values.

3.27.3 Highways England considers that the conclusions in Chapter 6 of the ES are sound. The professional judgement presented in 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1) addresses predicted air quality effects against air quality objective values.

3.27.4 EU Limit Values, as discussed in paragraphs 3.18.1 to 3.18.13 above, are considered following the methodology set out in Interim Advice Note 175/13. This assessment concluded that there was a low risk of the Scheme affecting compliance with the Directive.

3.27.5 The compliance risk assessment undertaken for the Scheme will not affect the timescales for the dates of compliance for any of the zones within which the Scheme or the wider local operational air quality study area is located.

3.27.6 This assessment considers air quality objective values and not EU Limit Values. As such, where a change in concentration results in a predicted concentration at a sensitive receptor, this does not represent a breach of an EU Limit Value as compliance with EU Limit Values is only considered against the Automatic Urban and Rural Monitoring

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Network and the Pollution Climate Mapping models. The risk that the Scheme adversely affects compliance with EU Limit Values (i.e. a delay in compliance of a zone or making a compliant zone non-compliant) in relation to the draft action plan has been considered, as described above in paragraphs 3.18.1 to 3.18.13, and this is not the case.

3.27.7 Therefore, the air quality effects of the Scheme have been considered for both air quality objectives and EU Limit Values, consistent with guidance and this is an appropriate approach to consider the overall significance of Scheme air quality effects.

3.27.8 Additionally, the Scheme is not anticipated to affect adversely the ability of the Government to discharge its responsibilities in relation to the Ambient Air Quality Directive and to also be consistent with the requirements of the specific air quality policy tests within the NN NPS, as outlined in paragraphs 6.18.1 to 6.18.10 of the ES.

3.28 SBC has suggested to HE that speed restrictions would be an appropriate mitigation measure to alleviate poor air quality. However HE’s response has been that this would not be compliant with their national policy. SBC takes the view that is an unsound justification for not considering speed control as an effective measure to alleviate poor air quality and that it is outweighed by NNNPS and Government policy.

Highways England's Comment

3.28.1 Highways England disagrees that air quality mitigation is necessary in relation to the Scheme. Whilst speed restrictions could be introduced as a mitigation measure for air quality as it does have the potential to reduce vehicle emissions along the Scheme route, significant adverse effects on air quality have not been predicted (as set out in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1)), and therefore mitigation measures such as this are not recommended for the Scheme. The introduction of measures such as this would also have the potential to divert traffic onto the local road network, with the associated risk of significant air quality effects on sensitive receptors along those routes.

3.29 HE state in Chapter 6: Table 6.22 that it will be difficult to avoid or reduce or repair or compensate for the effect of the Scheme as the M4 is as an existing route and therefore ‘traditional options to adjust alignment are limited’. However, SBC considers other options are available to mitigate the impact of the Scheme on residential receptors if they experience breaches of the EU limits at year of opening including:

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(a) Barrier treatment: changing the height of the barriers to reduce NO2 exposure to residential receptors to within EU limits;

(b) Variable speed controls to reduce NO2 exposure to residential receptors to within EU limits; and

(c) Boundary treatment of residential facades with carbon filtration ventilation systems to reduce

the impact of NO2 exposure where these are predicted to breach EU limits.

Highways England's Comment

3.29.2 In order for mitigation to be required a combination of air quality above air quality objectives with increases in pollutant concentrations of more than 0.4 µg/m3 at a number of sensitive receptors needs to be identified. In relation to the Scheme, whilst some areas were identified within SBC's administrative area to have concentrations of nitrogen dioxide above air quality objectives, only 11 out of 382 modelled receptors were predicted to have a small increase in nitrogen dioxide concentrations above the objective value.

3.29.3 As set out in the overall operational assessment of significance of the Scheme in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1), the air quality assessment does not predict a significant effect on sensitive receptors (which includes residential receptors) overall as a result of the Scheme, and therefore no air quality specific mitigation measures are proposed.

3.29.4 The SBC administrative area is within the South East zone for reporting compliance with EU Limit Values to the EC. In the Opening Year (2022) of the Scheme Defra does not predict exceedences of the EU Limit Value in the South East zone. A risk assessment has been undertaken using Highways England Interim Advice Note (“IAN”) 175/13 ‘Updated air quality advice on risk assessment related to compliance with the EU Directive on ambient air quality and on the production of Scheme Air Quality Action Plans for user of DMRB Volume 11, Section 3, Part 1 ‘Air Quality’. This risk assessment suggests that the Scheme will not affect the compliance of this zone.

3.29.5 Even if mitigation were required, the use of barriers (additional barriers or increasing the height of barriers) is not currently an approved technique for mitigating air quality effects on Highways England road schemes. This is because there is insufficient evidence as to the effectiveness of this type of measure. Therefore, based on both the viability of the measure and that the effect is not quantifiable, it is not an appropriate measure to use, especially as the Scheme is not anticipated to have a significant effect on air quality. .

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3.29.6 As identified in Highways England's response to paragraph 3.28 above, speed control as a measure to improve air quality is not in line with Highways England policy.

3.29.7 On the basis of the evaluation of significance as described above in paragraph 3.29.2, Highways England does not agree that boundary treatment of residential façade are

required as it is not necessary to reduce the impact of NO2 exposure as a result of the Scheme.

3.30 SBC has at its own expense requested its consultants Ricardo-AEA to consider mitigation options to protect Borough residents from the potential operational impacts of the Scheme in 2022. Ricardo-AEA have considered two scenarios:

(a) The height of barriers to afford protection to Slough residents so they are not exposed to

breaches of the EU limit for annual NO2;

(b) The average speed of traffic controlled through variable smart speed system to afford protection to Slough residents so they are no exposed to breaches of the EU limit for annual

NO2

3.31 It should be noted Ricardo do not have access to the HE base model and inputs so their modelling is not intended to recreate the HE model but is a quick assessment of the potential benefits of barriers

and, demonstrate the magnitude of change achieved in respect of NO2 reduction. It is to aid the ExA to

understand the effectiveness of barriers on residential exposure to elevate levels of NO2 in breach of EU limits. Further details on the use of barriers have been supplied by Ricardo-AEA and form Appendix 1.

3.32 The receptors affected within Slough are reported below in Table 2 as is the magnitude of change taken from the ES report Chapter 6 Air Quality and Appendix 6 Results for all receptors. Only the results relevant to Slough are reported. The IAQM guidance (again non – statutory guidance) for ‘Land-Use Planning & Development Control: Planning for Air Quality’ is guidance SBC uses for the assessment of significance of air quality impacts from proposed developments within its jurisdiction. It is acknowledged that this guidance is not intended to ‘replace’ existing guidance that HE have prepared in the form of a series of advice notes on assessing impacts and risk of non-compliance with limit values.

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Table 2: Slough Residential Receptors affected by breaches of the National Air Quality Objectives

year of opening (2022) annual mean NO2

Receptor 2013 LTT 2022 LTT 2022 Change HE SBC EU Limit ID Base NO Do- Do- (ìg/m3) Significance Value 2 Significance (ìg/m3) Minimum Something IAQM Breached IAN 174/13 NO2 (ìg/m3) NO2 (ìg/m3) guidance With Scheme X30 50.8 38.7 40.0 1.3 Small Moderate YES A247 51.6 39.4 40.7 1.3 Small Moderate YES A248 51.5 39.3 40.6 1.3 Small Moderate YES A249 51.6 39.4 40.8 1.4 Small Moderate YES A250 51.9 39.6 41.0 1.4 Small Moderate YES A251 52.2 39.9 41.2 1.3 Small Moderate YES A252 52.6 40.2 41.6 1.4 Small Moderate YES A253 53.1 40.6 42.0 1.4 Small Moderate YES A254 51.5 39.3 40.6 1.3 Small Moderate YES A322 53.6 40.8 42.5 1.8 Small Moderate YES A322_1 53.1 40.3 42.1 1.8 Small Moderate YES

Highways England's Comment

3.32.1 As identified by SBC, the IAQM guidance is not intended to replace the existing Highways England guidance, and indeed states this within the introductory section of the guidance: “This document has been developed for professionals operating within the planning system. It provides them with a means of reaching sound decisions, having regard to the air quality implications of development proposals. It also is anticipated that developers will be better able to understand what will make a proposal more likely to succeed. This guidance, of itself, can have no formal or legal status and is not intended to replace other guidance. For example, industrial development regulated by the Environment Agency, and requiring an Environmental Permit, is subject to the Horizontal Guidance Note H11, while for major new road schemes, Highways England has prepared a series of advice notes on assessing impacts and risk of non-compliance with limit values.”

3.32.2 The use of Highways England’s Interim Advice Note 174/13 ‘Updated advice for evaluating significant local air quality effects for users of DMRB Volume 11, Section 3, Part 1 ‘Air Quality (HA207/07)’ is therefore considered the appropriate methodology for the determination of significance for the Scheme.

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3.33 However, it is worth the ExA noting the descriptor of significance attached to both sets of non-statutory guidance and to understand why SBC are concerned about the magnitude changes in air quality levels predicted at the time of operation 2022 as well as the non-compliance with EU limits.

Highways England's Comment

3.33.1 Highways England consider that these issues have been addressed in its response to paragraph 3.18 above on the assessment of significance for highways schemes.

3.34 SBC consultants Ricardo-AEA modelling results are provided on a separate an excel datasheet (relating to monitoring positions and selected residential receptors) using different height barriers and speed scenarios in order to achieve compliance with EU limits (reductions are shown as % reduction

of NO2 for different barrier heights at different locations): see Appendix 2. These are summarised with in Table 3 below with respect to the receptors URS have identified that may be breached at year of opening (2022) within Slough. It can be seen from the results that if traffic is maintained at a free flowing speed of 50mph compliance will be achieved at all residential locations. It can be seen that 6m high barriers would afford sufficient protection to all residential properties affected by elevated levels

of NO2. The model can be refined further if HE release all model input files to SBC’s consultants so that maps can be reproduced with mitigation in place for different height barriers.

Table 3: Slough Residential Receptors affected by breaches of the National Air Quality Objectives

year of opening (2022) annual mean NO2 - barrier heights

Receptor Site Details 2013 LTT 2022 LTT 2022 Change Barrier Change EU Limit ID Base Do- Do-Something (ug/m3) Height to (ug/m3) Value 3 NO2 Minimum NO2 (ug/m ) reach Breached 3 (ug/m ) NO2 compliance With (ug/m3) with EU limit Mitigation X30 Paxton 50.8 38.7 40.0 1.3 2m -0.3 (39.7) NO Avenue A247 Spackmans 51.6 39.4 40.7 1.3 6m -1.3 (39.4) NO Way A248 Spackmans 51.5 39.3 40.6 1.3 6m -1.3 (39.3) NO Way A249 Spackmans 51.6 39.4 40.8 1.4 6m -1.3 NO Way A250 Spackmans 51.9 39.6 41.0 1.4 6m -1.3 NO Way A251 Spackmans 52.2 39.9 41.2 1.3 6m -1.3 NO Way A252 Spackmans 52.6 40.2 41.6 1.4 6m -1.3 NO Way A253 Spackmans 53.1 40.6 42.0 1.4 6m -1.3 NO Way

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A254 Spackmans 51.5 39.3 40.6 1.3 6m -1.3 NO Way A322 Winvale 53.6 40.8 42.5 1.8 6m -3.6 (38.9) NO A322_1 Winvale 53.1 40.3 42.1 1.8 6m -3.6 (38.5) NO

Highways England's Comment

3.34.1 A number of specific points have been modelled by Ricardo AEA along the M4 from junction 7 to the slip roads on the east side of junction 5. Many of these points correspond with the measurement locations along these sections. The remaining points appear to be indicative of sensitive receptor locations.

3.34.2 In Table 3, the potential effect at those receptors identified in the ES as being predicted to experience a change of more than 0.4 µg/m3 with predicted concentrations above 40 µg/m3 has been presented.

3.34.3 It is unclear how these numbers have been derived, based on the model outputs presented in Appendix 2 of Slough Borough Council’s Local Impact Report. Of the indicative points presented in Table 2, Roadside 17 is close to receptor point A253 and Roadside 15 is close to A322_1. The remaining receptors are not represented in the indicative locations presented in Appendix 2, and although receptors A247-A254 are in a row along one side of junction 6, there are no indicative points on the other side of the junction near receptor X30. As co-ordinates for each receptor point are presented in Appendix 6.6 of the ES (Application Document Reference 6-3), it is unclear why the specific receptors of concern were not modelled, or if they were, why these results are not presented in Appendix 2 of Slough Borough Council’s Local Impact Report.

3.34.4 It is also unclear what year the predicted results presented in Appendix 2 of Slough Borough Council’s Local Impact Report represent. The use of the title “base” implies a current year (2013/2014); however, if that is the case then these results are considerably lower than those predicted in the air quality assessment presented in the ES (Application Document Reference 6-1). If they represent the Opening Year (2022), then Roadside 17 is notably lower than A253 (6.5-8 µg/m3 compared to Do Minimum/Do Something), and Roadside 15 is a little higher than A322_1 (+3-5 µg/m3 compared to Do Something/Do Minimum). At other indicative locations, the difference compared to the receptors identified in the ES is as much as 18.9 µg/m3. For the two receptor points identified above as being approximately indicative of receptors identified in the ES, a comparison of numbers is presented below:

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Slough LIR Slough LIR ES 2013 2022 DM 2022 DS Receptor Point “Base” NO2 Receptor Base NO2 NO2 NO2 (µg/m3) Point (µg/m3) (µg/m3) (µg/m3) Roadside 17 34.0 A253 53.1 40.6 42.0 Roadside 15 45.2 A322_1 53.1 40.3 42.1

3.34.5 The potential benefits of 50mph speed control and high barriers for air quality based on the modelling undertaken by SBC's consultants is discussed in responses to the Appendices below.

3.34.6 In summary, many of the benefits identified in the Appendices and presented here are embedded in the Scheme. It is not necessary to apply them directly, since they are likely to be achieved through speed controls that may be present during the peak hours with the Scheme in operation.

3.34.7 Similarly, noise barriers are currently in place along the M4 and additional barriers are proposed for noise mitigation already and therefore the types of benefits suggested may already be achieved. These barriers are identified in detail in the responses to the Appendices below.

3.34.8 On the basis that the above benefits are already likely to be realised by the Scheme, no significant benefit is considered to be gained from any further model refinements by any party.

3.35 SBC respectfully requests that the ExA gives due consideration to these mitigation options (use of barriers and/or speed control) and considers applying them within the DCO.

Highways England's Comment

3.35.1 As set out above in the response to paragraph 3.29 above, Highways England considers that the use of barriers and/or speed controls are not mitigation options which could, or should, be applied to the Scheme.

3.35.2 The use of barriers is not currently an approved technique for mitigating air quality effects on Highways England road schemes. This is because there is insufficient evidence as to the effectiveness of this type of measure. Therefore, based on both the viability of the measure and that the effect is not quantifiable, it is not an appropriate measure to use, especially as the Scheme is not anticipated to have a significant effect on air quality.

3.35.3 Speed controls such as those identified may be in use during the peak hours with the Scheme in operation. However, for the reasons set out above, the use of speed controls as air quality mitigation is not Highways England policy.

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3.35.4 The overall operational assessment of significance of the Scheme is set out in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1). The air quality assessment does not predict a significant effect on sensitive receptors as a result of the Scheme, and therefore no air quality specific mitigation measures are proposed.

3.35.5 Highways England's response to the results presented in Appendix 1 below provides a more detailed response on the modelling work that has been carried out by Ricardo AEA and the suitability of these measures for mitigation purposes.

3.36 Finally, with respect of operational impacts from the M4 Smart Motorway SBC is of the view that HE should install a continuous N0x analyser at an agreed location within the Borough, close to its

residential receptors and the M4 (within AQMA 1) to monitor NOx and NO2 levels over a minimum period of 10 years from the date of consent to determine compliance with the UK National Air Quality Objectives. The ExA is requested to give due consideration to this requirement.

Highways England's Comment

3.36.1 As the air quality assessment does not predict a significant effect on sensitive receptors as a result of the Scheme, as set out in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1), Highways England does not believe that additional continuous monitoring data collection is required.

3.37 HE has a duty to ensure the impact of its strategic road network does not give rise to harm to public health and shall seek compliance with the EU limit values within the shortest possible time.

Highways England's Comment

3.37.1 The legal framework under which Highways England operates, as a government-owned strategic highways company is provided for by the Department for Transport. Highways England is therefore subject to extensive existing legislation on environmental issues, including the continued need for major road improvement schemes to go through a robust environmental assessment.

3.37.2 Compliance with statutory EU air quality limit values sits with Central Government, and not specifically with Highways England. Highways England's responses above set out the position that the Scheme will have no affect on achieving compliance with EU limit values.

3.37.3 For the reasons set out in the ES and in the reasons set out in the responses in this Local Impact Report, Highways England considers that the Scheme does not give rise to harm

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to public health. The response of Highways England above address public health, and note the conclusions of the HIA.

Construction Phase

3.38 The HE assessment methodology uses DMRB guidance to assess significant effects. SBC would advocate the use of IAQM Guidance on the assessment of dust from demolition and construction and recommend this approach be used to inform the final Construction and Environmental Management Plan (CEMP).

Highways England's Comment

3.38.1 Highways England does not consider that there is any reason why Institute of Air Quality Management (“IAQM”) guidance on the assessment of dust from demolition and construction sites should be used in preference to the methodology set out in the Design Manual for Roads and Bridges to consider dust during construction of the Scheme.

3.38.2 However, as stated in paragraph 1.10 of Appendix 6.3 of the ES (Application Document Reference 6-3), the recommended mitigation measures for potential air quality effects are based on those presented in the IAQM guidance on the assessment of dust from demolition and construction sites. These measures have also been included within the Outline Construction Environmental Management Plan (Appendix 4.2A of the ES) (Application Document Reference 6-3), which is secured under Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

3.39 The consideration of construction dust is based on the approach set out in DMRB. Sensitive receptors located along the Scheme that may be adversely affected during the construction phase have been identified. Where there are sensitive receptors within 200m of construction compounds or bridge works, additional site specific mitigation measures have been recommended (see Appendix 6.1, table 6.1.2) and this is acceptable.

Highways England's Comment

3.39.1 Highways England notes SBC's acceptance of the construction dust methodology and proposed mitigation measures and do not proposed to comment further.

3.40 Preliminary estimates of the construction traffic presented in the EDR indicate that on average it is expected that there will be an additional 150 HGVs on the local highway network daily, across the length of the Scheme route and between any construction compounds used. The HE criterion for a potentially affected local route in relation to construction HGV traffic is a change of more than 200

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HGVs per day. The additional number of HGV movements predicted for the Scheme is below this threshold and is not considered therefore by HE to be high enough to have the potential to cause a significant adverse effect at any sensitive receptors. Therefore, construction phase emissions from additional HGV movements have not considered further within HE’s assessment because it is concluded that the effect on sensitive receptors will be not significant.

3.41 SBC does not accept this position with respect to construction HGV movements within Slough’s AQMAs. Proposed Compound 9 has been sited within AQMA 2 Brands Hill and SBC is concerned that HGV traffic generated by this site would further deteriorate air quality levels within the Brands Hill area and jeopardise compliance by 2020. SBC therefore considers that Compound 9 should be removed from the list of potential compounds on air quality grounds.

3.42 SBC considers that all construction site traffic (HDVs) should be Euro VI compliant and LDVs Euro 6 compliant with 10% plugged in and electric hybrid vehicles to be used. SBC would expect non-road mobile construction machinery to comply with London NRMM standards for emissions.

Highways England's Comment

3.42.1 In response to paragraph 3.41 and 3.42 above, Highways England adopted the criteria set out in Design Manual for Roads and Bridges, Volume 11 Environmental Assessment, Section 3 Environmental Assessment Techniques, Part 1 Air Quality (HA 207/07). This provides that a significant air quality effect is only anticipated for an increase in the number of HGVs by 200 HGV movements per day. Below this number, a significant effect on air quality would not be anticipated.

3.42.2 As the number of HGVs predicted to be generated by Construction Compound 9 is below this 200 HGV criteria a detailed assessment of air quality effects is not required, as a significant effect is not anticipated and therefore it is not considered that this compound should be removed from the Scheme on air quality grounds.

3.42.3 Highways England disagrees that all construction site traffic (HDVs) should be Euro VI compliant and LDVs Euro 6 compliant with 10% plugged in and electric hybrid vehicles. This is because the plant and vehicles available and appropriate for use of the Scheme cannot be guaranteed to meet these standards whilst performing the specialist roiles for which they are designed.

3.43 In relation to the ExA’s question about the 200m study area for construction phase traffic effects SBC would expect this buffer to extend around the construction compounds and along construction routes along the local road network.

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Highways England's Comment

3.43.1 The 200m buffer, which has been used to identify sensitive receptor locations for further assessment, was measured from the centreline of any affected roads.

3.43.2 The 200m buffer is based on advice provided in Design Manual for Roads and Bridges, Volume 11 Environmental Assessment, Section 3 Environmental Assessment Techniques, Part 1 Air Quality (HA 207/07) where it is stated that “Only properties and Designated Sites within 200 m of roads affected by the project need be considered.”

3.43.3 Following a review of the traffic information available for the construction phase, it was confirmed that quantitative air quality modelling was not required for either the construction phase HGV assessment (paragraphs 6.2.48-6.2.50 of the ES (Application Document Reference 6-1)) or construction phase traffic management (paragraph 6.2.51 of the ES (Application Document Reference 6-1)). Therefore, the 200m buffer from road centrelines that would be used to identify a study area and sensitive receptors has not been required in respect of construction compounds and along construction routes along the local road network as no such assessment was required.

Noise and vibration

Operational Scheme

3.44 Road traffic noise is the most pervasive environmental noise source in the UK and affects more than 92% of dwellings in England and Wales, 2% are affected by motorway noise, and prolonged exposure to high levels of road traffic noise can give cause to harm to public health through impact on cognitive processing and learning, particularly children, heightened annoyance, anxiety and stress which may lead to cardiovascular disease.

Highways England's Comment

3.44.1 Highways England agrees with this statement.

3.45 The European Noise Directive (2002/49/EC) aims are to “define a common approach intended to avoid, prevent or reduce on a prioritised basis the harmful effects, including annoyance, due to the exposure to environmental noise”. The Directive Member States are to monitor environmental noise

problems (using the Lden and Lnight), informing and consulting the public about noise exposure and its effects, addressing local noise issues (no limit value is currently defined, unlike for air quality) and developing a long-term EU strategy (principally aimed at reducing the number of people affected by noise in the longer term). Member States are required to draw up ‘strategic noise maps for major roads, railways, airports and agglomerations. These were enshrined within English Legislation under the Environmental Noise (England) Regulations 2006, as amended.

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Highways England's Comment

3.45.1 Highways England agrees with this statement.

3.46 For new or improved highways, the Land Compensation Act 1973 allowed regulations to be promulgated to provide compensation for dwellings affected by increased noise. These regulations are the Noise Insulation Regulations 1975, as amended 1988. If certain criteria are met, the highway authority must offer secondary glazing and alternative ventilation for habitable rooms of dwellings so affected. This relates to new highway or altered highways where additional carriageway is being constructed. Properties within 300m of the highway will be eligible if the use of a highway causes or is

expected to cause noise at a level not less than the specified level L 10 (18-hour) of 68dB(A) if:

(a) the relevant noise level is greater by at least 1dB(A) than the prevailing noise level and is not less than the specified level, and

(b) noise caused or expected to be caused by traffic using or expected to use that highway makes an effective contribution to the relevant noise level of at least 1dB(A).

3.47 DEFRA has also adopted a Noise Action Plan to reduce road noise (including major roads. The Action Plan aims to promote good health and good quality of life (wellbeing) through the effective management of noise. This Action Plan will be relevant to highways authorities, including HE and it is intended that it will assist the management of environmental noise in the context of Government policy on sustainable development. It has been estimated that the approximate number of people associated with the Important Areas (noise “hotspots”) identified through the process described in the Action Plan for the major roads outside agglomerations is just under 51,000. However the Important Area is not defined but is likely to be close to the specified level quote above. It is noted the last round of noise mapping took place in 2012 and the next round in 2017 will need to take account of the increase capacity on the M4 when it is fully operational in 2022.

Highways England's Comment

3.47.1 Highways England agrees generally with these statements, although the reference to the 2017 noise mapping is open to question. The Scheme will be under construction at that time (if development consent is granted) and Defra will need to decide how the Scheme is taken into account in the 2017 mapping.

3.48 The M4 has been strategically noise mapped and there are a number of noise hotspots identified these are referred to under DEFRA guidance ‘Important Areas’. Within the Slough jurisdiction there are 8 ‘Important Areas’. HE has submitted plans to reduce the road traffic noise (including the use of noise barriers, and low noise surfacing).

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Highways England's Comment

3.48.1 The Important Areas on the M4 between Junction 3 and Junction 12 were included in the noise and vibration assessment for the Scheme. The Noise Action Plans for these Important Areas (including those in the Slough area) were taken into account in the development of the mitigation for the Scheme as explained in Table 12.10 of the ES (Application Document Reference 6-1).

3.49 It is noted that calculated noise levels within Slough are quite high: M12 Hoylake Close is calculated

to have L 10 (18-hour) of 69dB(A); M13 Cooper Way to have L 10 (18-hour) of 63dB(A); M14 Winvale to have

L 10 (18-hour) of 66dB(A); and M17 Severn Crescent to have L 10 (18-hour) of 70dB(A). The monitored noise levels are within 1Db at Winvale and Severn Crescent. The difference at Cooper Way and Hoylake Close suggests the monitoring location was not appropriate or shielded from road traffic noise. This does raise issues over the robustness of the noise model used.

Highways England's Comment

3.49.1 Highways England does not consider that the issues identified by SBC raise any concerns in relation to the robustness of the noise model used in the assessment. The differences between the measured noise levels and the calculated noise levels are discussed in paragraphs 12.4.17 to 12.4.19 in Chapter 12 of the ES (Application Document Reference 6-1). Inevitably there will be greater differences at some locations than at others for a range of reasons, including:

a) Measured noise levels are based on the traffic conditions prevailing during the measurement period. Whilst every effort is made to ensure traffic is free flowing during the measurement period, localised short term variations may affect the measured noise levels. Also, traffic flow rates may vary from day to day, which will affect the measured noise levels. The calculated noise levels are based on Annual Average Weekday Traffic (AAWT).

b) Measured noise levels are affected by the prevailing weather conditions during the measurement period. Whilst every effort is made to ensure that weather conditions are suitable for the measurements, short term variations may affect the measured noise levels. The calculation of noise levels assumes a moderate adverse wind blowing from the motorway to the monitoring location.

c) At some locations, prevailing noise levels may vary significantly over short distances, in particular, close to the motorway, or where complex shielding effects

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occur. Whilst every effort is made to match the measurement location and the calculation location, minor errors may result in differences in noise levels.

3.49.2 An assessment of the robustness of the noise model is made, which is based on the overall “fit” of the calculated noise levels to the measured noise levels. As stated in paragraph 12.4.19 in Chapter 12 of the ES , it is concluded that the noise model is robust and can be employed to calculate accurately the changes in noise levels and annoyance.

3.50 The World Health Organisation (WHO) has recommended a night time noise guidelines of Lnight,

outside 40 dB and an interim target of Lnight, outside 55 dB. The latest DEFRA Action Plan advises that

just less than 1 million people in England experience road traffic noise Lnight, outside above 55 dB. The

onset of significant community annoyance in the daytime is observed above levels of Leq, 16 hours 55 dB. The DEFRA Action Plan identifies more than 2 million people experience road noise above this level.

Highways England's Comment

3.50.1 Highways England does not disagree with this statement.

3.51 Exposure to elevated levels of road traffic noise directly links to public health outcomes. HE needs to ensure that if the Scheme leads to an increase in noise levels above EU limits, mitigation is required to prevent unacceptable exposure to residents.

Highways England's Comment

3.51.1 Highways England agrees that if the Scheme were to raise noise levels above EU limits, mitigation may be required. However, this is not the case. The short term changes in noise levels within the Scheme corridor are provided in Drawing 12.4 of the ES (Application Document Reference 6-2). The long term changes in noise levels within the Scheme corridor are provided in Drawing 12.5 of the ES (Application Document Reference 6-2). Sheets 10, 11 and 12 are relevant to the Slough area.

3.51.2 The magnitude of impact for the Scheme is minor beneficial in the short term and negligible in the long term. The significance of effect during the operation of the Scheme is assessed as slight beneficial in the short term and neutral in the long term, with the vast majority of the Scheme corridor experiencing negligible or minor reductions in noise levels with the Scheme in operation (see paragraph 12.4.110 of the ES) (Application Document Reference 6-1). These noise reductions are shown in Drawing 12.4 for the short term, and in Drawing 12.5 for the long term (Application Document Reference 6-2). Sheets 10, 11 and 12 are relevant to the Slough area. Where there are negligible noise increases (rather than noise decreases) to sensitive receptors, these are to areas

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bordering other road links, not the Scheme, and will occur if the Scheme were not developed, as can be seen in Drawing 12.3 of the ES (Application Document Reference 6-2).

3.52 It is noted within the noise study that 44,259 residential properties and 69 schools, 52 places of worship, 59 community facilities and 1 hospital lie within 1km of the Scheme. All of these are considered sensitive receptors. A do-nothing and do-something assessment has been undertaken to compare the existing with proposed scheme. It is noted the EU does not specify noise limits.

Highways England's Comment

3.52.1 Highways England agrees with this statement.

3.53 SBC assumes the entire stretch of the M4 between junction 3 and 12 would be resurfaced with a low- noise surface rather than just the re-surfacing of the existing hard shoulder and far-side lane. Confirmation of this is requested.

Highways England's Comment

3.53.1 Highways England confirms that all lanes of both carriageways will be resurfaced with a low noise surface between Junction 3 and Junction 12.

3.54 Future baseline conditions consider ‘do minimum’ traffic noise levels and the change from the opening year (2022) to future assessment year (2037). It is noted when comparing the long term change in traffic noise levels between 2022 and 2037 there is an increase in daytime noise level between 0.1-2.9

dB L 10 (18-hour) at 2,954 dwellings and at night-time Lnight, outside of 1179 dwellings. Most dwellings are expected by HE to experience a slight improvement in traffic noise because of low-noise surfaces. SBC is not convinced on this point.

Highways England's Comment

3.54.1 Highways England agrees with the stated numbers of properties experiencing daytime and night-time noise level increases (taken from Table 12.12 in Chapter 12 of the ES (Application Document Reference 6-1)) and with the statement “Most dwellings are expected by HE to experience a slight improvement in traffic noise because of low-noise surfaces”.

3.54.2 Slough Borough Council does not provide any supporting evidence to justify the statement “SBC is not convinced on this point.”. Highways England provides the following information in support of the results of the noise assessment, which show a slight improvement in traffic noise.

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3.54.3 The noise assessment employed the procedures in the Design Manual for Roads and Bridges ("DMRB"), as required for the assessment of road schemes. Noise levels were calculated using the Calculation of Road Traffic Noise ("CRTN"), which is the standard method for the calculation of road traffic noise levels in the UK and which is the method required by DMRB.

3.54.4 The calculations were carried out in a commercial software package which implements the CRTN methodology. Within the software package, a detailed model of the existing M4 motorway between junctions 3 and 12, the proposed Scheme and the surrounding area (out to a distance of 2 km) was developed. The model included the following:

 All relevant roads within 2 km of the M4 motorway;

 All buildings (residential and non-residential) within 2 km of the M4 motorway;

 All existing and proposed noise barriers;

 Detailed ground elevation data for the Scheme, the existing M4 motorway and the surroundings out to a distance of 2 km (ensuring that all roads, buildings and barriers were set at the correct heights); and

 Ground absorption data for areas of hard ground (i.e. sound reflective) and areas of soft ground (i.e. sound absorbing).

3.54.5 Additionally, all roads in the model were provided with a “surface correction” to allow for the noise effects of standard road surfaces and low noise road surfaces. This included the existing M4 motorway, which is a mixture of stretches of low noise surfacing and stretches of standard hot rolled asphalt ("HRA").

3.54.6 DMRB provides the surface correction for thin surfacing systems (which are low noise surfaces and which are to be used on the motorway) (DMRB Volume 11, Section 3, Part 7, paragraphs A4.18 to A4.29). The surface correction to be used is -3.5 dB.

3.54.7 Research has indicated that, when new, low noise surfaces provided on average between 4 and 6 dB(A) benefit over tested HRA surfaces. In spite of the better acoustic durability of the HRA surfaces, low noise surfaces still outperformed the HRA surfaces by 1 to 3 dB(A) after 10 years (TRL Report PPR485: The Performance of Quieter Surfaces Over Time, 2010).

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3.54.8 The -3.5 dB correction for a low noise surface, as prescribed in DMRB, is a reasonable average over the life of the surface for calculation and assessment purposes.

3.54.9 It is assumed in the noise assessment that the complete extent of the M4 motorway between junctions 3 and 12 will be resurfaced with a low noise surface at some time before 2037 if the Scheme did not go ahead (paragraph 12.2.53 of Chapter 12 of the ES (Application Document Reference 6-1)).

3.54.10 Given the above, it is considered that the calculations carried out for the noise assessment are robust and that the results reported in Table 12.12 in Chapter 12 of the ES (and associated Tables 12.16 and 12.17), which show negligible/minor noise reductions at the majority of receptors, are accurate (Application Document Reference 6-1)).

3.55 It is noted seven properties would experience a minor increase in road traffic noise levels as a result of the Scheme against the ‘do minimum scenario’ and 27% experience a negligible increase in noise when comparing the opening year of scheme with existing. When comparing 2037 (Scheme open 15 years) against the ‘do minimum’ of 2022, 29% of residents experience a negligible increase.

Highways England's Comment

3.55.1 Highways England disagrees with the figures presented by SBC. Table 12.16 of Chapter 12 of the ES (Application Document Reference 6-1), which presents the short term change in traffic noise levels resulting from the Scheme, shows that 2 residential properties are predicted to experience minor increases in traffic noise levels (1.0 to 2.9 dB) in the short term. A total of 505 residential properties are predicted to experience negligible increases in traffic noise levels (0.1 to 0.9 dB) in the short term, out of a total of 23,025 residential properties in the detailed study area. This is equivalent to just over 2% of the total number of properties.

3.55.2 Table 12.17 of Chapter 12 of the ES (Application Document Reference 6-1), which presents the long term change in traffic noise levels resulting from the Scheme, shows that a total of 4,590 residential properties are predicted to experience negligible increases in traffic noise levels (0.1 to 2.9 dB) in the long term, out of a total of 23,025 residential properties in the detailed study area. This is equivalent to just under 20% of the total number of properties.

3.56 Between Junction 7 and 6 there are 6,878 residential properties lying within 1km of the motorway. It is understood that one additional noise barrier is to be erected with 5 existing noise barriers and low

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noise surfaces of the carriageway already in place. The section between Junction 6 and 5 has 6,450 residential properties within 1km of the M4 and noise reduction measures appear to consist of 5 additional noise barriers and low noise surfacing of two sections of the carriageway. A total of 3,012 residential properties lie within 1km of the motorway between Junction 5 and 4b with measures focusing on 7 existing noise barriers and 5 sections with low-noise surfacing.

Highways England's Comment

Junction 7 to Junction 6

3.56.1 Highways England confirms that 6,878 residential properties have been identified within 1 km of the motorway between Junction 7 and Junction 6.

3.56.2 Highways England confirms that there are five existing noise barriers between Junction 7 and Junction 6 and that one additional noise barrier is proposed as part of the Scheme mitigation.

3.56.3 Highways England confirms that, whatever the existing type of road surface, a new low noise surface will be installed across all lanes of both carriageways along the complete extent of the Scheme (paragraph 12.9.12 of Chapter 12 of the ES (Application Document Reference 6-1)).

Junction 6 to Junction 5

3.56.4 Highways England confirms that 6,450 residential properties have been identified within 1 km of the motorway between Junction 6 and Junction 5.

3.56.5 Highways England confirms that there are seven existing noise barriers between Junction 6 and Junction 5 and that five additional noise barriers are proposed as part of the Scheme mitigation.

3.56.6 Highways England confirms that, whatever the existing type of road surface, a new low noise surface will be installed across all lanes of both carriageways along the complete extent of the Scheme (paragraph 12.10.12 of Chapter 12 of the ES (Application Document Reference 6-1)).

Junction 5 to Junction 4b

3.56.7 Highways England confirms that 3,102 residential properties (rather than 3,012) have been identified within 1 km of the motorway between Junction 5 and Junction 4b (paragraph 12.11.2 of Chapter 12 of the ES (Application Document Reference 6-1)).

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3.56.8 Highways England confirms that there are seven existing noise barriers between Junction 5 and Junction 4b. Four additional noise barriers are proposed as part of the Scheme mitigation (at Junction 5).

3.56.9 Highways England confirms that, whatever the existing type of road surface, a new low noise surface will be installed across all lanes of both carriageways along the complete extent of the Scheme (paragraph 12.11.11 of Chapter 12 of the ES (Application Document Reference 6-1)).

3.57 It is clear that the M4 with or without the Scheme exposes significant numbers of residents above the

WHO interim target of Lnight, outside 55 dB level; there is clear evidence of impacts to public health above this level. The motorway is noisy and has 8 Important Areas within the Slough jurisdiction that require noise mitigation even without the Scheme. There is a requirement on HE under the DEFRA Noise Action Plan to take steps to minimise noise in the Borough.

Highways England's Comment

3.57.1 The WHO interim target level of 55 dB LAeq,8h is referenced in Chapter 12 of the ES (Application Document Reference 6-1). Paragraphs 12.2.21 and 12.2.22 define SOAEL (Significant Observed Adverse Effect Level) and LOAEL (Lowest Observed Adverse Effect Level) values for road traffic noise. The

night-time SOAEL is set at the WHO interim target level of 55 dB LAeq,8h.. Table 12.18 in Chapter 12 of the ES shows the estimated number of residential properties within the Scheme study area at or above the SOAEL, with and without the Scheme. It can be seen that there will be a decrease in the number of properties at or above the daytime and night-time SOAEL with the Scheme, when compared to the baseline in 2022 (although note that Highways England acknowledges that there will be a comparable decrease in the long term if the Scheme did not go ahead).

3.57.2 The Important Areas (from the Round 1 strategic noise mapping) between Junction 3 and Junction 12 (including those in the SBC area) were taken into account in the noise assessment (Table 12.10 and paragraph 12.4.10 in Chapter 12 of the ES). The Noise Action Plans for these Important Areas were consulted. Those in the SBC area referenced the previous installation of noise barriers post 2006 and no further action was specified.

3.57.3 The noise and vibration assessment is reported in Chapter 12 of the ES (Application Document Reference 6-1). The magnitude of impact for the Scheme is minor beneficial in the short term and negligible in the long term. The significance of effect during the operation of the Scheme is assessed as

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slight beneficial in the short term and neutral in the long term, with the vast majority of the Scheme corridor experiencing negligible or minor reductions in noise levels with the Scheme in operation (see paragraph 12.4.110 of the ES) (Application Document Reference 6-1). These noise reductions are shown in Drawing 12.4 for the short term, and in Drawing 12.5 for the long term (Application Document Reference 6-2). Sheets 10, 11, 12 and 13 of the drawings are relevant to the Slough area.

3.57.4 Notwithstanding these noise reductions with the Scheme in operation, there is potential to further improve the noise climate within the Scheme corridor through enhanced mitigation, as noted in paragraph 12.4.112 of the ES (Application Document Reference 6-1). A qualitative appraisal of an enhanced mitigation strategy to achieve this is provided in Appendix 12.5 of the ES (Application Document Reference 6-3). This enhanced mitigation strategy comprises the provision of additional noise barriers, as outlined in Table A12.5.1 of Appendix 12.5 of the ES (Application Document Reference 6-3) and the replacement of some existing noise barriers with higher noise barriers as outlined in Table A12.5.2 of Appendix 12.5 of the ES (Application Document Reference 6-3).

3.57.5 The enhanced mitigation strategy outlined in Appendix 12.5 of the ES (Application Document Reference 6-3) was based on the identification of, and provision of additional mitigation to, those areas within the Scheme corridor experiencing noise levels at or above the daytime and night-time SOAEL (significant observed adverse effect level). The SOAEL and related parameters are discussed in paragraphs 12.1.19 to 12.1.24 of Chapter 12 of the ES and values are assigned for road traffic noise in paragraphs 12.2.21 and 12.2.22 of Chapter 12 of the ES (Application Document Reference 6-1).

3.57.6 The mitigation between Junction 7 and Junction 4b, covering the Slough area, is included in this enhanced mitigation study.

3.57.7 The effects of implementing this enhanced mitigation strategy have not been assessed in Chapter 12 of the ES (Application Document Reference 6-1). Hence, the assessment provided in Chapter 12 of the ES (which concludes that the vast majority of the Scheme corridor will experience noise reductions with the Scheme in operation) is very much a worst case.

3.57.8 Work is ongoing to provide a quantitative assessment of the enhanced mitigation strategy outlined in Appendix 12.5 of the ES (Application Document Reference 6-3). This comprises an iterative process which is

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employed to estimate the numbers of receptors experiencing specific reductions in noise levels (for an additional noise barrier, as detailed in Table A12.5.1 of Appendix 12.5 of the ES (Application Document Reference 6-3), or replacement of an existing barrier, as detailed in Table A12.5.2 of Appendix 12.5 (Application Document Reference 6-3)), monetising the benefits of these reductions in noise levels (as employed in TAG appraisal) and comparing this monetisation value with the cost of the mitigation to provide a cost benefit analysis. Thus, the lengths and heights of new barriers (if specified), and the heights of replacement barriers (if specified), will be optimised. The results of that assessment, and the results of the assessment of the landscape and visual impact of any additional noise barriers proposed, will be provided to the Examination in due course.

3.58 The following environmental noise information is required:

(a) clarification of all Slough residential properties that may be entitled to noise compensation or insulation under the Land Compensation Act 1973 and the Noise Insulation Regulations 19759, as amended 1988; and

(b) a significant number of properties are expected by HE to experience what is termed a negligible increase of more than 1dB as a result of the Scheme, but how many will also

experience the specified level of L 10 (18-hour) of 68dB(A)?

Highways England's Comment

Point (a)

3.58.2 The noise and vibration assessment, as provided in Chapter 12 of the ES (Application Document Reference 6-1) indicates that no properties will qualify for noise insulation under the Noise Insulation Regulations 1975 (as amended 1988).

Point (b)

3.58.3 Highways England does not accept that “a significant number of properties are expected by HE to experience what is termed a negligible increase of more than 1dB as a result of the Scheme”.

3.58.4 A negligible increase in noise level is defined differently for the short term and the long term. For the short term, a negligible increase is defined as < 1 dB, as shown in Table 12.7 of Chapter 12 of the ES (Application Document Reference

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6-1). For the long term, a negligible increase is defined as < 3 dB, as shown in Table 12.8 of Chapter 12 of the ES (Application Document Reference 6-1).

3.58.5 Table 12.16 of Chapter 12 of the ES shows that only two properties will experience an increase in noise level greater than, or equal to, 1 dB in the short term. The resultant noise levels with the Scheme in operation are less than 68

dB LA10,18h.

3.58.6 Table 12.17 of Chapter 12 of the ES shows that 4,590 properties will experience an increase in noise level between 0.1 and 2.9 dB in the long term with the Scheme in operation (no properties will experience noise increases greater than this). Of these, only 80 properties will experience an increase in noise level greater than, or equal to, 1 dB. Of those 80 properties, only 14

properties will experience noise levels greater than, or equal to, 68 dB LA10,18h with the Scheme in operation.

3.58.7 For comparison, Table 12.12 of the ES (Application Document Reference 6-1) shows that 2954 properties will experience an increase in noise level between 0.1 and 2.9 dB in the long term if the Scheme did not go ahead (no properties will experience noise increases greater than this). Of these, 47 properties will experience an increase in noise level greater than, or equal to, 1 dB. Of those 47 properties, 9 properties will experience noise levels greater than, or equal to,

68 dB LA10,18h.

3.58.8 Thus, it is considered that there is not a significant difference in noise level in the long term, with or without the Scheme. The properties experiencing noise level increases greater than, or equal to, 1 dB are in the vicinity of existing road links other than the Scheme and the noise increases are a result of changes in traffic flows on these links over the long term. They do not qualify for noise insulation under the Noise Insulation Regulations 1975 (as amended 1988).

Construction Phase

3.59 SBC notes the outline Construction Environmental Management Plan (CEMP) but is particularly concerned about the impact of piling operations (noise and vibration), night time noise impact from construction activities and dust impact to our residents in Slough and questions whether the outline CEMP as drafted is sufficiently robust on these issues. The HE detailed noise assessment of demolition, piling and construction is based on BS5228 guidance and references. A detailed noise management plan (page 88 to 99 of the Outline CEMP, Appendix 4.2A) includes noise limits and noise monitoring.

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Highways England's Comment

3.59.1 Highways England considers that the CEMP is sufficiently robust to manage noise and dust impacts from construction activities. As previously noted, the final CEMP is subject to approval by SBC. Once the contractor has developed the detailed construction programme and associated plant schedule, the likely noise and vibration effects will be verified, including those from operation of the construction compounds. This will include an appraisal of necessary night- time working and the associated noise and vibration effects.

3.59.2 The contractor will be required by the Construction Environmental Management Plan (“CEMP”) to employ best practicable means to minimise noise and vibration levels during the works. There will be close liaison between the contractor and Local Authority Environmental Health Officers, affected residents and commercial operations, to ensure that noise and vibration during construction are effectively managed. The contractor will enter into Section 61 Agreements (under the Control of Pollution Act 1974) with relevant local authorities. Noise and vibration limits will form part of these Section 61 Agreements.

3.59.3 The procedures for managing noise and vibration during construction, including a protocol for compliance monitoring, will be documented in the Construction Environmental Management Plan. An Outline Construction Environmental Management Plan was submitted in support of the Application (Appendix 4.2A of the ES) (Application Document Reference 6-3) and this will be finalised by the contractor, and agreed with relevant local authorities, prior to commencement of construction works (pursuant to Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1)).

3.60 In Appendix 12.3 (APP-349) ‘construction noise data and results’, the assessments suggest a number of Slough’s residential properties would be significantly affected by construction activity particularly in the evening and at night and this gives SBC concern. SBC would want to impose restrictions on evening and night-term working that could adversely harm residential amenities and seeks ways and means through the DCO process to enable such controls to be applied.

Highways England's Comment

3.60.1 Likely night-time works are listed in paragraph 12.4.42 of the ES (Application Document Reference 6-1). Night-time works specific to the mainline works are referenced in paragraph 12.4.54 of the ES (Application Document Reference 6- 1).

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3.60.2 The results provided in Appendix 12.3 of the ES (Application Document Reference 6-3) identify significant construction noise effects for the chosen receptors in the Slough area. However, as stated in paragraph 12.4.53 of Chapter 12 of the ES (Application Document Reference 6-1), those activities resulting in high noise levels are all dynamic in nature, as the works move along the Scheme, and these worst case noise levels will prevail for relatively short periods of time.

3.60.3 However, there may be other activities which the contractor requires to carry out at night for both safety and programme expediency (such as slip-form central reserve concrete safety barriers). These activities would be included in any applications for Section 61 consents under the Control of Pollution Act 1974.

3.60.4 The controls SBC request do not themselves form part of the DCO process, but the powers to impose reasonable restrictions where necessary are secured by the requirements attached to the draft DCO.

3.60.5 The requirements are provided in Schedule 2 of the Draft DCO (Application Document Reference 3-1). Requirement 8 relates to the Construction Environmental Management Plan (an Outline Construction Environmental Management Plan was submitted in support of the DCO Application at Appendix 4.2A of the ES (Application Document Reference 6-3)).

3.60.6 Requirement 8 states (in part):

 No part of the authorised development is to be carried out until a CEMP, substantially in accordance with the Outline CEMP, annexed to the Outline EMP (dated March 2015), has been submitted to and approved by the relevant planning authority.

 The construction of the authorised development must be carried out in accordance with the CEMP.

 The undertaker may modify the CEMP at any time after the authorised development has commenced and must notify Natural England of any modifications as far as they relate to protected species or protected sites.

3.60.7 Paragraph 5.2.1 of the Outline Construction Environmental Management Plan (Appendix 4.2A of the ES) (Application Document Reference 6-3) states that the contractor will seek to obtain consents from the relevant local authorities where necessary under Section 61 of the Control of Pollution Act 1974 for the proposed construction works, excluding non-intrusive surveys.

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3.60.8 Applications for Section 61 consents will include details on proposed working hours and construction activities to be carried out during those hours, including night-time works.

3.60.9 Any conditions included in consents / licences / permits will be documented in the final Construction Environmental Management Plan, pursuant to Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

Heritage assets

3.61 SBC notes that Table 7.3 of Chapter 7 APP-147 concludes that there would be slight adverse temporary and permanent impacts on the setting of Cippenham Court scheduled monument. This emphasises the need for appropriate mitigation of the works proposed at the Wood Lane overbridge (see paras 3.3, 3.4).

Highways England's Comment

3.61.1 Highways England disagrees that mitigation is required for the works proposed at the Wood Lane overbridge. Paragraph 7.9.11 of the ES (Application Document Reference 6- 1) notes that only a small portion of the Cippenham Court scheduled monument lies within the Scheme ZVI and any visual changes as a result of the replacement of the Wood Lane overbridge will be very limited. The magnitude of this impact is considered to be negligible. Paragraphs 7.9.7 and 7.9.8 of the ES note that no mitigation measures are considered necessary as the visual intrusion of the new structure is considered to be very limited for both the construction and operational phases.

4. ENGINEERING AND DESIGN

4.1 SBC has been consulted on the engineering and design of the Scheme and made comments during the consultation period (APP-096 Engineering & Design applies). Other comments are made below.

4.2 It is noted that draft DCO Requirement 6 gives scope for the design of the Scheme to be altered subject to approval of SBC as Local Planning Authority but the ExA has questioned its validity. SBC looks forward to clarification of this issue.

Highways England's Comment

4.2.1 Highways England addressed Requirement 6 in its response to the Examining Authority's First Written Questions, DCO8.22, and has nothing further to add here. Highways England's response was as follows:

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1. The development authorised by the DCO, if made, would be constrained by the power of deviation given by Article 6 as set out in the dDCO. As noted above, and as set out in paragraphs 5.10.1 and 5.10.2 of the ES, the scope of the power of deviation was specifically considered by Highways England’s expert professional team.

2. Effectively, the assessed, authorised Scheme is that shown on the works plans and described in the Draft DCO at Schedule 1. The design shown on the engineering drawings and sections (Application Document Reference 2.5-2.9), gantry drawings and the other documents references in requirement 6(1) is one set of variations within the proposed Scheme. As explained above in answer to DCO question 9.21, the development authorised by the dDCO is constrained by the power of deviation under Article 6. That power to deviate was assessed as part of the EIA for the Scheme (see paragraph 5.10.1-2 of the ES) and an alternative must be capable of being built within that assessed envelope, effectively a different design within the limits of the approved Scheme. This application relates to approval of a Scheme and one design, but not a limitation to that design.

3. As with Requirement 3, Requirement 6(1) and (2) can only be used to allow development that has been authorised by the DCO. It would be unlawful to authorise works going beyond the scope of the DCO as explained in answer to DCO question 8.20 and, accordingly, it would not be possible to authorise works that fell outside the scope of what had been assessed in the ES, and consequently approved under the DCO.

Motorway Junctions

4.3 In relation to Junction 7, SBC notes that the proposed works would result in a realignment of the Huntercombe overbridges eastwards. As the finished level of the bridges would be about 1.2m higher than the existing overbridges, the link road and approach embankment would also need to be realigned eastwards. The result would be to bring these structures closer to residential areas in Cippenham, the Mercian Way Recreation Ground and allotment. Given the engineering challenges in replacing the existing Junction 7 bridges whilst maintaining use of the Huntercombe Spur, no objection is raised to this in principle provided appropriate mitigation is put in place (see 3.3, 3.4)

Highways England's Comment

4.3.1 SBC's summary of the proposal to realign Huntercome Spur road at junction 7 is correct, the eastern parapet of the proposed replacement bridge is up to 20m further east than the eastern parapet of the existing bridge, and the proposed

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realignment of Huntercombe Spur road crosses over the M4 at a level approximately 1.2m higher than its existing alignment. This is illustrated on the Side Road Plan and Profile Drawings in Figure 4.2 of the Environmental Statement (“ES”) (Application Document Reference 6-2) and Huntercombe Spur Overbridge General Arrangement in Annex F3 of the Engineering and Design Report (“EDR”) (Application Document Reference 7-4).

4.3.2 However, it should be noted that no realignment is proposed for the junction 7 slip road closest to Cippenham, the east bound on slip. A retaining wall is included in the proposals to accommodate the realigned spur road without impacting the eastbound on slip. Proposed work in this area, including Spur Road realignment, bridge works and retaining wall are summarised in sections 7.6.20 to 7.6.24 of the EDR.

4.4 SBC understands that no significant works are proposed to Junction 6 and the associated bridges except for some widening of slip roads. At Junction 5 the symmetrical widening of the underbridges would be a major undertaking: SBC has no comment on the engineering design but comments are put forward in Section 3 on the environmental impact; in Section 5 on the traffic management and rights of way aspects; and in Section 8 on the relationship of these works with SBC’s SMaRT bus rapid transit scheme.

Highways England's Comment

4.4.1 SBC's summary of the proposals at junctions 6 and 5 are correct, the slip roads at each junction will be realigned to suit the proposed All Lane Running (“ALR”) configuration of the M4. Symmetrical widening is proposed through junction 5 which will require earthworks widening and structural widening of the interchange bridges and the interchange subway. This is illustrated in the Mainline General Arrangement Drawings and Underbridge General Arrangement Drawings in annexes F1 and F2 of the EDR.

Overbridges

4.5 The Scheme would mean the replacement of 4 overbridges within the Borough with varying impacts on residents, businesses and road users, especially during the construction phases.

4.6 SBC accepts that offline structures are the most practicable for the Wood Lane and Datchet Road and overbridges. No adverse comments are raised on the engineering designs provided that the horizontal and vertical profiles would satisfactorily tie in with those of the adjacent carriageways and that suitable provision is made for pedestrians and cyclists.

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Highways England's Comment

4.6.1 Highways England agrees that the proposed offline structures are the most practicable solution at Wood Lane and Datchet Road overbridges, and notes SBC's provisos..

4.6.2 The works are illustrated on the Side Road Plan and Profile Drawings in Figure 4.2 of the ES. The detailed design of each of these roads will ensure a smooth tie in to the existing carriageways at each end of the realignment works. The limits of deviation detailed in the draft Development Consent Order (“dDCO”) (Application Document Reference 3-1) Article 6 include sufficient flexibility in the design to ensure that this is possible.

4.6.3 The proposed new bridge at Wood Lane includes a 2.0m wide cycle way / foot way along the western side of Wood Lane to accommodate Bridleway Slough 17. The proposed bridge parapets are 1.8m high to provide safe containment of pedestrians, cyclists and equestrian users. Details of the proposed bridge are included on the Bridge General Arrangement Drawings in Annex F2 of the EDR (Application Document Reference 7-4). The alterations in the rights of way associated with the cycle way / foot way is shown on Sheet 5 of the Right of Way and Access Plans (“RoWA plans”) (Application Document Reference 2-4) and detailed in Schedule 3 of the dDCO. The realigned cycle way /foot way is also illustrated in the Side Road Plan and Profile Drawings (Application Document Reference 2-6).

4.6.4 The proposed new bridge at Datchet Road includes a 3.0m wide foot way along the western side of Datchet Road. The proposed bridge parapets are 1.4m high to provide safe containment of pedestrians and cyclists. Details of the proposed bridge are included on the Bridge General Arrangement Drawings in Annex F2 of the EDR (Application Document Reference 7-4). The alterations in the rights of way associated with the cycle way / foot way is shown on Sheet 7 of the RoWA plans and detailed in Schedule 3 of the dDCO. The realigned foot way is also illustrated in the Side Road Plan and Profile Drawings (Application Document 2.6).

4.7 Bridleway 17 SLO crosses the current Wood Lane overbridge and the new structure would need to be designed to appropriate standards for a bridleway, including parapets with a minimum height of 1.8m, and a footway of sufficient width to allow pedestrians to cross safely off-carriageway (The proposed design in APP-120 indicates two verges and further discussion is invited on these details).

Highways England's Comment

4.7.1 Highways England confirms that the proposed Wood Lane Road Overbridge has been designed to the appropriate standards for a bridleway, as noted in Highways England's

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response to paragraph 4.6 above. Highways England notes the request from SBC for discussion in relation to the details of the bridleway and its realignment.

4.8 Beyond the Slough boundary in Datchet Road there are currently laybys and stops for both northbound and southbound bus services. It is not clear to SBC what provision would be made by HE for their relocation as a result of the proposed bridge works.

Highways England's Comment

4.8.1 The proposed realignment of Datchet Road extends across the full length of each these laybys. The proposed works therefore include the reconstruction of each layby as close as practical to the existing location and to the same dimensions. This can be seen on Sheet 10 of the Side Road Plan and Profile Drawings (Application Document Reference 2-6).

4.9 The on-line replacement of the Oldway Lane and Old Slade overbridges will be disruptive to rights of way users (see 5.xx) but SBC makes no comments on the design of the new structures provided that sufficient arrangements are made for future rights of way use.

Highways England's Comment

4.9.1 Oldway Lane and Old Slade Lane overbridges are proposed as online replacements. Highways England proposals include sufficient arrangements for future use of the rights of way affected by the works. Details of the affected rights of way are shown on sheets 4 and 9 of the RoWA plans with further detail included in Schedules 3 and 4 of the draft DCO.

4.9.2 Oldway Lane is shown on sheet 4 of the RoWA plans. There are three rights of way affected:

a) Slough 49 which crosses over the M4 on the existing Oldway Lane overbridge. This right of way will be closed and substituted by a new right of way on the replacement overbridge. The replacement bridge will have 1.8m high parapets making it suitable for use by pedestrians, cyclists and equestrians,

b) Slough 9 which runs along the south side of the M4, west of Oldway Lane. The replacement Oldway Lane overbridge will be approximately 1.1m higher than the existing bridge and so the approach embankments will need to be increased in height. The length of this right of way which climbs up the western side of the south embankment will be closed and substituted by a new right of way connecting to the new Slough 49 right of way.

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c) Slough 14/5 which runs along the north side of the M4, east of Oldway Lane and south of Chippenham. As with Slough 9 the length of this right of way which climbs the bridge embankments will be closed and substituted by a new right of way.

4.9.3 Oldway Lane and Old Slade Lane overbridges are proposed as online replacements. Highways England proposals include sufficient arrangements for future use of the rights of way affected by the works. Details of the affected rights of way are shown on sheets 4 and 9 of the RoWA plans with further detail included in Schedules 3 and 4 of the draft DCO.

4.9.4 Old Slade Lane is shown on sheet 9 of the RoWA plans. There are four rights of way affected:

d) Colnbrook with Poyle 2 (Old Slade Lane) which crosses over the M4 on the existing Old Slade Lane overbridge. This right of way will be closed and substituted by a new right of way on the replacement overbridge. The replacement bridge will have 1.8m high parapets making it suitable for use by pedestrians, cyclists and equestrians. There is also a private means of access over the bridge which will also be stopped up and a replacement access provided over the new bridge,

e) IVE 20/3 which runs along the north side of the M4, west of Old Slade Lane. No alteration is proposed for this right of way. However, temporary closure will be required during the reconstruction of the overbridge.

f) IVE 31/2 which runs along the north side of the M4, east of Old Slade Lane. No alteration is proposed for this right of way. However, temporary closure will be required during the reconstruction of the overbridge.

g) Colnbrook with Poyle 6 which heads south from Old Slade Lane towards Lakeside road and Colnbrook Bypass. This right of way will be kept open throughout construction to maintain access to Old Slade Lake.

4.10 Although Riding Court overbridge is located outside the Borough, drivers use it to gain access to the A4 and A332 within Slough. SBC considers that consideration should be given to the relocation of the overbridge north- west of its present position to provide better access to the future CEMEX Riding Court Farm sand and gravel extraction site.

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Highways England's Comment

4.10.1 This suggestion by SBC describes Highways England’s proposal for the replacement of Riding Court overbridge, i.e to provide an offline replacement structure to the north-west side of the existing bridge. This will enable access across the M4 to be maintained throughout the construction period.

Underbridges

4.11 SBC notes the proposed widening of the Windsor Branch Rail bridge on the southern side and has no adverse comments on the design at this stage subject to the outcome of HE’s review into embankment options (7.7.23 APP-096).

4.12 The proposed works to the two road underbridges at Langley Interchange offer the opportunity for modifying the roundabout to provide bus priorities: this is discussed in Section 8.

Highways England's Comment

4.12.1 The review into the embankment widening options is still in progress but Highways England can confirm that the detail design solution will be constrained to fit within the existing motorway boundary and that land required for the construction will be acquired on a temporary basis only. The boundaries and extent of temporary land required are shown on sheet 22 of the Land Plans (Application Document Reference 2-2).

4.12.2 The proposed works to the two road underbridges is addressed by Highways England in response to section 8 below.

5. IMPACT ON ROAD USERS

Traffic Safety and Information

5.1 Given the relatively limited distances between Junctions 5, 6 and 7 and the amount of M4 traffic, especially at peak times, SBC is concerned that the All Lane Running(ALR) proposed in the Scheme would give rise to safety issues and will be interested in the responses from HE to the ExA’s questions on this subject. Incidents on the Slough section of the M4 are unfortunately quite common and collisions can have a major impact, not only to those personally involved but to other road users through delays and congestion.

Highways England's Comment

5.1.1 Highways England answered the ExA's question on safety in Section 6 of Highways England's Response to First Written Questions. The responses give should provide comfort to SBC that Highways England has considered the

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safety issues arising from ALR, and considers that the safety implications from ALR will be no worse than the baseline. This is confirmed in the Hazard Log report, Annex E of the Engineering and Design Report, (Application Document Reference 7-3), outlines the hazard analysis work undertaken and leads to the conclusion that, the All Lane Running design of the M4 J3-12 Scheme is likely to be no worse in terms of safety performance (than the baseline).

5.1.2 The Scheme will deliver the additional capacity required without compromising overall safety. The hazard assessment methodology used to assess the expected safety performance of the smart motorways concept uses evidence (i.e. monitoring data based on performance) built up from the M42 Pilot and more recent operational smart motorway schemes, (e.g. hard shoulder running schemes on the M6 around Birmingham and M62 J25-30). This has demonstrated that the use of the hard shoulder, as an additional lane, does not compromise overall safety.

5.1.3 With regard to incidents on the Slough section, the collision rates (both accidents per 100m veh-km and accidents per mile) around the Slough area (junctions 5 to 7) are no worse than the collision rates on junction 3 to 12 scheme between 2009 and 2012. Further, the rate of ‘serious’ severity collisions (1.00 accidents per 100m veh-km and 0.48 accidents per mile) are marginally better on this section than that of the entire M4 junctions 3 to 12 (1.26 accidents per 100m veh-km and 0.55 accidents per mile). These figures are based on data from DfT published STATS19 for collisions between 1 October 2009 and September 2012 (ref: https://data.gov.uk/dataset/road- accidents-safety-data).

5.1.4 In regard to collision delays and congestion, the Hazard Log for the scheme takes into account the numbers of accidents that occur on the Slough section and throughout the full scheme. Annex E concludes that the Scheme can expect “A reduction in risk for 13 of the 17 highest scoring existing motorway hazards (i.e. those with a risk score of E08/S08 and above), due to a controlled environment being provided through a combination of regularly spaced [variable] mandatory speed signals, speed enforcement, and full CCTV coverage.”

5.1.5 On that basis, it is not expected that there would be any increase in significant delays in the event that an accident occurs along the Scheme. As outlined within the Engineering and Design Report (Application Document Reference 7-3), improvement of the M4 to a smart motorway will help to relieve

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congestion by permanently converting the hard shoulder to a running lane and using technology to vary speed limits and manage traffic. It is expected that the frequency of breakdowns in live lanes will be substantially less than the existing frequency of breakdowns on the hard shoulder, as a significant proportion of breakdowns will be able come to a halt in an emergency refuge area ("ERA"). Discretionary (illegal stops) will be significantly reduced as road users are more likely to only stop in an emergency. The M42 Pilot found breakdowns approximately halved as detailed in 9.4.4 of the Engineering and Design Report. Although the risk of live lane stoppages may increase, Highways England has standard control measures to mitigate against this risk e.g. implementation of a controlled environment through Variable Mandatory Speed Limits and Closed Circuit Television (CCTV). Highways England can also protect the area through the setting of signs and signals and the use of the full CCTV coverage to manage efficient responses to incidents. Consequently, most of the current motorway risks are expected to reduce as a result of the implementation of all lane running (see paragraph 10.3.6 of the Engineering and Design Report) more than compensating for any increase in risk for stopping in a live lane.

5.2 SBC submitted comments on the HE’s variable speed management consultation and sought confirmation that the introduction of this regime would result in better incident management and reduce the need to divert M4 traffic onto the local road network. Other points raised by SBC were:

(a) Need for widespread publicity in advance of speed management being introduced to raise awareness and give drivers early warning;

(b) Interaction between variable speed working on the M4 and that on the M25 and M3;

(c) Interaction between Advanced Motorway Indicators/ Variable Message Signs between Junctions 4B and Junction 8/9, i.e. to what extent will speeds be varied between the junctions used by traffic entering/ leaving the M4 at Slough; and

(d) Further consultation requested on information to be displayed on direction signs, e.g. directing HGVs to Slough Trading Estate.

Highways England's Comment

5.2.2 The introduction of the Scheme will result in better incident management. The extra controls provided through smart motorway features will be able to support the identification of vehicles in the live lane through the queue protection system during peak times. The use of full CCTV coverage to find

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vehicles will allow quicker identification of vehicles in a live lane and allow emergency resources to be dispatched in a timely manner. The management of an incident including access by emergency vehicles is outlined in paragraph 9.4.5 of the Engineering and Design Report (Application Document Reference 7-3).

5.2.3 As is currently the case on smart motorways, Highways England will be able to create an emergency lane(s) (any lane on the motorway) by managing traffic with signs and signals to provide access for the emergency services or traffic officers. Signs and signals will set a lane 1 or lane 4 closure to create an incident access lane for emergency services. If it were not possible to reach the incident in the same direction of traffic, safe operating procedures will be in place so that access can be provided from the opposite direction if necessary.

5.2.4 For road users, speed limits and lane availability will be indicated through the use of variable message signs (VMS) using lane divert arrow signals (to divert traffic) and Red ‘X’ signals (for lane closures). This is stated in paragraph 10.3.16 of the Engineering and Design Report.

5.2.5 With regard to the need to divert traffic onto the local road network, there would only be a need to do this in the event of a significant incident, however, the Scheme expects to see a reduction in the level of risk. In general terms, although additional capacity is created on the mainline, the traffic modelling shows that the Scheme will result in a reduction in congestion on the M4 in both opening year and 15 years later (see paragraphs 4.3.3 and 4.3.4 of the Engineering and Design Report, Application Document Reference 7-3). At the same time, the Scheme will have a net positive impact on traffic flows on the surrounding road network.

5.2.6 The local roads potentially affected by the Scheme were identified and assessed in the Environmental Statement, Chapter 13, Effects on All Travellers (Application Document Reference 6-1). In particular, Tables 13.4 and 13.5 identify local roads in the vicinity of Junctions 10 and 11 of the M4. The results of the assessment on these roads is set out in Tables 13.27 to 13.29 and summarised in paragraphs 13.8.6 to 13.8.9, which conclude overall that the impact is neutral.

5.2.7 With regard to point (a) above, Highways England seeks to provide information on incidents/congestion further along the network, on the basis this may enable drivers to choose an alternative route if they are made aware of circumstances sufficiently in advance. The equipment installed as part of each

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smart motorway scheme provides a highly controlled environment which allows better detection and management of incidents. During busy periods, radar devices or detection loops below the road surface are used to identify breakdowns in traffic flow and automatically set lower speed limits on the approach to an incident or congestion. The overhead electronic signals can also be used to display warning messages to approaching drivers and close lanes to protect vehicles. Signs display messages as part of a strategy to help promote various initiatives; however, these would always be overridden by other messages.

5.2.8 With regards to point (b) above, the speed limits on the Scheme will be automatically set in response to the road conditions. Should congestion begin to build then the signalling system will react accordingly and automatically set reduced speed limits to manage the flow of traffic. Should there be an incident on Scheme, the Operator at the Regional Control Centre (RCC) is able to set appropriate signs and signals if necessary. Depending on the location (i.e. should the incident occur near the M25 merge or diverge) then it may be necessary for appropriate signs and signals to be set on the M25. The signalling rules will automatically set signals upstream (whether that be on the M4 or M25) once the Operator has set a signal at a specific location to protect the scene at an incident.

5.2.9 With regards to point (c) above, the speed limits on the Scheme will be automatically set in response to the road conditions. Depending on the level of congestion, the automatically displayed speed limits will display 40mph, 50mph, 60mph or the national speed limit. The system is programmed not to vary the speed unnecessarily – the system will moderate traffic speeds in order to improve and smooth the flow of traffic through the section.

5.2.10 With regards to point (d) above, the Advanced Direction Signs (ADS) have been consulted upon through the consultation period for the Application. None of the signs relate to specifically directing HGV drivers to the Sough Trading Estate. Further discussions can be undertaken through the Detailed Design stage should there be a need for further information to be included on signs.

5.3 As well as requesting further discussion about direction signing SBC sees the opportunity for more collaboration between HE and the local highway authorities on wider driver information. SBC has a strategy for deployment of ITS in the Borough and would welcome an exploration of how this could be linked with HE’s ITS proposals for implementing variable speed limits, lane control and variable message signs.

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Highways England's Comment

5.3.1 Highways England welcomes the opportunity to have further discussions and collaboration with SBC on how the deployment for ITS in the Borough could be linked to Highways England’s proposals for the implementation of smart motorways.

5.4 In carrying out its Network management duty SBC is required to facilitate ‘the expeditious movement of traffic on road networks for which another authority is the traffic authority’. Both SBC and HE therefore have a responsibility to work with each other to achieve this goal including coordination meetings, providing information about planned works and developments, and contacting each other in emergency situations. This includes the potential for the sharing of information for use within the ITS equipment operated by the respective partners. SBC has recently installed a number of state of the art VMS at strategic locations and sharing and displaying information relating to cross-authority traffic movements would have a positive impact for drivers travelling into, through and out of Slough as follows:

(a) Northbound on A355 Tuns Lane between the M4 Junction 6 roundabout and the Copthorne roundabout. (Useful information for drivers leaving the M4 and approaching Slough Trading Estate or the town centre);

(b) Westbound on A4 Bath Road towards the Huntercombe Spur roundabout. (Useful information for drivers heading out of Slough on traffic conditions around Junction 7 of the M4); and

(c) Eastbound on A4 Bath Road, approaching the Huntercombe Spur roundabout. (Useful information for drivers approaching a decision point, either to continue on the A4 or to turn onto the Huntercombe Spur link towards Junction 7 of the M4.

Highways England's Comment

5.4.2 Highways England welcomes the opportunity to work more closely with SBC in order to share knowledge and information and also to discuss planned works and development and emergency situations. With the ITS introduced by SBC and by Highways England there are significant opportunities to work together and look at how both organisations can help each other to provide accurate and reliable information to the road user. This would enable road users to make informed decisions on their journey prior to reaching either the SBC local road network or prior to reaching the Highways England network.

5.5 This is all subject to having the ability for data / information to be transferred between systems. Such transfer would have to be automated to be most effective; however some manual intervention would inevitably be required. SBC is therefore very keen to enhance the network management partnership arrangements with HE. Any positive impact on the local area will be maximised by increased

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commitment from both parties, for example commitments to develop interfaces between the HE and SBC ITS systems and to share data and information to facilitate the development of an ITS strategy and incident management or contingency protocol alongside HE’s operational schedule.

Highways England's Comment

5.5.1 Highways England agree that automated systems would provide the greatest benefit to enable road users to be provided with appropriate information. Highways England are prepared to consider the sharing of data and information as part of their partnering with local highway authorities. Discussions between Highways England and SBC can be progressed through the development of the Scheme.

5.6 SBC understand that enforcement of variable mandatory speed limits is planned to be carried out using a combination of gantry-mounted and verge mounted speed enforcement equipment, and traditional enforcement by the Police. As the distances between Junction 5, 6 and 7 are relatively short, SBC considers that average speed enforcement would prove a more effective alternative.

Highways England's Comment

5.6.1 At present, all smart motorway schemes are to be enforced by speed enforcement cameras which can be located on a gantry or on verge mounted MS4s. The cameras will provide spot speed enforcement. There is currently no approved average speed enforcement system which would enable the enforcement of variable speed limits on smart motorway schemes. However, levels of compliance will be monitored for the early smart motorway schemes. Should there be any issues with non-compliance on these schemes then additional measures to enforce speed limits may need to be considered for the Scheme in this respect.

Traffic on Local Roads

Operational Scheme

5.7 As outlined in Section 1 there is a close relationship between traffic movements on the M4 and the local road network, emphasised by the presence of 3 junctions along a relatively short motorway section at Slough. Current experience is that motorway incidents and events lead to congestion which encourages drivers to divert onto local roads through Slough. The aim of the Scheme is to reduce congestion, smooth the flow of traffic to improve journey times and make journeys more reliable. SBC remains unconvinced that this aim can be achieved without some knock-on effect on local roads, taking into account the forecast increase in M4 traffic. Some of this increase, at least, is likely to be generated by traffic accessing the motorway at Junction 5, 6 or 7 – all involving use of the A4 and/ or A355. SBC

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is not aware that a quantitative assessment has been made by HE of the impact of the Scheme on local roads, i.e. consideration of the net effect of indirectly encouraging car use which could present additional local car journeys as residents enter/exit the M4. Another issue is the impact on non- motorised road users as a result of this effect and also during diversions in the case of an incident.

Highways England's Comment

5.7.1 Highways England agrees that junctions 5, 6 and 7 form important links with the local road network that serves Slough, including its extensive Trading Estate. It is also acknowledged that these local roads combined with accessibility from three junctions in close proximity offer opportunities for drivers to divert from the M4 in the event of major incidents. However, Highways England does not agree that the Scheme will generate significant numbers of additional car journeys. The following paragraphs provide details of the checks made on this issue from the outputs of the variable demand transport model used to develop the traffic forecasts for the Scheme.

5.7.2 Table A-5 within Appendix A of the Traffic Forecasting Report provides details of the total amount of trips forecast in the Do Minimum (without Scheme) and Do Something (with Scheme) highway matrices for each of the modelled time periods for the opening (2022) and design (2037) years split by light and heavy vehicles. The difference between the two sets of matrices represents the amount of ‘induced’ traffic arising from the implementation of the Scheme.

5.7.3 As shown in Table A-5 the overall levels of induced trips, relative to the Do- Minimum scenario, are less than 0.3 % in all time periods in both forecast years. Over a 12 hour day, the level of induced traffic would equate to some 6500 additional trips out of a total of 465,000 or 0.14%.

5.7.4 In addition, Tables A-31 and A-32 show that there is negligible switch from public transport to highway trips and Tables A-33 and A-34 show there is also negligible change in the time of day that trips take place.

5.7.5 Based on the above, it is concluded that there is only a small amount of induced traffic, and that there is negligible change in mode or time of day that trips take place. Accordingly the majority of “additional” traffic forecast to use the Scheme is already on the highway network and is re-assigned from existing, less suitable roads. Therefore, Highways England considers that the Scheme will not encourage additional local car journeys that would enter/exit the M4 at Junctions 5, 6, or 7.

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5.7.6 During major incidents when the M4 is closed, Highways England accepts that traffic is likely to increase on alternate routes. However, the provision of the Scheme offers the ability to maintain additional capacity during incidents and to control traffic on the approach to incidents. This will allow smoother flows, which should reduce the incentive for traffic to divert onto the local highway network, impacting on the amenity of local road users and non-motorised users alike. Should there be a need to strategically divert traffic due to an incident on the M4, the signs and signals on other parts of the Highways England network will be able to provide appropriate information to motorists so that they are made aware of the incident and can therefore change/re-route their journey as necessary in order to reach their destination.

5.8 In APP-153 HE make however a qualitative assessment of ‘driver stress’ on local roads that feed in to the M4. Table 13.8 suggests that stress is currently ‘high’ on:

(a) Junction 7 M4 Huntercombe Spur northbound;

(b) Junction 6 A355 Tuns Lane northbound; and

(c) Junction 5 A4 London Road/Colnbrook Bypass west and eastbound to/from Heathrow.

5.9 Table 13.27 foresees no change in stress by 2037 on these roads with or without the Scheme. Stress levels on the A355 Tuns Lane southbound to Junction 6 are shown to go up from ‘low’ to ‘moderate’. On the A4 London Road between Junction 5 and Slough town centre stress levels are expected to remain ‘moderate’.

5.10 In December 2015 SBC are planning to begin implementation of the ‘A355 Route Enhancement scheme’ aimed at reducing congestion and improving safety along A355 Tuns Lane between Junction 6 and the A4 in Slough and the main access to Slough Trading Estate. This scheme has the support of the Thames Valley Berkshire Local Enterprise Partnership and features in the Strategic Economic Plan for Thames Valley Berkshire. Most of the funding for the scheme is being provided from the Local Growth Fund. The A355 scheme includes the remodelling of the Copthorne roundabout (located between Junction 6 and the A4 Bath Road), signal and junction upgrades and selected widening.

5.11 Between the Copthorne roundabout and Junction 6 SBC will be implementing a 30mph speed limit. The traffic signals at the motorway junction are currently operated by Reading Borough Council and maintained by SBC. Microprocessor Optimised Vehicle Actuation (‘MOVA’) is being installed and SBC is seeking to take over the operation of the system. It is understood that HE will continue ramp metering for both east and westbound traffic. Through coordination with HE SBC is seeking to ensure the smooth running of traffic between Junction 6 and the A355 in Slough, particularly for ‘high stress’ northbound movements.

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Highways England's Comment

5.11.1 Ramp Metering is proposed to be retained at junction 5 and junction 6 westbound and junction 6 and junction 7 eastbound (section 9.5 of the Engineering and Design Report – Application Document Reference 7-3). As per the requirements of relevant standards (IAN 161/13 and IAN 103/08), these sites were assessed to determine if they will continue to provide benefit following implementation of the Scheme. The sites were assessed as passing the operational criteria. With Through Junction Running being introduced at these junctions, the likelihood is high that they will continue to pass the operational criteria. The sites will be recalibrated so that they take any changes in operation (i.e. the 30mph limit between junction 6 and the A355) into account. Highways England will continue to work closely with SBC to manage traffic most effectively in the vicinity of junction 6.

5.12 The traffic signals at Junction 5 are also currently operated by Reading Borough Council and maintained by SBC. As with Junction 6, SBC sees it essential as local highway authority to have the means to manage traffic flows at this important roundabout and coordinate with ramp metering by HE which it is understood will continue for westbound M4 traffic. East of this roundabout the ‘high stress’ A4 London Road/ Colnbrook Bypass is an important connection to Heathrow Airport, representing the strategic interface between the M4 and the local road network. (The A4 is also the route of the SMaRT bus rapid transit scheme- see 8.4, 8.5.

Highways England's Comment

5.12.1 Highways England has addressed ramp metering in the response to the representation above and notes the importance of the junction 5 roundabout as well as the connection to Heathrow Airport. Highways England agrees that the strategic interface between the M4 and the local road network needs to operate effectively in order to best manage traffic in the SBC area. Highways England will continue to work closely with SBC to manage traffic most effectively in the vicinity of junction 5.

Construction Phase

5.13 SBC notes that the construction phase on the M4 ‘main line’ will involve narrowing lanes and a 50 mph speed limit: this may encourage some drivers to divert from the motorway on to the local road network. SBC would seek cooperation from HE to discourage this. Shuttle working is proposed for the M4 Huntercombe Spur overbridge and slip road works and SBC is concerned about the potential impact on traffic movements at its intersection with A4 Bath Road. This is especially the case if the

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shuttle working were to continue throughout the duration of the reconstruction works which it is understood could last for 26 months.

Highways England's Comment

5.13.1 Paragraphs 8.3.1 – 6 of the Engineering and Design Report (Application Document Reference 7-3) describe the proposed traffic management regime and phasing of the works during the construction of the Scheme. To provide a more complete assessment than the driver stress assessment of the possible effect of the construction traffic management on users of the M4, the Highways England bespoke software program QUADRO (QUeues And Delays at ROadworks) was run. Analysis of the delays predicted by the program shows that the delays arising from the additional time to travel through the works during the first phase of works reached a maximum predicted journey time extension of 10 minutes in each of the Monday – Thursday peak periods. Only during the Friday PM peak in the westbound direction do journey extensions exceed 10 minutes and queues occur.

5.13.2 During phase 2 of the works, the capacity is exceeded during peak periods between junctions 3 and 4 and between junctions 5 and 6. The potential level of diversion as assessed by QUADRO is limited in number, totalling 106 vehicles per day, two-way Monday to Thursday between junctions 3 and 4 and a total of 296 vehicles per day, two-way Monday to Thursday between junctions 5 and 6.

5.13.3 The conclusion of the QUADRO assessments, that a limited amount of traffic diversion will occur during the construction of the Scheme, is also reinforced by a comparison of traffic flow data during roadworks on the M4 during 2014. Two sets of works were undertaken – resurfacing between junctions 8/9 and 10 and bridge works between junctions 10 and 11, each using 3 narrow lanes of traffic management. Comparisons were made between traffic flows during these works and the previous year using data from Highways England’s Traffic Data System (TRADS) database. The comparisons showed that flows in 2014 were lower than the preceding year only during the peak periods, which suggests that any diversion was limited to those time periods.

5.13.4 The proposed shuttle working for the works at Huntercombe spur overbridge will be carefully managed and employ vehicle actuation to maintain queue lengths within the available storage space and avoid blocking back through the A4 junction.

5.14 The duration of the Huntercombe Spur works and planned dates for start and completion are however unclear and SBC has identified a number of differences between the programme put forward for bridge and other works in the Outline Construction Programme (APP-107) and the details set out in other

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documents (e.g. APP-153). It is acknowledged that detailed programming would be continually refined but greater clarity is essential at this stage so that the likely impact on the local road network can be assessed, bearing in mind the other major infrastructure schemes planned for the Slough area- see 8.1, 8.2.

Highways England's Comment

5.14.1 The duration of Huntercombe Spur bridge works is to be reviewed on completion of the detailed design. The current programme is based upon the construction of the two new bridges sequentially with partial demolition of the existing bridge being undertaken in halves prior to constructing each bridge. The works to the Huntercombe spur site will be accessed from the motorway network and thus not impact the local network.

5.14.2 Two-way vehicular access over the existing bridge will be maintained throughout the duration of the construction works, apart from specific short duration night time closures for specific operations. The junction will remain operational at all times apart from short duration night time closures.

5.14.3 A detailed Construction Traffic Management Plan (“CTMP”) will be developed in consultation with the local authorities and stakeholders during the construction planning phase to ensure impact to the local highway network is minimised, and to ensure coordination with the construction of any other infrastructure development in the Slough area. The CTMP will form part of the Construction Environmental Management Plan and will therefore be secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

5.15 The proposed shuttle working during construction of the new Datchet Road overbridge (potentially lasting 20 months) has the potential to create significant journey delays on the B376 which links Slough to Datchet, Old Windsor and Staines.

Highways England's Comment

5.15.1 Highways England disagrees that the proposed shuttle working during construction of the new Datchet Road overbridge will create significant journey delays on the B376.

5.15.2 Shuttle working would only be used for works to tie-in the existing Datchet Road to the new bridge and for any local works where the new bridge works overlap with the existing such as for the construction of the new bridge north and possibly south abutments. These periods will be for a duration of

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approximately 2 months rather than for the full construction period, which Highways England agrees will be 20 months.

5.16 At the Langley Interchange reference is made in Table 13.20 of APP-153 to the narrowing of lanes on the M4 ‘main line’ during widening of the underbridges and the outline programme (APP-107) suggests that these works could last for 12 months. SBC is unclear how these works would affect traffic movements on the Junction 5 roundabout and is concerned about potential increases in congestion and journey delays on the A4 and B470 that could arise from traffic management proposals.

Highways England's Comment

5.16.1 Narrowing of the lanes on the M4 is required to provide working space at M4 level to widen the Langley Interchange overbridges. Narrow lanes would also be required to provide working space at roundabout level during the early stages of the bridge widening. Traffic management will be provided to maintain the traffic routes and number of lanes through the works and on the roundabout. A Construction Traffic Management Plan ("CTMP") will be developed for the Scheme. This will be prepared following consultation with the stakeholders to understand all the issues, to ensure that the traffic management plan addresses all relevant concerns. The CTMP will form part of the Construction Environmental Management Plan and will therefore be secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

5.17 HE foresee construction of the Scheme giving rise to some 150,000 two way HGV movements, averaging 150 vehicles per day over the estimated 1000 working days of the project. Without some indication of the routes that would be needed for HGV movements it is difficult to judge the likely impact on the local road network. SBC acknowledges that this would partly depend on the location of Construction Compounds, the use to which they would be put (including the siting of the main office) and the duration of their operation. It is understood that these issues would be left to the future contractor to address: this is unhelpful particularly in the light of other major schemes in the area which are due to generate significant HGV flows- see Section 8.

Highways England's Comment

5.17.1 A Construction Traffic Management Plan ("CTMP") will be developed for the Scheme. This will be prepared following consultation with the stakeholders to understand all the issues, to ensure that the traffic management plan addresses all relevant concerns. The CTMP will form part of the Construction Environmental Management Plan and will therefore be secured by

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Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

5.18 Proposed Construction Compound No. 9 is located within the Borough and SBC notes that the DCO boundary extends along Sutton Lane: the reason for this is not clear. HGV movements along Sutton Lane and the A4 London Road/ Colnbrook Bypass are already significant and have an adverse impact on the amenities of local residents including air quality (the Brands Hill Air Quality Management Area). SBC is concerned that HGV flows to and from a compound in this location would exacerbate existing traffic and safety problems in this general area.

Highways England's Comment

5.18.1 The DCO redline boundary extends along Sutton Lane because plots 25-30 and 25-31 are required as “Temporary land required for use as construction compound”.

5.18.2 A Construction Traffic Management Plan ("CTMP") will be developed for the Scheme. This will be prepared following consultation with the stakeholders to understand all the issues, to ensure that the traffic management plan addresses all relevant concerns. The CTMP will form part of the Construction Environmental Management Plan and will therefore be secured by Requirement 8, Schedule 2 of the Draft DCO (Application Document Reference 3-1).

5.19 SBC notes the Outline CEMP (APP-293) and draft DCO Requirement 8 relating to a CEMP being submitted for approval to the relevant Local Planning Authority, including a plan for managing traffic. Management of traffic across the local road network would be a challenge, given that most journeys cross administrative boundaries, and SBC is unclear how the CEMP regime would be applied. SBC agrees with the ExA’s questioning the wording of Requirement 8 which would currently allow HE to modify the CEMP once the Scheme had started without seeking the agreement of the Local Planning Authorities and also would offer no commitment to delivery of mitigation measures.

Highways England's Comment

5.19.1 Whilst many journeys will cross administrative boundaries, traffic management measures themselves will either be on the M4 itself or in areas local to work sites and hence most likely falling within one administrative area or another. Where traffic management may have some impact on a wider area, this will be treated on a case by case basis with the administrative area(s) concerned.

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5.19.2 Highways England has agreed to the deletion of sub-paragraph 3 in requirement 8. This amendment is reflected in the revised draft of the DCO which was submitted at Deadline II.

Non-motorised forms of travel

5.20 The Scheme would have an impact on public rights of way in the Borough as a result of closures and diversions. During the construction phase the disturbance to a number of rights of way could extend for lengthy periods. Surveys of non-motorise users have been carried out by HE where public rights of way cross the M4 by overbridges that would be reconstructed on-line. SBC consider that the survey should have been extended to Wood Lane and the Windsor Brach Rail bridges where users could be disadvantaged the works even though they are off-line.

Highways England's Comment

5.20.1 Highways England confirms SBC’s understanding that the focus of the NMU surveys was to understand the level of usage of those bridges to be reconstructed on line.

5.20.2 Existing Public Rights of Way (“PRoW”) are identified on the Environmental Masterplan (shown on sheets 1 to 31 of Annex A1 to the Engineering and Design Report (Application Document Reference 7-3)). Paragraph 5.2.176 of the Planning Statement (Application Document Reference 7-1) confirms that no PRoW are to be extinguished permanently as a result of the Scheme, although a number will experience temporary closures during construction works.

5.20.3 Surveys of non-motorised users have been carried out by Highways England where PRoW cross the M4 by overbridges that will be reconstructed on-line, for example Recreation Ground overbridge and Old Slade Lane overbridge, where disruption to non-motorised users as a result of severance has been assessed as severe in paragraphs 13.7.20 and 13.7.21 of the ES (Application Document Reference 6-1). The use of Wood Lane by pedestrians, equestrians and cyclists is only likely to experience temporary short-term disruption as a result of construction works and as such, severance issues have not been deemed significant. Similarly, users of cycling and walking routes along either side of the Windsor Branch Railway Bridge may experience adverse impacts at certain times during the underbridge widening works; although diversion routes during these periods of closure may range from moderate to severe (depending for example on direction of travel), routes will remain open to users at most times and consequently any impact will only be for a short duration (paragraph 13.7.28 of the ES (Application Document Reference 6-1)).

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5.21 SBC’s understanding of the effect of individual bridge works is as follows:

(a) Oldway: closure of bridleway SLO 49 and diversion for approx 8 months;

(b) Wood Lane: bridleway SLO 17would transfer to the new bridge when completed (approx 20 month period);

(c) Windsor Branch Rail: footpaths SLO 32 and 33a (part of Slough- Windsor cycle route) run on either side of the railway and would be subject to temporary closures;

(d) Recreation Ground (just outside Borough boundary): closure of right of way (including NCN 61) and diversion for approx 8 months;

(e) Langley Interchange: closure of subway (footpath SLO 9) and diversion for approx 12 months; and

(f) Old Slade: closure of footpath Colnbrook with Poyle 24 (Colne Valley Trail) and diversion for approx 12 months.

Highways England's Comment

5.21.2 Highways England confirms that the SBC's understanding of the effect of individual bridge closures is broadly correct, with the exception of:

(a) Oldway Lane – temporary closure and diversion of bridleway SLO49 may be necessary for a slightly lengthier period than suggested here (up to ten months) (paragraph 13.7.19 of the ES (Application Document Reference 6-1);

(b) Wood Lane – it is proposed that the Wood Lane overbridge be reconstructed offline and as such the existing bridge will remain open both to traffic and to non- motorised users during the construction period with short periods of closure when the new bridge is tied into existing approaches (paragraph 13.7.25 of the ES (Application Document Reference 6-1). The twenty months period referred to above does not therefore relate to a closure period for bridleway SLO17 but for offline bridge construction works; and

(c) Windsor Branch Railway Bridge – as described in Highways England’s response to paragraph 5.20, users of cycling and walking routes along either side of the Windsor Branch Railway Bridge may experience adverse impacts at certain times during the underbridge widening works; although diversion routes during these periods of closure may range from moderate to severe (depending for example on direction of travel), routes will remain open to users at most times and consequently any impact

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will only be for a short duration (paragraph 13.7.28 of the ES (Application Document Reference 6-1)).

5.22 The closure of the Oldway, Recreation Ground and Old Slade overbridges for on-line replacements would involve inconvenient diversions for users over lengthy periods. Potential diversionary routes are outlined by HE and it is proposed that the details be left to be resolved by the CEMP under draft DCO Requirement No. 8. SBC considers that leaving all details to that later stage would be unreasonable and put users at a disadvantage. As found by the HE user survey these rights of way are of value to local communities with some, like the Langley Interchange subway and Recreation Ground overbridge, very well used with significant numbers of children, school pupils and cyclists as well as adult pedestrians.

Highways England's Comment

5.22.1 Highways England acknowledges that the closure of the Oldway Lane, Recreation Ground and Old Slade Lane overbridges for on-line replacements will involve the temporary severance of rights of way during construction works, with an associated need to identify alternative routes for non-motorised users.

5.22.2 In order to ensure that users of routes will not be put at a disadvantage by the use of diversions, paragraph 4.1.1 of the Outline Construction Environment Management Plan (“CEMP”) (Appendix 4.2A of the ES) (Application Document Reference 6-3) notes that a community engagement strategy will be produced by Highways England. The strategy will include procedures to not only maintain effective community engagement throughout the construction period, but also to inform affected communities in advance of relevant construction works, including the programming thereof. Paragraph 4.2.1 of the Outline CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3) states that methods identified to communicate matters during construction works include on-line communication, a Scheme newsletter and notification to local residents, businesses and key stakeholders as appropriate, of planned construction works a minimum of two weeks in advance. As noted in the representation, the CEMP is secured by Requirement 8, Schedule 2 of the draft DCO.

5.23 SBC takes the view that changes to the use of rights of ways that would be caused by the Scheme should be considered in a more comprehensive way. Improvement works for example are likely to be needed to diversionary routes, the cost of which should not have to be borne by the local authority. Such improvements would supplement those already being sought by the local authorities in relation to

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the new overbridges at Old Slade (designation as a bridleway) and Recreation Ground (NCN 61 cyclepath enhancements).

Highways England's Comment

5.23.1 Highways England has assessed the effect of the Scheme on NMUs in the ES in chapter 13. It has not concluded that any of the diversions proposed is in any way subject to a need for improvement as a result of the Scheme and the temporary use of the diversionary route. Furthermore, the Council has not identified the need for any particular improvement. As such, it cannot be concluded that there is a need for further works.

5.24 Four other issues need to be raised:

(a) Wood Lane: HE propose to maintain access for bridleway and footpath users during construction of the new overbridge: details of these arrangements are needed;

(b) Datchet Road overbridge: arrangements need to be clarified for maintaining access for pedestrians and cyclists across the M4 in the transition from the closure of existing bridge and opening of the new;

(c) Langley Interchange pedestrian subway: HE propose to provide a temporary route for pedestrians and cyclists around the Junction 5 roundabout; this needs to be considered as part of the comprehensive investigations called for in 8.5; and

(d) Proposed site for Compound No. 9: development of this site would seriously affect Public Footpath Slough 8 which crosses it diagonally.

Highways England's Comment

5.24.2 The Outline Construction Environment Management Plan (“CEMP”) (Appendix 4.2A of the ES) (Application Document Reference 6-3) states in paragraph 13.2.1 that the contractor will implement traffic management measures during the construction of the Scheme on all public roads and non- motorised paths. A detailed Construction Traffic Management Plan ("CTMP") will be required for the construction period to ensure the safe transition for road users from existing roads to traffic managed sections. Paragraph 13.2.5 of the Outline CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3) states that the final CTMP will include details of existing pedestrian, equestrian and cyclist routes; measures to provide for the safety of traffic, the public and construction staff during traffic management works. Paragraph 13.7.3 of the Outline CEMP (Appendix 4.2A of the ES) (Application

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Document Reference 6-3) states that the final CTMP will be required to include information relating to traffic management layouts, signing and apparatus to be implemented on all affected NMU rotes. Furthermore, paragraph 12.7.2 of the Outline Construction Environmental Management Plan (CEMP) states that “…..Diversion works will require to be confirmed in consultation with the relevant local authority and consent applied for under s257 of the Town and Country Planning Act 1990.”

5.24.3 Highways England’s comments in relation to the four issues raised are as follows:

(a) Wood Lane – Details for the arrangements for NMUs during construction of Wood Lane overbridges will be confirmed in the detailed design phase;

(b) Datchet Road overbridge – As Datchet Road overbridge will be constructed off line, the new bridge will be closed for a short diversion while the approaches are tied into the new structure. Temporary diversions will be confirmed for NMUs during the detailed design phase;

(c) Langley Interchange pedestrian subway – Comprehensive planning based upon verification studies will confirm temporary diversion routes during construction. This will be done during the detailed design phase; and

(d) Proposed site for Compound No. 9 – If this site is selected as a construction compound, the contractor will identify suitable footpath diversion routes during the detailed design phase.

6. LAND ACQUISITION

6.1 The Scheme would have an impact on land in statutory allotment use near The Myrke which involves 20 tenanted plots. Statutory allotments close to Huntercombe Spur will also be affected.

Highways England's Comment

6.1.1 Paragraph 5.8.3 of the Socio-Economic Report (Application Document Reference 7-2) states that an area of allotments at The Myrke is likely to be affected as part of the proposed lengthening of the water main subway in this location. Key points to reiterate with regard to the use of the allotment site are: the number of plots included in the assessment represents a worst-case scenario for possible disruption, directly affected plots will be restored to their original condition, and access to unaffected allotments will be maintained during the construction works. Finally, it should be noted that an alternative option which

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does not involve lengthening the structure has been assessed by Highways England and is being actively pursued with Thames Water.

6.1.2 Paragraph 14.9.16 of the ES (Application Document Reference 6-1) notes that an area of allotments at West Point will also be affected by the Scheme, in relation to works required at Huntercombe Spur.

6.1.3 The land within allotment use near The Myrke is in plot 23-35 on the Land Plans (Application Document Reference 2-2). The Statement of Reasons (Application Document Reference 4-1) notes that this plot is required for “Temporary land required for access and working space to extend Water Main subway” for Work number 21.

6.1.4 The land within allotment use close to Huntercombe Spur is in plots 20-25 and 20-26 on the Land Plans. The Statement of Reasons notes that these plots are required for “Temporary land required for access and working space to construct realigned Huntercombe Spur and new Huntercombe Spur overbridge.

6.1.5 As noted at paragraphs 8.1.42 and 8.1.47 of the Statement of Reasons, Highways England considers that the allotments comprised in Plots 20-25, 20- 26 and 23-35 are allotment gardens, and can be subject to powers of compulsory acquisition without coming within section 131 of Planning Act 2008.

6.2 Public open space at Cippenham is located within the Order line and has important boundary trees, embankments, recent tree planting and public rights of way. Other public open space is included within the Order line at Chalvey as is part of the Herschel Local Nature Reserve. Near Recreation Ground bridge is SBC land which forms part of Upton Court Park and is used for motocross purposes.

Highways England's Comment

6.2.1 Public open space at Cippenham is identified in the description of baseline conditions set out in Chapter 4 of the Socio-Economic Report (Application Document Reference 7-2). Paragraph 14.9.6 of the ES (Application Document Reference 6-1) notes that part of the Mercian Recreation Ground is required as part of the temporary land-take for the Scheme. The identification of important boundary trees, embankments and recent tree planting within the public open space at Cippenham is noted. The Outline Construction Environment Management Plan (“CEMP”) (Appendix 4.2A of the ES) (Application Document Reference 6-3) notes that, as part of the final CEMP, the contractor will be required to plan the works in advance to ensure that measures to reduce

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environmental effects are integrated into the construction methods and commitments set out in the ES and DCO, and that those commitments are complied with (paragraph 3.1.5). Paragraph 8.3.2 of the Outline CEMP (Appendix 4.2A of the ES) (Application Document Reference 6-3) notes that at detail design stage, a plan showing areas of existing trees and vegetation to be retained within the Order limits will be prepared, that an arboriculturalist and/or ecological specialist will be required to be involved and that landscape planting plans will be prepared.

6.2.2 Paragraph 4.7.13 of the Socio-Economic Report (Application Document Reference 7-2) notes the presence of Herschel Park located to the north of the M4, with facilities including a nature reserve.

6.2.3 Paragraph 6.8.15 of the Socio-Economic Report (Application Document Reference 7-2) notes the presence of a motocross site located in the immediate vicinity of the Recreation Ground overbridge and that use of the site may be affected by construction works in this location, as may the walking/cycling route north to Upton Park Road.

6.2.4 Public open space has been identified in the borough of Slough in plots 21-02a, 21 -02c, 21-02d, 21-13, 21-15, 21-16, 21-17, 22-12, 22-26 (Cippenham), 23-04 (Herschel Park) and 23-33 (Upton Court Park) on the Land Plans.

6.2.5 The Statement of Reasons notes the following:

6.2.5.1 21-02a is required for “Temporary land required to enable temporary diversion of Rights of Way between Oldway Lane and Wood Lane”.

6.2.5.2 21-02c is required for “Temporary land required to enable temporary diversion of Rights of Way between Oldway Lane and Wood Lane and for access and working space to construct and realign Wood Lane and new Wood Lane overbridge”.

6.2.5.3 21-02d, 21-13, 21-15, 21-16, 21-17 and 21-17 are required for “Temporary land required for access and working space to construct realigned Wood Lane and new Wood Lane overbridge”.

6.2.5.4 22-12 and 22-26 are required for “Temporary land required for access and working space for widening Windsor Branch railway underbridge to the South, including realignment of M4 and J6 Westbound off-slip and embankment strengthening and widening”.

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6.2.5.5 23-04 is required for “Temporary land for access and working space to extend Water Main and Gas Main subway”.

6.2.6 23-33 is required for “Temporary land required for access to finishing works on Recreation Ground road and Recreation Ground overbridge”.

6.3 Part of SBC’s Chalvey local authority depot is included in the Order boundary.

Highways England's Comment

6.3.1 An area of the Chalvey Waste Transfer Station within the ownership of Slough Borough Council is identified as included in the Order boundary (Book of Reference) (Application Document Reference 4-3).

6.3.2 The land within SBC’s Chalvey depot is within plots 22-18 and 22-21 on the land plans. The Statement of Reasons notes their requirement as “Temporary land required for access and working space for widening Windsor Branch railway underbridge to the South, including realignment of M4 and J6 Eastbound on-slip”.

6.4 The arrangements for temporary or permanent use of these parcels of land for the Scheme are still under discussion.

Highways England's Comment

6.4.1 Highways England is in discussion with Slough Borough Council to agree arrangements to acquire land through negotiation, although the requirement for the various plots is not under discussion.

7. SOCIO-ECONOMIC ASPECTS

7.1 SBC is one of the 6 Berkshire authorities on the Thames Valley Berkshire Local Enterprise Partnership which produced the Thames Valley Berkshire Strategic Economic Plan (SEP) submitted to the Government in 2014. The SEP strategy document (see RR-040) states that ‘we welcome the planned M4 Smart Motorway Scheme from Junction 3 out to Junction 12, due to start construction in 2016. This should include screening, noise reduction and air quality measures’. The Scheme also features prominently in the SEP Implementation Plan.

Highways England's Comment

7.1.1 Highways England welcomes the support from the Thames Valley Berkshire Local Enterprise Partnership and notes the aspirations of its Strategic Economic Plan.

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7.1.2 Paragraph 3.3.7 of the Socio-Economic Report (Application Document Reference 7-2) makes reference to the Thames Valley Local Enterprise Partnership and draws specifically on information available in the LEP’s Strategic Plan.

7.2 SBC notes from the Socio-Economic Report (APP-090, para 6.2.7) that it is recognised that ‘Increases in traffic along the route of the Scheme are likely in the future as a result of increasing populations and the continued development of housing and employment areas. Traffic congestion is a possible constraint to the further economic development of the sub-region, affecting not only travel to work journeys, but also the attractiveness of the wider area as a place to live and visit’. SBC agrees that future congestion would have a negative impact on the economy of Slough and Thames Valley Berkshire as a whole and that the Scheme has the potential to provide a more reliable and flexible route for commuters, and indeed for all motorists in the area.

Highways England's Comment

7.2.1 Highways England believes that the Scheme not only has the potential to deliver, but will deliver, improvements in reliability that will be of the benefit to residents and businesses in Slough and the wider region.

7.2.2 Paragraph 6.2.7 of the Socio-Economic Report (Application Document Reference 7-2) goes on to identify that “the operation of the Scheme is anticipated to relieve congestion and smooth the flow of traffic along the M4” and that therefore “it can be expected for there to be improvements in the road network relied upon by local businesses and residents”.

7.3 As outlined in para. 5.7 of this report SBC is concerned however that future increases in traffic along the M4 could generate additional traffic movements on the local road network. SBC notes from the Socio-Economic Report (para 6.2.11) that travel-time data has been used to measure the impact of the Scheme on journey times in the hinterland of the ‘Regeneration Areas’ including Slough. This suggests that journey times in the Slough area within the 30-60 minute category might be reduced by 10% but SBC is uncertain on how this conclusion has been reached: further details would be useful.

Highways England's Comment

7.3.1 Paragraphs 6.2.10 and 6.2.11 of the Socio-Economic Report (Application Document Reference 7-2) refer to findings from the Regeneration Report produced for the Scheme which has identified five Regeneration Areas ("RAs") (one of which is Slough) and used travel-time data both to define the hinterland for each RA and from this to assess the impact on short, medium and long journey travel times. Paragraph 6.2.11 of the Socio-Economic Report (Application Document Reference 7-2) concludes that the largest change in

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travel time occurs in the Slough area, where travel time within the 30-60 minute category for travel to, or from, RAs is reduced by 10%.

7.3.2 Travel time for inbound and outbound commuting was used to define approximately the hinterland for each RA, with an analysis then undertaken for both the ‘do-minimum’ and ‘do-something’ scenarios for a forecast year of 2037. The hinterland area was defined as locations accessible within an average time of an hour.

7.3.3 Forecast assignments from the traffic model were analysed to determine travel time changes for each Regeneration Area to points within the surrounding area (hinterland), up to a maximum of 60 minutes journey time away from the RA. Changes between the ‘do-minimum’ and ‘do-something’ scenario forecasts provide an indicative measure of whether accessibility in the surrounding network improves or worsens.

7.3.4 Accessibility was considered for two groups: (a) residents; and (b) workers based on an average accessibility travel time within three ranges: up to 10 minutes; between 10 and 30 minutes; and between 30 and 60 minutes. This method identified the size and scale of the hinterland for each RA in the ‘do- minimum’ and ‘do-something’ scenarios. Additional analysis was then undertaken to investigate the impact on travel times within the hinterland for each RA.

7.3.5 For the purposes of this analysis, commute trips were considered on the basis that they are most likely to be affected by any travel time changes. Travel times from both the AM and PM peak periods of demand were aggregated to provide a single measure of accessibility for each Regeneration Area.

7.3.6 The Report identified a 4% increase overall of the Slough hinterland population that can be accessed within 60 minutes from the RA, with a corresponding 1% increase in population accessibility for trips travelling to the RA; the changes in travel times between the ‘do-minimum’ and ‘do-something’ scenarios range from -10% to 0.6% change in trips from the RA and -3.6% to -0.1% change in trips to the RA. The 10% reduction in journey time appears in the 30-60 minute category.

7.3.7 The Regeneration Report concludes that there is an overall slight positive impact on RAs which are close to the Scheme, which has been translated into a recording of a slight beneficial impact of the Scheme in paragraph 14.4.19 of the ES (Application Document Reference 6-1).

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7.4 In terms of social sustainability the Scheme can be anticipated to make Slough more accessible. By contrast, improving the motorway could work against SBC’s aim of reducing reliance on private car use and encouraging a shift towards more sustainable modes. Making use of the M4 easier and more convenient for car commuters could reduce the relative attractiveness of public transport and active transport (i.e. walking and cycling) alternatives. Any increase in traffic and congestion on linked, local routes including the A4 could delay buses and create further hazards for pedestrians and cyclists. This could discourage use of sustainable travel alternatives, resulting in a reduced level of social inclusion, deteriorating environmental conditions and a downturn in public health.

Highways England's Comment

7.4.1 Table 10 of the Planning Statement (Application Document Reference 7-1) notes that the strategic case for providing additional capacity on the M4 within the Thames Valley was first examined in the Thames Valley Multi-Modal Study ("TVMMS") published in 2003, which sought to identify the most effective means of addressing current and future transport-related problems in the Thames Valley and looked at the contribution that all modes of transport and traffic management might make, including road, rail, bus and light rail. The TVMMS recommended demand management measures on the M4 motorway either in isolation, or in combination with increased levels of public transport provision. Some of the public transport projects identified in the TVMMS have either been completed or are currently underway. The Scheme is therefore part of a wider package of demand management measures on the M4 motorway that include increased levels of public transport provision.

7.4.2 Table 10 of the Planning Statement (Application Document Reference 7-1) states that “the Scheme will….ensure that the availability of public transport is unaffected by the Scheme as far as possible, both during the construction and operational phases”. During the construction phase, paragraph 13.4.1 of the Outline Construction Environment Management Plan (“CEMP”) (Appendix 4.2A of the ES) (Application Document Reference 6-3) identifies that construction workforce travel plans will be prepared by the contractor to encourage the use of sustainable modes of transport where possible and to reduce the impact of workforce travel on the local road network and associated communities.

7.4.3 The opportunities for the development of links with the delivery of other public transport projects, such as the Slough Mass Rapid Transit scheme (“SMaRT”) is an area for further consideration.

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7.4.4 The Government has recognised that there is a range of options to address the identified need for improvement to the strategic road network. These options are described in more detail in Table 1 of the NN NPS. However, it considers that relying solely on alternatives (or a combination of alternatives as set out in Table 1 of the NN NPS) is not viable or desirable as a means of managing that need. In particular, as stated in Table 1:

Demand Management

“Non-fiscal measures to influence the use of the national road network for journeys, including provision of information and traffic management are important. New technologies can also help improve and make more efficient use of capacity. However, demand management and technology can only make a contribution to alleviating the damaging effects of congestion across the network. Some areas have undertaken significant demand constraint measures or used smarter choices to reduce car use, which has resulted in reductions in urban traffic. However, this has not translated into significantly less pressure on the Strategic Road Network.”

Modal Shift

“Across Government, policies are being implemented and considered which encourage sustainable transport modes including public transport, significant improvements to rail capacity and quality, cycling and walking. However, it is not realistic for public transport, walking or cycling to represent a viable alternative to the private car for all journeys, particularly in rural areas and for some longer or multi-leg journeys. In general, the nature of some journeys on the Strategic Road Network means that there will tend to be less scope for the use of alternative transport modes.”

7.4.5 Whilst stating the case for the need for improvements to the strategic road network and rejecting the assertion that measures such as demand management and modal shift can provide the complete solution, there is clearly a recognition that these measures are complementary and play an important part of a wider transport policy.

7.5 Some benefits to pedestrians and cyclists could be provided by the Scheme as outlined in para. 5.23. The Scheme could also contribute to improving public transport by assisting SBC in achieving bus priorities at Junction 5 as described in paras. 8.4 and 8.5.

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Highways England's Comment

7.5.1 Public transport schemes such as that described by the local authority fall outside the scope of the Scheme. It is therefore not proposed to incorporate the provision of bus priorities within the Scheme.

7.6 The Socio-Economic Report published by HE is fundamentally flawed in its consideration of the impact and effect on modal shift as well as its incomplete and inadequate assessment of behaviour change and attitudinal research. The M4 does not operate in isolation and therefore the impact on the associated road network and local travel behaviour is a key consideration for the granting of a DCO.

Highways England's Comment

7.6.1 The purpose of the Socio-Economic Report is set out clearly in paragraph 1.1.2 of the document (Application Document Reference 7-2), namely to set out the strategic socio-economic context, provide a detailed socio-economic profile of the area through which the Scheme passes and to present detailed consideration of the construction and operational effects of the Scheme as they relate to community and private assets. Whilst it is acknowledged that the M4 does not operate in isolation and that the motorway interacts with the associated road network and local travel behaviour, which are are important factors for consideration, the Socio-Economic Report does not, and is not intended to, assess these issues specifically.

7.6.2 The Traffic Forecasting Report for the Scheme describes the modelling methodology used to undertake forecasts and provides the key statistics associated with those traffic forecasts. Future year public transport demand matrices were developed in order to assist with the identification of modal shift. Modal share statistics presented in Tables A-31 and A-32 of the Traffic Forecasting Report show an insignificant impact on modal share as a result of the Scheme in both the Opening Year (2022) and Design Year (2037).

7.6.3 The potential impact on the surrounding highway network during construction of the Scheme was considered in a Technical Note provided as Appendix 6.3 of the ES (Application Document Reference 6-3). Two sets of assessments were undertaken, the first making use of the M3/M4 strategic traffic model replicating the approach undertaken for the economic assessment of the Scheme, and the second assessment using QUADRO (Queues and Delays at Roadworks). Both models have suggested that there is potential for the diversion of vehicles during the AM and PM periods, but that there is less need for traffic to divert between these peak periods. The paper concludes that,

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whilst traffic flows diverting from the M4 during roadworks (i.e. not in the operation of the Scheme) potentially may exceed 1000 vpd (vehicles per day) overall, it is more likely to occur during peak periods and to be dispersed onto a multitude of routes, with increases on specific routes not exceeding 100 vpd.

7.7 In the Socio-Economic Report reference is made to Slough having the highest concentration of SMEs and large businesses, with further reference given to the Slough Trading Estate. In contrast it has the lowest self-containment. This indicates the travel behaviour of individuals who work in the Borough and suggests people who work in Slough travel from other neighbouring areas and further afield. There is thus a significant dis-benefit associated with improving traffic flow and capacity on the M4 as it makes for a more attractive form of travel to and from Slough. This statement is further corroborated when considering the Department for Transports analytical paper, ‘Understanding the drivers of road travel: current trends in and factors behind roads use’, where reference is made to the evidence that despite increased car ownership, people are driving less in urban areas. This correlation is partly due to increased levels of congestion, with further reference made to attitudinal research and the preference for car journeys. https://www.gov.uk/government/publications/understanding-the-drivers- of-road-travel-current-trends-in-and-factors-behind-roads-use

Highways England's Comment

7.7.1 The purpose of the Scheme is to address congestion on the M4 Motorway. As such, it represents an investment in transport sand in a mode which will remain of importance, irrespective of other initiatives. It should be noted that the disbenefit alleged is that people travel to and from Slough. Either is beneficial to Slough since the Borough operates as part of the wider Thames Valley region. Slough relies on in- and out- commuting.

“In particular, we may expect traffic in urban areas to grow less strongly, as rising populations and growing incomes continue to push up the number of people wanting to drive, but the availability of public transport services keeping traffic growth down, alongside more limited road capacity. In contrast, we would expect continued strong growth on rural roads and the SRN, where traffic has grown strongly up until now, and the availability of alternative modes of transport are more limited.”

7.7.2 Paragraphs 3.3.4 and 3.3.5 of the Socio-Economic Report (Application Document Reference 7-2) describe the Travel to Work Areas ("TTWAs") through which the Scheme passes and note key statistics relating to the reduction in number of TTWAs in the UK over time as the trend in more and longer distance commuting increases as well as the level of self-containment of an area. As noted in SBC's representation above, the self-containment figure for Slough is comparatively low (68.1%) compared to other TTWAs in the immediate vicinity (for example Reading and Bracknell, which has a self-

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containment figure of 73.1%). The East Berkshire Local Economic Assessment referred to in paragraph 3.3.6 of the Socio-Economic Report (Application Document Reference 7- 2) notes that there is a daily net inflow of commuters to East Berkshire of over 16,000; there is also considerable movement within East Berkshire itself, with a high proportion of individuals moving from Royal Borough of Windsor and Maidenhead to Slough. There are several factors at play here, of which a key factor relates to the skills level of the resident population – the Royal Borough of Windsor and Maidenhead being home to a highly skilled population, whilst Slough experiences a relatively high proportion of residents with no qualifications or lower level qualifications, with resultant implications in terms of the types of skills than is average regionally.

7.7.3 Whilst on the face of it, there might appear to be “a significant dis-benefit associated with improving traffic flow and capacity on the M4 as it makes for a more attractive form of travel to and from Slough” the reality is that the interdependencies which exist within East Berkshire are more complex. The East Berkshire LEA states that Slough’s strong local economy is dependent upon the supply of highly skilled labour from surrounding local authority areas and equally, the areas providing the highly skilled labour are currently dependent upon Slough to provide suitable jobs for their residents.

7.7.4 The paper produced by the Department for Transport in January 2015 ‘Understanding the drivers of road travel: current trends in and factors behind roads use’ does indeed provide useful information relating to changes in road traffic and car use over time. The paper states that urbanisation and increases in population density have been found to bring down car demand in recent decades; there is also some evidence to suggest that increasing congestion in urban areas is contributing to the levelling off of traffic in these areas and that more people in these areas are travelling by public transport instead. However, in contrast, attitudinal research suggests that the car is still seen as the most desirable mode of transport due to its flexibility and convenience. The paper concludes that falling car use may have been attributed in recent years to rising costs (for example of fuel) and ‘flat’ incomes, whereas the outlook for the future is that traffic may continue growing again at an aggregate level, albeit at a slower rate than previously due to factors such as urbanisation and access to different forms of travel.

7.7.5 There clearly remains a need both for a strategic road network that is functioning efficiently as well as access to a diverse range of transport modes on other routes - the Scheme is clearly targeted at delivering this first part of the equation.

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7.8 Mitigating measures are therefore needed to influence an uptake towards sustainable modes of travel, and to encourage and achieve behaviour change during the construction of the M4 Smart scheme in anticipation of its operational launch. These funds can also aide in promotional activity on the use of Smart motorways to residents who are likely to make motorway journeys as part of their daily commute, thus addressing some of the safety concerns mentioned previously. This could also be utilised to raise awareness and support activity to mitigate the negative impact during the construction phase/s of the scheme.

Highways England's Comment

7.8.1 Mitigating measures are only required to be identified in the case of a significant adverse effect upon a given receptor. Slough has not identified such an effect. On the contrary, the analysis above demonstrates the importance of the functioning of the Project.

7.8.2 The deployment of Highways England’s regulated public funds to influence an uptake towards sustainable modes of travel in Slough falls outside the scope of the Scheme. Promotion of the proper use of SMart motorways is also a matter addressed by Highways England itself. Nevertheless, continued dialogue between Highways England and organisations responsible for delivery of emerging sustainable transport projects remains important.

7.9 The contribution from HE for mitigating this effect is suggested to be £22.5 million during a 5 year construction period (taken as 4% of the est. build cost as referenced in the Socio-economic Report) to be divided by junction and the affected local authorities to take a corresponding share of funds for each junction that impacts on their locality. As an alternative mechanism, the amount corresponds to £2.05 million per authority when divided equally or £12.3 million for the Thames Valley Berkshire Local Enterprise Partnership. The circa £410k per annum for each authority will be used to address the issues highlighted in section 7.8.

Highways England's Comment

7.9.1 As noted in Highways England's response to paragraph 7.8 above, Highways England considers that mitigating measures fall outside the scope of the Scheme. On that basis, Highways England does not consider that it would be appropriate for it to fund local authorities as set out in this representation.

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8. OTHER MATTERS

Scheme Programme and Cumulative Effect of Other Strategic Infrastructure Schemes

8.1 The Socio-Economic Report APP-090 identifies a number of developments in the vicinity of the Scheme under the heading ‘Future Conditions’ in the link-by-link assessment in Section 4. Future developments at the Slough Trading Estate are identified as are Crossrail, the Mayor of London’s ‘Opportunity Areas’ at Heathrow and the Riding Court Farm sand and gravel site (see 4.10 for SBC’s comments on the location of the Riding Court overbridge). SBC believes that consideration of the M4 DCO application should take account of 3 other strategic infrastructure developments:

(a) Western Rail Link to Heathrow scheme (Network Rail project for new rail tunnel, leaving the Great Western Main Line between Langley and Iver, connecting to the airport; subject to public consultation in early 2015; business case now being refreshed for formal DCO application);

(b) Heathrow Express (HEx) depot at Langley (a proposal forming part of the High Speed Rail [London West Midlands] Bill, Additional Provision of July 2015); and

(c) Heathrow North West Runway scheme (recommendation of the Airports Commission Final report, July 2015).

8.2 All three schemes directly affect the Borough and, although there are many uncertainties attached each, their future delivery has the potential to coincide with implementation of the M4 Smart Motorway scheme as shown in Table 4 below:

Table 4: Programming of Strategic Infrastructure Schemes

Scheme Start of construction End of Programme Note Overlap below construction Rail Western Rail Link to Heathrow Spring/ Summer end 2021 HEX, M4, 1 (WRLtH) 2017 Heathrow HEx Langley depot June 2017 July 2019 WRLtH, M4 2 M4 Smart Motorway J7 to J4b Bridges March 2018 July 2020 WRLtH, HEX, 3 Heathrow Verge works July 2019 June 2020 Central reserve works July 2020 May 2021 Heathrow NW Runway M4/M25 road diversion April 2020 Jan 2024 WRLtH, M4 4 A4 Bath Road diversion April 2020 May 2023

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Scheme Start of construction End of Programme Note Overlap below construction New NW runway Sept 2021 June 2025 New T6A terminal Feb 2023 April 2026 1. National Rail website http://www.networkrail.co.uk/heathrow/

2. HS2 Hybrid Bill Supplementary Environmental Statement and Additional Provision 2 Environmental Statement July 2015

3. APP-107: HE EDR-Annexes B Outline Construction programme

4. Heathrow Airport Ltd: Technical Appendices 3 submission to Airports Commission (based on Government giving go ahead Sept 2015)

8.3 SBC is concerned about the cumulative effect of these strategic projects and suggested during the Smart Motorway consultation period that the sequence of Scheme activities put forward in the outline construction programme should be reviewed. In the light of recent events (i.e. Airports Commission Final Report and HS2 Bill Additional Provision both published in July this year). SBC believes that this review is more urgent.

Highways England's Comment

8.3.1 Paragraph 16.4.1 of the ES (Application Document Reference 6-1) states that the assessment of combined and cumulative effects has been based on the available information for other developments that are planned/proposed, for example in relation to construction and operation timescales, traffic generation and the nature and scale of the development and associated impacts. Appendix 16.1 of the ES (Application Document Reference 6-3) presents the information available at the time of writing the ES (January 2015).

8.3.2 The Western Rail Link to Heathrow proposal was announced on 5 February 2014 following consideration of four options by Network Rail. At the time the assessment for the Scheme was undertaken, the proposal was at “early stages of development” following its inclusion in the Route Utilisation Strategies published in March 2010. As such, it was not at a sufficiently developed stage to be included in the cumulative assessment for the Scheme, and did not come within the guidelines set out in DMRB for those committed, reasonable foreseeable developments that should be included in the assessment. It is understood an application may be brought forward in due course. Any application for the construction of the Western Rail Link will be required to take the M4 improvement scheme into account when assessing the effect of their proposals, rather than the reverse.

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8.3.3 Similarly, the requirement to relocate the Heathrow Express depot is dependent on the HS2 Bill receiving Royal Assent and, without such approval, it cannot be regarded as committed. However, the sidings site is identified in the local development framework for the London Borough of Hammersmith and Fulham as a site for employment and potentially some element of residential use. Accordingly, it was included in the development sites assessed within the traffic model.

8.3.4 In respect of the proposal for a third runway at Heathrow Airport, the recommendations of the Airports Commission are under consideration by the Government. There are two potential solutions under consideration for Heathrow Airport and a third at Gatwick Airport. As such, there are no proposals capable of being assessed at this stage.

8.3.5 It is acknowledged that other proposals, some of which, as highlighted above, are likely to be significant developments with wide reaching impacts should they be progressed, will emerge over time. The ES and associated documents must, by necessity, operate a ‘cut-off’ point up to which other developments can be included within the assessment but following which a separate assessment cannot be made. The development site collation process was ‘frozen’ in February 2014 at which time the detailed model development took place.

Junction 5 Langley Interchange and SBC SMaRT scheme

8.4 Junction 5 at Langley Interchange is the eastern end of Phase 1 of SBC’s SMaRT scheme (Slough Mass Rapid Transit, not to be confused with the Smart Motorway project) which will deliver a dedicated bus lane and enhanced bus services along the A4 corridor between Junction 5, Slough town centre and Slough Trading Estate to the west. This runs roughly parallel to the route of the M4 and will provide commuters with increased opportunity to switch from cars to public transport along this important east-west corridor; this in turn would be expected to improve traffic conditions and air quality. Construction of Phase 1 is programmed to start in December 2015 with funding from the Government’s Local Growth Fund and support from the Thames Valley Berkshire Local Enterprise Partnership.

Highways England's Comment

8.4.1 At its meeting on the 18 July 2013, the Berkshire Local Transport Body approved a list of prioritised schemes, of which those ranked 1st to 4th and 5th equal were approved for Programme Entry. Included within those approved for Programme Entry were two stages of the SMaRT scheme: Slough Trading Estate to Three Tuns and Three Tuns to Brands Hill. Although funding had yet to be secured, the projects were adjudged as reasonably

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foreseeable in the Scheme uncertainty log and, on that basis, included in the model forecasts. Accordingly, the increased opportunity to switch from cars to public transport has been taken account of in the Scheme's forecasts for traffic.

8.5 Phase 2 is planned to continue SMaRT from Junction 5 to Heathrow to provide a fast attractive public transport link between Slough and the airport. Backing has been received from Thames Valley Berkshire Local Enterprise Partnership and Heathrow Airport Ltd to carry out a feasibility study of Phase 2 as the prelude to preparation of the business case. To connect the SMaRT scheme from Slough to Heathrow means crossing under the M4 using the Junction 5 roundabout. SBC is seeking the cooperation of HE in achieving, as part of the Scheme, an efficient and effective way for buses to pass around this roundabout with minimum delay. This would be regarded by SBC as one of the ‘reasonable opportunities to deliver environmental and social benefits’ foreseen in NN NPS para 3.3 as well as giving due consideration to ‘impacts on local transport networks and policies’ as stated in NN NPS para. 5.211. (See also SBC’s comments on management of traffic signals at this roundabout in 5.10 of this LIR).

Highways England's Comment

8.5.1 The traffic signals at junction 5 are operated by Reading BC and maintained by SBC. As outlined in para 5.12.1 Highways England recognises the importance of the junction 5 roundabout as well as the connection to Heathrow Airport. Highways England agrees that the strategic interface between the M4 and the local road network needs to operate effectively in order to best manage traffic in the SBC area. Highways England will continue to work closely with SBC to manage traffic most effectively in the vicinity of junction 5 and will be happy to have discussions on how to ensure that buses travelling through the junction do so efficiently and effectively.

8.6 In addition to benefits for public transport at the roundabout SBC considers that there are further opportunities to enhance conditions for pedestrians and cyclists in the vicinity of Langley Interchange. In relation to the right of way that traverses the roundabout the Engineering and Design Report states that ‘the three lanes of the roundabout and the footpaths under the bridge will be kept operational for the bulk of the construction period with only short-term closures anticipated’ (APP-096, 7.8.20). However it is understood that when closures are necessary the aim is to find a suitable surface level diversionary route for pedestrians and cyclists. There may be scope for a route if this kind to become a permanent feature and offering an alternative to the current subway and extensive ramps.

Highways England's Comment

8.6.1 Highways England will engage with SBC in relation to temporary diversion routes. As part of these discussions, practical measures for the Scheme to

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deliver a positive legacy for active transport associated with the Scheme can be addressed, although these measures cannot themselves be part of the Scheme.

Windsor Branch Line Services

8.7 The Slough- Windsor branch railway is an important link between the two towns and provides essential connections with First Great Western Main Line services to London and Reading. SBC notes that widening works on the railway bridge are programmed to take 27 months but is uncertain about the impact on rail services on the branch line and on Network Rail’s plans for electrification.

Highways England's Comment

8.7.1 The impact of the Scheme's construction works on rail services will be minimal and would be restricted to a small number of weekend closures needed to carry out works that cannot be safely carried out with services running or completed during normal out-of-service periods at night. This would include operations such as installation of beams over the railway.

8.7.2 Highways England considers that the draft DCO provides sufficient safeguards as it incorporates Network Rail's standard protective provisions at Schedule 9, Part 3 of the draft DCO.

8.7.3 On 8 July 2015, Network Rail confirmed that "Network Rail is content with the protective provisions in the draft Order being in the same form as for previous Highways England schemes"

8.7.4 Further detail can be found in Highways England's responses to Network Rail's response to the Examining Authority's First Written Question, and to Network Rail's written representation.

Cost of Legal Orders

8.8 A number of Side Road Orders and Public Rights of Way diversion/temporary closure orders will need to be processed, for which the legal and staff costs to SBC will need to be reimbursed by HE.

Highways England's Comment

8.8.1 Highways England has not previously reimbursed authorities for their costs associated with processing orders and does not consider that this approach should change for the Scheme.

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APPENDIX 1 Environmental barriers and air quality

1. “The air quality benefits at roadside receptors from installation of barriers have been the subject of significant research in recent years and there is little doubt of their benefits in reducing off-road exposure. The recent “Dutch Air Quality Innovation Programme” (1) concluded that “Noise barriers reduce concentrations of nitrogen oxides and airborne particulates along motorways. That is the conclusion drawn by (international) air quality experts based on the measurements obtained during two years of large-scale practical trials.” This work is recognised by Defra as having relevance to the UK and there is no doubt that roadside barriers would have a beneficial effect on air pollution and health outcomes at the most compromised receptors along the M4. Indeed I would suggest that barriers could be an effective solution to existing exceedances of EU Limit Values given the conditions along the M4 through Slough.

Highways England's Comment

1.1 The study referenced does conclude that noise barriers can have an effect in reducing exposure to pollutants emitted from major roads. The study does however acknowledge: “The results are valid for the experimental location and the period in which measurements were conducted. Additionally, measurements were performed on a barrier of limited length (100m) in a rural setting. These results cannot therefore be applied one-on-one to an arbitrary location or period, so further study is required.”

1.2 Highways England is currently carrying out its own trials on the effectiveness of barriers in reducing pollution at sensitive receptors near to major roads.

1.3 The reductions identified in that study found were 14% reduction for NO2 10m from the barrier, dropping to 7% by 28.5m.

1.4 Whilst some receptors in the study area are 20m or less from the M4 e.g. those at Upton Park (receptor A322 identified above), other receptors modelled along the mainline between junction 6 and junction 7 are approximately 70m or more set back from the M4 and at junction 6, the closest receptor to the east (A253) is more than 30m from the slip road and more than 60m from the mainline, with receptors A247-A252 further back again.

1.5 On that basis, it is almost certain that any reductions in NO2 at these receptors would be even less than the reductions identified in this study.

2. Slough Borough Council have instructed me to prepare a screening air quality dispersion model to test the potential benefits of installing such barriers along the M4. The model only seeks to assess the magnitude of benefit and does not seek to mirror the Environmental Statements submitted to date.

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Highways England's Comment

2.1 Although Ricardo AEA / Slough Borough Council acknowledge that they were not attempting to reproduce the numbers in the ES, such large differences in pollutant concentrations predicted (as identified in paragraph above) will also have a knock-on effect on the estimated improvements from associated proposed mitigation measures. In addition, there is no information available in Slough Borough Council’s Local Impact Report or the Appendix on the modelling parameters used or any assumptions that have been made. Therefore, these numbers must be considered with caution.

3. The results indicate potential air quality benefits amounting to >10% at some receptors depending on location and barrier height. This is not a trivial reduction (equivalent in exposure terms to reducing road traffic by >10%) and should be explored further, particularly as there remains significant uncertainty in emissions data from the road fleet, and in light diesel vehicles in particular. Diesel vehicles are now known to emit significantly more emissions than previously thought and this should factor into mitigation decisions regardless of the outcomes of dispersion modelling. In my professional experience working for government, industry and Local Authorities in the UK for the past 10 years I am not aware of a single instance of predicted future emissions reductions in the road fleet coming to pass in reality- the reverse is true where NOx emissions have been repeatedly scaled upwards over time to reflect evidence of real world conditions. In basic terms there is good reason to suspect that emissions reductions assumed in the fleet by 2022 (as in the ES) will not transpire in reality, as has been the case in recent years (2).

Highways England's Comment

3.1 Changes of more than 10% have only been identified with barrier heights of 6m and 8m. It is unlikely that noise barriers with a height of 6m or 8m would be suitable for installation along the Scheme route due to potential issues regarding foundations, stability and visual impacts.

3.2 Indeed, the average predicted improvements in pollutant concentration presented in Appendix 2 of Slough Borough Council’s Local Impact Report are around 1.4% (max. 4%) with a 2m barrier and 3% (max 9%) with a 4m barrier.

3.3 It should be noted that there are already some noise barriers along these sections of the M4 and so any additional benefits in these locations would be reduced. The majority of the noise barriers in this area are between 1.8m and 2m in height. The locations of these barriers, with reference to the receptor results presented in the Slough Borough Council Local Impact Report Appendix are:

 Along M4 eastbound on slip at junction 7 near indicative receptor point Roadside28;

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 Along the M4 eastbound carriageway between junctions 6 and 7, from junction 7 to Wood Lane overbridge near indicative receptor points Roadside23 - Roadside27 and Roadside46- Roadside48;

 Along the mainline M4 eastbound carriageway through junction 6 either side of the bridges, near indicative receptor points Roadside17, Roadside18 and Roadside31;

 Partway along the eastbound off slip at junction 6, near indicative receptor points Roadside19 and Roadside20;

 Partway along the eastbound on slip at junction 6, near indicative receptor point Roadside 16;

 Along the M4 eastbound carriageway from junction 6 to Herschel Park, with a gap over the railway bridge, near indicative receptor points Roadside13 – Roadside15 and Roadside32;

 Along the M4 westbound carriageway between junctions 5 and 6 alongside the properties to the northern edge of Datchet, off Slough Road/B376, near indicative receptor points Roadside10, Roadside 11, Roadside33 – Roadside35 and Roadside49 – Roadside50;

 Along the M4 westbound carriageway between junctions 5 and 6 alongside the properties to the northern edge of Datchet, off Majors Farm Road. However, no indicative receptor points have been modelled in this appendix;

 At the mainline end of the eastbound off slip at junction 5, near indicative receptor point Roadside9;

 From the A4 round the junction and along the M4 eastbound on slip at junction 5, near indicative receptor points Roadside5 – Roadside7, Roadside39 and Roadside41; and

 Approximately 2/3 of the way along the M4 westbound off slip at junction 5 from the motorway towards the roundabout near indicative receptor points Roadside2 – Roadside4, Roadside40, Roadside42 - Roadside43 and Roadside51 to Roadside54.

3.4 In addition to the above, the following noise barriers are proposed to be installed as part of the noise mitigation when the Scheme is constructed, with a height of 2m in most places, unless indicated otherwise below:

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 Along the M4 eastbound carriageway between junctions 6 and 7 from Wood Lane overbridge to junction 6 near indicative receptor points Roadside20 – Roadside21 and Roadside29 – Roadside30;

 Along the M4 both sides of the carriageway over the railway bridge near Upton Park;

 Along the M4 westbound carriageway between junctions 5 and 6 at The Myrke (at height 2.4m) near indicative receptor point Roadside 12; and

 Along both carriageways of the M4 through junction 5, near receptor points Roadside1, Roadside5 – Roadside8, Roadside39 and Roadside41.

3.5 Details of the above can be found on Drawing 12.2, Sheets 10 to 13 of the ES (Application Document Reference 6-2).

3.6 The vast majority of the receptors modelled in this indicative view of potential noise barrier effects are therefore already close to barriers of a 1.8m-2m height. The results presented below appear to assume there are no barriers present in the base case.

3.7 Over the last few years, the rates of improvement anticipated by the Department for Environment, Food and Rural Affairs (“Defra”) have not been realised as quickly as anticipated. This is due to the dieselisation of the vehicle fleet to a greater extent than

previously anticipated, with the associated higher emissions of NOx and NO2, and also

because of the gap between the anticipated laboratory based rates of NOx emissions compared

with real world rates of NOx emissions.

3.8 The approach utilised in the assessment of future air quality recognises this, and therefore Highways England has not assumed that in the future all improvements in air quality (i.e. rates of improvement in vehicle emissions etc.) will occur at the rate anticipated by Defra. In particular, the treatment of future air quality has been considered through the updated air

quality advice on the assessment of future NOx and NO2 projections known as long term trend (“LTT”) analysis (Interim Advice Note 170/12 v3 ‘Updated air quality advice on the

assessment of future NOx and NO2 projections for users of DMRB Volume 11, Section 3, Part 1 ‘Air Quality’’), which assumes only a portion of improvements in air quality assumed by Defra will occur. This is described in paragraphs 6.2.57 to 6.2.60 of the ES (Application Document Reference 6-1).

4. The results of our initial barrier modelling study are broadly in line with work done in the Netherlands (3). The plot below shows the relative change in concentrations for a perpendicular wind at roadside receptors- the reduction in concentrations is about 15% or more and the benefit extends to quite

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significant distance from the road. These benefits have the potential to offer significant reductions in exposure to air pollution along the M4 in Slough.

Highways England's Comment

4.1 The improvements due to barriers presented in Figure 3 above are described as the impact when wind is perpendicular (90o) to the noise barrier. As in reality the wind will not always be travelling perpendicular to the noise barrier, actual reductions in pollutant concentrations would be lower. The results presented above are for a 3.7m barrier. The predicted results presented in this appendix predict a maximum reduction of 9% (average 3%) with a 4m barrier, which is considerably lower than the improvement presented in Figure 3.

5. Dispersion models are inherently uncertain, and so in light of the continued presence of exceedances along the M4 in 2022 we would suggest that further investigations into the usefulness of roadside barriers is warranted. In fact barriers would seem to offer a safeguard to receptors who could be exposed to more pollution by virtue of sources being moved closer to them under the proposed scheme. Dispersion models submitted with the ES may show that only small changes in exposure are expected but their accuracy in such circumstances is open to debate and under such conditions mitigation can be used to a) protect people from exposure to more pollution and b) offer improvements to even the pre-scheme conditions.

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Highways England's Comment

5.1 The use of barriers is not currently an approved technique for mitigating air quality effects on Highways England road schemes. This is because there is insufficient evidence as to the effectiveness of this type of measure. Therefore, based on both the viability of the measure and that the effect is not quantifiable, it is not an appropriate measure to use, especially as the Scheme is not anticipated to have a significant effect on air quality. However, this is something that Highways England is currently investigating in a field trial as a potential future targeted mitigation measure.

5.2 The overall operational assessment of significance of the Scheme is set out in paragraph 6.15.16 and Tables 6.21 and 6.22 of the ES (Application Document Reference 6-1). The air quality assessment does not predict a significant effect on sensitive receptors as a result of the Scheme, and therefore no air quality specific mitigation measures are proposed

6. Additionally Slough Borough Council have a statutory duty to reduce air pollution and protect public health so they should seek mitigation in these circumstances where benefits are obvious and scientifically demonstrable- this is one such instance in my view. By providing mitigation in this instance there is potential to not only reduce the impacts of the Smart Motorway scheme itself, but also to reduce the impacts of the motorway in general on the receptors who live at its side.

Highways England's Comment

6.1 As outlined in the response to paragraph 2.9 above, the air quality assessment of the Scheme in Chapter 6 of the ES reached the conclusion that the Scheme would have no significant impact on air quality. On that basis, Highways England does not consider that further mitigation is needed to "reduce the impacts of the Smart Motorway scheme itself".

6.2 With regard to reducing the impacts of the motorway in general on the receptors which surround it, Highways England considers that many of the potential benefits presented here embedded in the Scheme. It is not necessary to apply them directly, since they are likely to be achieved through speed controls that may be present during the peak hours with the Scheme in operation.

6.3 Similarly, noise barriers are currently in place along the M4 and additional barriers are proposed for noise mitigation already and therefore the types of potential benefits suggested may already be achieved.

7. All discussion provided above apply in principle to NO2, but the same benefits will hold true for PM10, PM2.5, carbon monoxide, black carbon, VOCs, polycyclic aromatic hydrocarbons and a whole range of other less obvious air pollutants which are all emitted by road traffic. Therefore mitigation would additionally protect public health by limiting chronic exposure to these pollutants as well. In my view

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the health benefits of mitigation could be obscured by focussing solely on NO2 even in instances where exceedances of these other pollutants are not present. For instance demonstrable benefits to health are achieved by reducing exposure to PM10 and PM2.5 even at levels below EU Limit Values (the WHO Guideline Values (4) for these pollutants are significantly below the UK adopted standards- for PM2.5 the annual mean value is 10ugm3 as opposed to 25ugm3 as adopted by Europe and the UK).

Highways England's Comment

7.1 The air quality assessment has considered the key pollutants with respect to vehicle emissions as required by the Design Manual for Roads and Bridges. The air quality assessment for the

Scheme includes predictions of annual mean pollutant concentrations of PM10. The highest 3 3 concentration of annual mean PM10 across the entire study area is 26.3 µg/m (23.5 µg/m within Slough), with a maximum Scheme contribution of 0.3 µg/m3.

Refs (1) http://laqm.defra.gov.uk/documents/DutchAirQualityInnovationProgramme.pdf (2) http://uk-air.defra.gov.uk/assets/documents/reports/cat05/1108251149 110718 AQ0724 Final report.pdf (3) http://www2.hoevelakenbereikbaar.nl/MilieuZaken/luchtkwaliteit/Examples-air-quality- measures-near-roads-in-europe-200507.pdf (4) http://apps.who.int/iris/bitstream/10665/69477/1/WHO SDE PHE OEH 06.02 eng.pdf

Dr Scott Hamilton Knowledge Leader Urban Scale Air Quality Modelling and Assessments

Email: [email protected] Direct Dial: +44 (0)1235 753 716 Mobile: +44 (0)7968 707 112 Reception: +44 (0)1235 753 000

Ricardo Energy & Environment 18 Blythswood Square, Glasgow, G2 4BG, UK Website: ee.ricardo.com

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Deadline III - Response to Local Impact Reports 113 Highways England