A417 Air Balloon Roundabout Restricted Movements Improvement Option

Highways Agency March 2012

Contents

1 Introduction 1

2 Proposed Improvements 2

3 Traffic Assessment and Delays 3

4 Environment and Air Quality 8

5 Risks and Impacts 10

6 Economic Assessment 13

7 Measurement of Success 16

8 Implementation 18

9 Signing Strategy 19

10 Operational Issues 20

11 Conclusions and Recommendation 21

Figures

Figure 1 Location Plan Figure 2 Scheme Proposals Figure 3 Proposed Temporary Signs Figure 4 Changes to Traffic Flows AM Peak Figure 5 Changes to Traffic Flows PM Peak Figure 6 Locations of Impacts

1 Introduction

1.1 PURPOSE OF REPORT 1.1.1 The Highways Agency is investigating ways of improving the traffic flow at the Air Balloon roundabout to reduce congestion and queuing. This report has been produced to document the feasibility and impacts of a proposal to achieve this by preventing vehicles turning right or U-turning from the A417 Birdlip Hill.

1.2 LOCATION 1.2.1 The Air Balloon roundabout is situated to the southeast of Gloucester at Crickley Hill, near Birdlip and connects the A436 to the A417. (See Figure 1). Adjacent to the roundabout there are two residential properties (1 & 2 Air Balloon Cottages), a public house (The Air Balloon) and two field accesses. 1.2.2 The roundabout lies within the Cotswolds Area of Outstanding Natural Beauty (AONB) and is close to Crickley Hill Country Park. The Cotswold Way (national footpath) and Gloucestershire Way both cross the A417 at the Air Balloon roundabout. 1.2.3 Gradients on the approach to the roundabout from Gloucester, on Crickley Hill are steep, (approximately 9%) and slow moving heavy goods vehicles (HGVs) travelling uphill can cause queuing issues despite the provision of a climbing lane.

1.3 BACKGROUND 1.3.1 The Air Balloon roundabout is situated on the only remaining section of single carriageway on the A417/A419 route between the M4 (Jnc.15) and M5 (Jnc.11a). Traffic volumes on the A417 at this location are currently between approximately 28,000 and 34,000 vehicles per day of which approximately 12-14% are HGVs. Queues occur regularly at the roundabout and its approaches during morning and evening peak periods. 1.3.2 The roundabout is in an Air Quality Monitoring Area (AQMA) and therefore any alterations must not worsen air quality. 1.3.3 The A417 Cowley to Brockworth Bypass Improvement, which avoided the need for trunk road traffic to pass through the Air Balloon Roundabout, was developed over a number of years. However, despite the clear need to improve this section of the A417 being recognised, the major scheme could not be taken forward through the previous Regional Funding allocation process, because of the £250M scheme cost. The proposal to restrict movements at Air Balloon for the benefit of strategic traffic movements has come out of further work to consider more affordable measures that could be implemented within a shorter timescale.

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2 Proposed Improvements

2.1 RESTRICTED TURNING MOVEMENTS (A417 FROM SWINDON TO A436 SEVEN SPRINGS) 2.1.1 This option was identified at the Highways Agency / Gloucestershire County Council Network Management workshop held on 18 November 2009 where it was suggested the circulatory carriageway could be modified by extending the Crickley Hill splitter island to the roundabout central island as shown in Figure 2. 2.1.2 Under this arrangement traffic is prevented from turning right or making U-turns from the A417 Cirencester arm and prevented from U-turning from the A436 Seven Springs arm. Therefore traffic from A417 Crickley Hill could enter the roundabout unimpeded from any circulatory traffic. 2.1.3 Consequently, there would be fewer gaps in traffic on the circulatory carriageway across the A436 Seven Springs arm, reducing the opportunity for entry onto the roundabout. The reduced flow onto the roundabout from A436 Seven Springs would give traffic from the A417 Cirencester greater opportunity to enter the roundabout.

2.2 EXPERIMENTAL ARRANGEMENTS 2.2.1 It is proposed the improvements are initially implemented under an experimental traffic regulation order. This would allow impacts of the proposals to be fully understood before commitment to implement the scheme on a permanent basis. 2.2.2 Therefore, in the initial experimental situation the proposed works are; x Water filled barriers to extend the splitter island on Crickley Hill to the roundabout central island (Figure 2), x Temporary yellow signs on A-frames with sand bags giving advanced warning of the proposal and route direction information (Figure 3). 2.2.3 The benefits and impacts of the experimental arrangements would be monitored so that an informed decision could be made regarding progression to the permanent arrangements. Information required to carry out this monitoring would include journey times along the A417, changes in air quality at the AQMA monitoring sites and changes to traffic at key locations on the local road network.

2.3 PERMANENT SCHEME ARRANGEMENTS 2.3.1 Figure 2 shows the scope of works for permanent arrangements at Air Balloon Roundabout which include the following; x Kerbed extension to splitter island on Crickley Hill to the roundabout central island. Top soil and grass seed to splitter island and gated / restricted paved route through for emergency vehicles, gritters and emergency diversion routes. x New permanent route signing, warning signing and carriageway markings.

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3 Traffic Assessment and Delays

3.1 EXISTING TRAFFIC CONDITIONS 3.1.1 The Air Balloon roundabout is a key junction on the A417/A419 between Swindon and Gloucester and causes much of the congestion on this length. 3.1.2 Queuing traffic is evident on all three arms of the roundabout during morning and evening peak hours and journey time delays of 20 minutes on the A417 in both directions is not unusual. 3.1.3 The two way annual average daily traffic (AADT) on the A417 is currently 34,200 vehicles per day on Crickley Hill and 28,700 vehicles per day on the link towards Swindon. 3.1.4 To assess the proposed improvements, SATURN traffic modelling has been carried out using the model developed for the A417 Cowley to Brockworth Bypass Improvement which in turn, was developed from the joint HA/Gloucestershire County Council Central Severn Vale traffic model. Although somewhat dated and not re- validated, the model is considered adequate for this assessment. The model predicted traffic in 2010 and this has been used to represent current traffic flows. Traffic flows for the morning and evening peak hours at the Air Balloon roundabout have been obtained from the model and are shown in Tables 3.1 and 3.2 below.

Table 3.1: Air Balloon Roundabout SATURN 2010 AM Peak Hour Traffic Flows To A417 A436 Seven A417 Total Gloucester Springs Cirencester From (Crickley Hill) (Birdlip)

A417 Gloucester 0 937 1534 2471 (Crickley Hill) A436 Seven 591 0 305 896 Springs

A417 Cirencester 1059 520 0 1579 (Birdlip) Total 1650 1457 1839 4946

Table 3.2: Air Balloon Roundabout SATURN 2010 PM Peak Hour Traffic Flows To A417 A436 Seven A417 Total Gloucester Springs Cirencester From (Crickley Hill) (Birdlip)

A417 Gloucester 0 518 1020 1538 (Crickley Hill) A436 Seven 766 0 479 1245 Springs

A417 Cirencester 1019 351 0 1370 (Birdlip) Total 1785 869 1499 4153

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3.1.5 The above data from the SATURN model has been compared with the automatic traffic count data from the DBFO counters as shown in Table 3.3

Table 3.3: Comparison of SATURN Flows with DBFO Counters Peak Road Section Direction SATURN DBFO Difference Period 2010 Counter Flow Flow (vehs/hr) (vehs/hr) AM A417 Crickley Hill Uphill 2471 1756 +715 (+41%) Peak A417 Crickley Hill Downhill 1650 1444 +206 (+14%)

A417 Birdlip Uphill 1839 1451 +388 (+27%) A417 Birdlip Downhill 1579 1270 +309 (+24%) Total 7539 5921 +1618 (+27%) PM A417 Crickley Hill Uphill 1538 1677 -139 (-8%) Peak A417 Crickley Hill Downhill 1785 1496 +289 (+19%) A417 Birdlip Uphill 1499 1451 +48 (+3%) A417 Birdlip Downhill 1370 1270 +100 (+8%) Total 6192 5894 +298 (+5%)

3.1.6 Table 3.3 above shows that the SATURN 2010 flows are higher than flows recorded by the DBFO traffic counters in 2011, except for the PM peak travelling up Crickley Hill where the SATURN flow is 139 vehicles (8%) lower than the DBFO counter. Apart from this exception the SATURN flows are in the range of 8% to 41% higher than the counters. Day to day variations in peak hour flow is normal at Air Balloon and given the uncertainty in predicting growth in traffic, using the 2010 SATURN flows which are higher than 2011 counted flows gives a degree of robustness to the assessment. 3.1.7 In addition to consideration of the traffic flows at the Air Balloon roundabout, this report considers changes in traffic levels at key points on the local network as a result of the proposed scheme. Figures 4 and 5 show the predicted traffic flows at key points, based on the 2010 SATURN model flows, the flow increase or decrease and percentage change.

3.2 EXISTING RIGHT TURNING TRAFFIC A417 CIRENCESTER TO A436 SEVEN SPRINGS / LECKHAMPTON HILL 3.2.1 The SATURN 2010 traffic flows given in Tables 3.1 and 3.2 show 520 vehicles per hour turn right from A417 Cirencester to A436 Seven Spring / Leckhampton Hill in the morning peak and 351 vehicles per hour in the evening peak. 3.2.2 This volume of traffic amounts to 11% of the total traffic arriving at the roundabout in the morning peak and 8% in the evening peak.

3.3 PREDICTED TRAFFIC WITH PROPOSED IMPROVEMENTS 3.3.1 Tables 3.4 and 3.5 below show the predicted traffic flows at Air Balloon roundabout as derived from the SATURN model when testing the proposed improvement.

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Table 3.4: Air Balloon Roundabout AM Peak Hour SATURN 2010 Predicted Traffic Flows with Improvement To A417 A436 Seven A417 Totals Gloucester Springs Cirencester From (Crickley Hill) (Birdlip) A417 Gloucester Movement not 1179 1539 2718 (Crickley Hill) permitted A436 Seven 579 Movement not 317 896 Springs permitted A417 Cirencester 1494 Movement not Movement not 1494 (Birdlip) permitted permitted Totals 2073 1179 1856 5108

Table 3.5: Air Balloon Roundabout PM Peak Hour SATURN 2010 Predicted Traffic Flows with Improvement To A417 A436 Seven A417 Totals Gloucester Springs Cirencester From (Crickley Hill) (Birdlip)

A417 Gloucester Movement not 546 1051 1597 (Crickley Hill) permitted A436 Seven 763 Movement not 478 1241 Springs permitted A417 Cirencester 1248 Movement not Movement not 1248 (Birdlip) permitted permitted Totals 2011 546 1529 4086

3.3.2 Figures 4 and 5 show the predicted traffic flow, the change in flow and the percentage change on selected roads in the modelled AM and PM peak hours as a result of the proposed improvement. The changes are described below. Leckhampton Hill 3.3.3 On Leckhampton Hill northbound towards Cheltenham traffic is reduced by 229 vehicles per hour in the AM peak hour and by 280 in the PM peak. This is equivalent to reductions of 39% and 85% respectively. The southbound flows on Leckhampton Hill are marginally increased by 26 and 12 vehicles per hour in the AM and PM peak respectively, equivalent to 11% and 4% respectively. Ermin Way 3.3.4 It is predicted the traffic flows would reduce by 60 vehicles in the AM peak hour and by 30 vehicles in the PM peak hour on Ermin Way with the proposals, equivalent to reductions of 18% and 10% on the link respectively. A40 Cheltenham 3.3.5 Traffic flow is shown to reduce by 93 vehicles on the A40 to the east of Cheltenham in AM peak hour with no change shown for the PM peak.

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A436 to Seven Springs 3.3.6 The model predicts reductions in the morning and evening peak hours within the range of 28 to 48 vehicles per hour in each direction, equivalent to reductions of 4% and 6% respectively. A417 South of Birdlip Junction. 3.3.7 On the A417 south of Birdlip junction the proposals change reduce the northbound traffic by 111 vehicles in the AM peak hour and 119 vehicles in the PM peak hour, both equivalent to reductions of 8%. This is as a result of traffic transferring to other routes between Cirencester to Cheltenham. Southbound the flows are virtually unchanged. A417 Crickley Hill. 3.3.8 A417 Crickley Hill shows the greatest change as a result of the proposed improvements. In the morning peak hour traffic increases uphill by 244 vehicles and downhill by 470 vehicles; a two way flow increase of 714 vehicles per hour, equivalent to a 17% increase in traffic on the link. 3.3.9 In the PM peak hour traffic increases uphill by 56 vehicles and downhill by 219 vehicles; a two way flow increase of 275 vehs per hour, equivalent to 8% increase on the link. 3.3.10 The increase in traffic on Crickley Hill has two causes; traffic from A417 who currently turn right at Air Balloon roundabout from A417 Birdlip approach having to travel down A417 Crickley Hill and U-turn at the A46 before travelling back up to the Air Balloon roundabout and additional traffic because of the improved journey time.

3.4 JOURNEY TIME CHANGES 3.4.1 To predict the possible journey time benefits of the proposals, network journey times have been assessed using the SATURN model and ‘before’ and ‘after’ tests have been carried out using ARCADY. 3.4.2 Journey times through the roundabout for A417 traffic are expected to reduce in the order of 1 to 2 minutes per vehicle on average in the peak hours. 3.4.3 Maximum queue lengths are predicted to reduce by up to 120 vehicles equivalent to maximum journey time savings of approximately 5 minutes. Table 3.6 lists the predicted journey time savings at the Air Balloon Roundabout.

Table 3.6 Journey Time Changes at Air Balloon Roundabout Road Section Peak Hour Average Journey Peak Hour Maximum Journey Time Changes Time Changes A417 Crickley Hill -1.1mins AM; no change PM -3mins AM; no change PM A417 Birdlip -1.6mins AM; -2.4mins PM -4.8mins AM; -5.4mins PM A436 Seven Springs +0.1mins AM; +0.2mins PM +0.2mins AM; +0.4mins PM

3.4.4 Although the A417 shows journey time savings at Air Balloon roundabout, the overall journey time across the network increases. This is because the network has been reduced and traffic must therefore be using less advantageous routes. Table 3.7 below shows the additional journey times in free flow traffic conditions based, on route planning software, for different routes affected by the proposals.

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Table 3.7 Additional Journey Times (free flow traffic conditions) Additional Additional Journey Journey Journey Journey FROM Via TO Time Distance Distance Time (mins) (miles) (Miles) (Mins)

Existing layout 24 17.2 - A46 roundabout U-turn 31 21.7 4.4 6 A419 (South of A417 to A46, A46 Shurdington Leckhampton 29 20.1 2.9 5 Cirencester) A435 to Seven Springs, A436, via Ullenwood to B4070 41 19.5 2.3 17

Existing layout 20 11.8 - Daglingworth A46 roundabout U-turn 26 16.2 4.4 6 (north of A417 to A46, A46 Shurdington Leckhampton 25 14.6 2.9 5 Cirencester) A435 to Seven Springs, A436, via Ullenwood to B4070 34 14.7 2.9 14

Existing layout 24 10 - Bisley A46 roundabout U-turn 30 14.4 4.4 6 (east of A417 to A46, A46 Shurdington Leckhampton 29 13 2.9 5 Stroud) Brockworth (B4070, Little Witcombe) 30 12.1 2.1 6

3.4.5 From Table 3.7 above it can be seen that U-turning at the A417/A46 roundabout is a 4.4 mile detour that typically takes 6 minutes, in free flow conditions. 3.4.6 However not all traffic would U-turn at the A417/A46 roundabout as some, having reached the A46, would turn right towards Cheltenham. This diversion would add an additional 2.9 miles or 5 minutes on a journey to Leckhampton. 3.4.7 Using the A435 between Cirencester and Seven Springs as an alternative route to the Air Balloon adds 2 miles and 17 minutes to a journey to Leckhampton. 3.4.8 For journeys from the Bisley area to Leckhampton the shortest alternative route is via Birdlip Hill and the A46 at Brockworth. This adds 2.1 miles and 6 minutes to the journey. 3.4.9 The impact of additional journey times, distance and inconvenience on properties in the vicinity of the roundabout are considered in Chapter 5 ‘Risks and Impacts’.

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4 Environment and Air Quality

4.1 ENVIRONMENTAL IMPACTS 4.1.1 As the proposals only involve local traffic management changes to the exiting roundabout and do not require land, nor involve carriageway widening there are no significant environmental impacts arising from the proposals. Table 4.1 below reports the expected environmental impacts arising from the scheme.

Table 4.1 Summary of Environmental Impacts Environmental Impact Comment Factor

Air Quality Slight Traffic flow at Air Balloon AQMA is expected to increase. On its own this beneficial could lead to increased air pollution, however the reduction in stop-start and queuing traffic is expected to more than offset this impact giving a slight improvement.

Noise Slight Increased traffic flow on Crickley Hill outside Air Balloon Cottages and Adverse adjacent to Air Balloon public house and other local properties. However reduction in stop start traffic conditions would reduce engine noise.

Greenhouse Slight Traffic model shows a slight increase in network journey time and distance Gases Adverse travelled measured across the whole of the network as a result of the diversion routes. Therefore a slight increase in vehicle emissions can be expected when measured across the whole of the network.

Landscape Neutral Works are proposed at the existing roundabout or at locations where existing network signing is already in place.

Townscape Neutral No impacts.

Heritage Neutral Barrow Wake view point and Emma’s Grove Scheduled Ancient Monument are situated to the south of Air Balloon roundabout. There would be impacts on access from these sites to areas such as Leckhampton Hill or A436 Seven Springs with the proposals. However, the number of journeys affected is low. No visual impacts or land impacts on these sites.

Biodiversity Neutral No works are proposed outside the existing carriageway or verge areas.

Water Neutral No changes to existing drainage catchment area or outfall. Environment

Physical Fitness Neutral Removal of queues would make it easier for pedestrians to cross the A417. However this would be offset against increase in traffic flow on A417 Crickley Hill. Theoretically cyclists are affected in the same way as motorists wishing to turn right from A417 to A436. However some cyclists may choose to dismount and cross the roundabout on the footways rather than travel the diversion route to the A46 junction. Numbers of cyclists are low. Journey Slight Improved journey time on A417 by 1 to 2 minutes per vehicle on average in Ambience – beneficial the peak hours. Maximum journey time savings of 5 minutes predicted on the Trunk Road trunk road.

Journey Slight Increased delay predicted for A436 approach to roundabout and re-routing of Ambience – Adverse local traffic is required as a consequence of roundabout restrictions. County Roads

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4.2 COTSWOLD AONB 4.2.1 The Air Balloon roundabout is located on the western edge of the Cotswold Escarpment and in the AONB. The restricted turns proposed at the roundabout would be implemented with due consideration to the AONB and measures such as provision of new signing and traffic bollards would be kept to the minimum.

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5 Risks and Impacts

5.1 LOCAL IMPACTS

5.1.1 A detailed risk impact assessment would be undertaken prior to implementing the turning restriction at the Air Balloon roundabout. Meanwhile, impacts arising from the proposed traffic restrictions on local properties, villages and the National Public Right of Way have been considered and are reported in the following paragraphs. Figure 6 shows the locations on plan where impacts have been identified.

5.2 AIR BALLOON PUBLIC HOUSE 5.2.1 Removal of the U-turn facility at the Air Balloon roundabout means that traffic exiting from the public house wishing to travel southbound would have to travel to the A46 junction to make a U-turn. This adds 4.4 miles and typically 6 minutes to the journey. The exit from the public house on the A417 is left turn out only because the right turn is not appropriate for the number of lanes to cross and the volume and speed of traffic. Currently, traffic heading southbound from the public house U-turns at Air Balloon roundabout. 5.2.2 The 6 minute diversion to the A46 junction may encourage some traffic to attempt to turn right onto the A417 rather than suffer the long U-turn route. If this occurred the access splitter island and bellmouth could be reshaped to force the left turn out. Junction re-shaping works would be minor; costing in the order of £5,000, subject to statutory undertakers’ works not being required. 5.2.3 There is a risk that traffic from the car park may attempt to exit from the public house access onto Crickley Hill, turning right for routes southbound. However this access is not permitted for use by customers under a planning agreement and reinstatement of the bollards preventing use of this access from the car park should be pursued with the public house.

5.3 CRICKLEY HILL RIDGE 5.3.1 Vehicles leaving Crickley Hill Ridge to head southbound on the A417 may turn right however it is considered many turn left out and U-turn at the Air Balloon roundabout as it can be difficult to cross the A417. However under the proposals it is expected that vehicles would choose to turn right out rather than make the 4.4 mile (6 minutes) diversion to A46 junction for U-turn. 5.3.2 The number of vehicles wishing to turn right out from Crickley Hill Ridge is low. Mitigation measures are not required.

5.4 FOUR WINDS 5.4.1 The proposed restrictions would mean northbound vehicles wishing to turn right into Four Winds would no longer have the option to U-turn at Air Balloon roundabout. Given the distance to the A46 it is probable more vehicles would turn right into Four Winds.

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5.4.2 An alternative route can be provided from the local Shab Hill Road by re- opening a closed length of highway and this is being pursued regardless of the Air Balloon proposals. This would allow the existing junction with the A417 to be permanently closed.

5.5 COLD SLAD 5.5.1 Under the proposals an increase in U-turning traffic may occur at the Cold Slad access as an alternative to travelling to the A46 junction for U-turn. 5.5.2 As mitigation, U-turns at this location could be banned by a traffic regulation order and signed. Physical measures to enforce the ban are not possible as the right turn needs to be retained. Improvements to this junction have been considered in the past but no achievable solution has been identified. 5.5.3 The increase in traffic flow on Crickley Hill may increase the difficulty in turning in or out of Cold Slad. Mitigation is not considered necessary.

5.6 GROVE FARM 5.6.1 The increase in A417 traffic may increase the difficulty of turning in or out of Grove Farm. Mitigation is not considered necessary. 5.6.2 Modifications to this access have been considered in the past to limit use to left-in, left-out only, but no achievable solution has been found. Prohibition of right turns in could be considered but physical measures to prevent the manoeuvre would not be possible.

5.7 AIR BALLOON COTTAGES 5.7.1 There would be an increase in traffic passing the properties on Crickley Hill however removal of some slowing/braking actions at the roundabout is expected to give a slight improvement in air quality and noise locally to the roundabout. 5.7.2 Vehicular access to Air balloon Cottage No. 2, from the A417 northbound and A436 would be affected by the restricted movement, requiring a U-turn at the A46. 5.7.3 Mitigation measures are not available.

5.8 NATIONAL AND LOCAL PUBLIC RIGHTS OF WAY 5.8.1 There would be slight increased difficulty in crossing the A417 Crickley Hill as a result of the higher traffic flow and because the southbound flow would not be required to giveway at the roundabout. 5.8.2 The existing splitter island would be increased in size and would offer some mitigation to crossing pedestrians and the reduced queuing may assist.

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5.9 FIELD ACCESS (AT ROUNDABOUT AND A417 SOUTH OF ROUNDABOUT) 5.9.1 With restricted turns at the roundabout some farm machinery & plant will be required to travel further on the A417 to and from field accesses in the immediate area of the roundabout. This would include slow heavy farm vehicles climbing Crickley Hill which currently do not have to do so when travelling to and from the Cirencester direction. 5.9.2 The numbers of farm machinery making these manoeuvres are low and mitigation measures are not considered necessary.

5.10 BIRDLIP VILLAGE 5.10.1 Routes to and from Birdlip village would be maintained under the proposals without change. Traffic modelling shows a reduction in traffic flows on Ermin Way making the proposals beneficial in terms of traffic flow through the village. Some journeys from Birdlip would require additional journey distance and time, for example to Seven Springs or the east side of Cheltenham.

5.11 ELKSTONE 5.11.1 Some traffic may re-route via Elkstone under the proposals. However the route comprises sections of narrow lane with steep gradients (Bubb’s Hill) and is inappropriate as a diversion route for trunk road traffic. 5.11.2 The existing 7.5T weight limit prevent HGVs from diverting via Elkstone and due to the nature of the route only a small increase in light vehicles is expected from those affected by the proposals. Conversely, the expected reduction in delay northbound at the Air Balloon roundabout should reduce the number of vehicles using this cut-through at present. Overall the traffic flow through Elkstone is not expected to change significantly. 5.11.3 Before and after classified traffic surveys are recommended for the route via Elkstone so that the impact can be assessed.

5.12 LECKHAMPTON HILL 5.12.1 The traffic model shows a reduction in traffic on Leckhampton Hill with the proposals. However residents would be required to travel an extra 2.9 miles (5 minutes) on journeys from A417 south travelling via the A46 Shurdington to Cheltenham, rather than turning right at the Air Balloon roundabout.

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6 Economic Assessment

6.1 SCHEME COSTS 6.1.1 Costs for the temporary experimental scheme at 2011 Q4 prices, comprising water filled barriers, lockable bollards, chevron signing, route signing, advanced signing, and traffic management, are estimated as follows: Item Cost Estimate (2011 Q4 Prices) Contract Costs Preliminaries and traffic management £4,000 Traffic signs, barriers and bollards £34,000

Sub Total £38,000

Costs for consultation, communication strategy, AQ £25,000 assessments, temporary scheme preparation, design, safety audits and supervision cost. Land Costs Nil VAT Nil Statutory Undertakers Nil Sub Total £63,000 Inflation (assume 2012/13) implementation Nil Optimism Bias (25% of scheme costs) £15,750

‘Temporary’ Scheme Total £78,750 6.1.2 The permanent scheme costs at 2011 prices are estimated as follows: Item Cost Estimate (2011 Q4 Prices) Contract Costs Preliminaries & Traffic Management £16,800 Site Clearance (inc kerbs and rbt blocks) 1,800 Drainage and Ducts £1,710 Pavements £15,606 Kerbs and Footways £390 Traffic Signs £38,000 Electrical Work £400

Sub Total £74,706

Consultation, Communication Strategy, AQ Assessments, £15,000 Design, Scheme Preparation, Safety Audits and Supervision Cost Land Costs Nil VAT Nil Allowance for Statutory Undertakers £5,000 Sub Total £94,706 Inflation TBA (Construction year required) Optimism Bias (25% of scheme costs) £23,700

‘Permanent’ Scheme Total £118,406

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6.1.3 The total scheme cost for the temporary and permanent works is therefore estimated to be £197,200.

6.2 JOURNEY TIME BENEFITS 6.2.1 For economic assessment the Highways Agency PAR version 6.2 has been used as well as network costs being calculated using the SATURN model. PAR Assessment 6.2.2 ARCADY modelling has been carried out to assess journey times through the Air Balloon roundabout for both the existing situation and proposed scheme and Table 3.6 of this report shows the changes in journey times. Based on these values an average journey time saving has been calculated for the AM and PM peak as shown in tables 6.1 and 6.2 below:

Table 6.1 Journey Time Savings AM Peak Roundabout Approach Traffic flow Journey time Total journey (pcu / hr) savings per vehicle time savings (mins per pcu) (pcu mins)

A417 Crickley Hill 2471 1.1 2718 A436 Seven Springs 896 -.01 -90 A417 Birdlip 1579 1.6 2526

Total 4946 - 5154 Weighted Average - 1.04 -

Table 6.2 Journey Time Savings PM Peak Roundabout Approach Traffic flow Journey time Total journey (pcu / hr) savings per vehicle time savings (mins per pcu) (pcu mins)

A417 Crickley Hill 1538 0 0 A436 Seven Springs 1245 -0.2 -249 A417 Birdlip 1370 2.4 3288 Total 4153 - 3039 Weighted Average - 0.73 -

6.3 COST BENEFIT 6.3.1 The total traffic entering the roundabout and average journey time savings for a single AM peak hour and a single PM peak hour have been entered into the PAR worksheet and, based on this data, an opening year journey time benefit at the roundabout of £405,000 (in 2002 prices) has been calculated. In fact the ‘peak hours’ invariably last for longer than 1 hour increasing these savings proportionally. 6.3.2 However this assessment, using PAR, does not consider costs associated with additional journey time and distance for other traffic on the network that divert as a consequence of the restrictions at the roundabout, as discussed in the following section.

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Network Assessment (SATURN) 6.3.3 To assess total journey time costs across a wider network than simply the Air Balloon roundabout site the SATURN model has been used with monetary costs attributed to journey time and journey distance. These network costs are shown below in Tables 6.3 and 6.4 below.

Table 6.3 AM Peak Hour Network Costs (2002 Prices) 2010 Flows Costs - Additional Costs - Existing Proposed Costs Arrangements Network Statistics Arrangements Total Travel Time, all pcu, £ £189,541 £190,188 £647 Travel Distance, all pcu, £ £94,661 £94,951 £290

Total Additional Costs £937

Table 6.4 PM Peak Hour Network Costs (2002 Prices) 2010 Flows Costs Existing Costs Proposed Additional Network Statistics Arrangements Arrangements Costs Total Travel Time, all pcu, £ £176,335 £177,589 £1,254 Travel Distance, all pcu, £ £92,440 £92,438 -£2

Total Additional Costs £1,252

6.3.4 Therefore the overall predicted additional journey time costs across the road network as a result of the Air Balloon scheme proposal in the AM and PM peak is £2,189 (in 2002 prices) per week day. 6.3.5 SATURN modelling data is not available for inter-peak periods and weekends so total peak hour costs have been factored using AADT values for A417 Birdlip, giving a dis-benefit estimated cost of £3.7M (2002 prices) across the network in a year. Note that the additional journey time and distance to travel as a result of the restricted turns at Air Balloon roundabout would occur 24 hours a day but journey time savings are only expected during the peak hours. Other Considerations 6.3.6 The journey time assessments do not take into account other economic advantages that would come from the reduced journey times for strategic traffic, principally the stimulation of economic activity which leads to increased employment. Swindon Gloucester and Cheltenham are regional centres of population and employment and therefore improvement of this route, which provides links between them, is vitally important for stimulating development.

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7 Measurement of Success

7.1 JOURNEY TIME DELAY 7.1.1 One of the key measures of success for the scheme would be reducing journey time delay on the A417 in both directions at the roundabout. 7.1.2 Measurement of existing journey times on the A417 would be required before making the changes and the recommended method for gathering this information is to record vehicles by reception of Bluetooth signals on the Air Balloon approaches beyond the point where queues occur. Approximately a third of all traffic on this route could be expected to emit a Bluetooth signal, giving a good sample size for recording journey time. 7.1.3 Following the changes at the roundabout collection of journey time data should continue so that ‘before’ and ‘after’ assessments can be carried out.

7.2 AIR QUALITY 7.2.1 Data from the Air Quality Management Area (AQMA) at Air Balloon Cottages is required to enable before and after assessments. Proposals must not make air quality worse than at present. 7.2.2 AQMA data from the local authority would be required to carry out this assessment. 7.2.3 As well as monitoring air quality at the cottages, the relationship between air quality and traffic flow should be assessed as it is expected the free flow traffic arrangements onto the roundabout on Crickley Hill would reduce air pollution relative to traffic flow. Traffic flow from the DBFO counters is available for this comparison.

7.3 ROAD TRAFFIC ACCIDENTS 7.3.1 The proposals are not expected to have an impact on the number of accidents occurring at the Air Balloon or the wider network however accidents on all the affected routes should be monitored.

7.4 IMPACTS 7.4.1 Section 5 of this report describes impacts expected from the proposals. Evaluation of these impacts would be required, including consultation with the affected parties and before and after site visits to record changes. 7.4.2 Impacts to be assessed include: x Impact of re-routing for local accesses:

o Air Balloon public house, o Air Balloon field access, o Air Balloon Cottages, o Four Winds, o Cold Slad,

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o Grove Farm. x Impacts / risk of additional traffic through villages:

o Elkstone, o Birdlip. x Impacts of additional journey time due to re-routing:

o Journeys to Leckhampton x Non-Motorised Users Impacts

o Cyclists turning right A417 to A435, o The Cotswold Way and Gloucestershire Way cross the A417 at Air Balloon roundabout.

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8 Implementation

8.1 EXPERIMENTAL TRAFFIC ORDER 8.1.1 An Experimental Traffic Regulation Order (ETRO) is recommended for implementing the proposed restriction at Air Balloon roundabout. Based on a similar order for the M4/M32 roundabout junction restriction, the ETRO would; …close part of the A417 Air Balloon roundabout situated between the entry to and exit from the A417 towards Gloucester so that traffic from Gloucester can join the roundabout unimpeded by vehicles on the driver’s right. 8.1.2 An ETRO is valid for up to 18 months when it needs to be made permanent or removed. This would allow the scheme to be trialled on an experimental basis giving sufficient time for the benefits and impacts of the proposals to be assessed and allow objections to be considered.

8.2 CONSULTATION AND COMMUNICATION STRATEGY 8.2.1 A communication strategy should be developed jointly with Gloucestershire County Council. It should consider how to inform motorists and how consultation with the local MPs, County Councillors, Parish Councils, emergency services and Gloucestershire County Council Highways department should be carried out. 8.2.2 As a minimum, advance warning for motorists should be provided in a manner similar to a temporary road closure.

8.3 M4 / M32 JUNCTION BRISTOL 8.3.1 The M4 / M32 junction at Bristol is an example of a site where restricted turns are in place at a roundabout. At this site the restriction has been put in place so that M32 traffic has free flow onto the roundabout in the same way as is proposed for A417 Crickley Hill. 8.3.2 It is understood that the arrangements at M4 / M32 junction have been successful in bringing about journey time savings without any adverse effects on safety. If required, further research of this site could be carried out with the assistance of the Highways Agency.

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9 Signing Strategy

9.1 ROUTE SIGNING 9.1.1 The signed diversion route for the restricted movements at Air Balloon would take traffic down A417 Crickley Hill to the A417 / A46 grade separated junction at Brockworth. Figure 3 shows temporary sign faces that would be appropriate for this diversion at Air Balloon. 9.1.2 Diversion route signing would be required at the A417 / A46 junction to show a U-turn back to Air Balloon for traffic to Stow-on-the Wold and Oxford. For traffic travelling to Cheltenham and Leckhampton it is recommended that they are signed to turn right at this junction to take the A436 northbound. As well as signing on the approach to the slip road of this junction, new signing at the A46 roundabout would also be required. 9.1.3 It is not recommended that any diversion routes are signed via the A435 because in free flow conditions this would cause more journey time delay and the route itself is not as high a standard as the dual carriageway sections of the A417. However some drivers may choose to travel on the A435, following satnav or local road knowledge depending on their particular destination; for example to the east side of Cheltenham.

9.2 ADVANCE WARNING SIGNING 9.2.1 For such a change to the road network it is normal to place temporary signs to warn drivers that changes are due in 4 to 6 weeks’ time. 9.2.2 Such signs would be recommended on the A417 approaches, the A436 approach and Leckhampton Hill approach to the roundabout.

9.3 NEW ROAD LAYOUT AHEAD 9.3.1 In addition to the signs described above ‘New Road Layout Ahead’ signs would be recommended for the approaches to Air Balloon Roundabout. 9.3.2 A detailed signing strategy should be agreed jointly with Gloucestershire County Council, as the local highway authority.

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10 Operational Issues

10.1 WINTER MAINTENANCE 10.1.1 RMS, the DBFO Company who manages this route requested the proposals allow for winter gritting lorries to U-turn from the A417 Birdlip approach for operational reasons. 10.1.2 This could be provided by using removable / fold down bollards or a padlocked gate as part of the extension to the splitter island.

10.2 EMERGENCY ROUTES 10.2.1 The U-turn facility described above may also have benefits in the event of an emergency road closure being required on A417 Crickley Hill or possibly as routes for the emergency services. 10.2.2 Consultation with the emergency services would be required as part of scheme design development, to fully understand their requirements.

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11 Conclusions and Recommendation

11.1 CONCLUSIONS 11.1.1 Although the proposals do not add to the road network and would have some local dis-benefits, in overall terms it is considered the journey time savings it produces are desirable and would provide some benefit to economic growth within the area. 11.1.2 Some 8000 minutes of queuing time would be saved every day by strategic road traffic during the single peak hours alone, with a value of some £½M per year. Based on these savings the proposals would pay for themselves in less than 6 months. 11.1.3 Before proceeding a number of tasks need to be completed including a detailed risk assessment, agreement of a signing strategy and a communication strategy. Air quality monitoring requirements need to be fully agreed with Cotswold District Council as the authority responsible for managing the Air Quality Management Area (AQMA) including the use of the Experimental Order period to assess the impact on the air quality. 11.1.4 Gloucestershire County Council are keen to work in partnership with the HA to consider the merits of the scheme and possible implementation in 2012/2013.

11.2 RECOMMENDATION 11.2.1 Subject to funding it is recommended the proposal is taken forward in partnership with Gloucestershire County Council, with a view to implementation as an experimental scheme for delivery in 2012/2013.

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AIR BALLOON ROUNDABOUT

This map is based upon Ordnance Survey material by WSP Civils Ltd. on behalf of the Highways Agency, with the permission of the controller of Her Majesty Stationery Office, Crown copyright. Unauthorized reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Licence No. :GD 272663.

4 1 7

Predicted Flow 634 Predicted Flow 1099 Predicted Flow 634 % Change -5% % Change +14% Predicted Flow 1062 % Change +12% % Change +0% Predicted Flow 363 % Change -39% Predicted Flow 251 Predicted Flow 738 % Change +11% % Change -4%

Predicted Flow 2526 % Change +11% Predicted Flow 611 % Change -6%

Predicted Flow 21 Predicted Flow 2037 % Change -16% % Change +30%

Predicted Flow 375 Predicted Flow 247 Predicted Flow 398 % Change -4% % Change -19% % Change +39%

Predicted Flow 1562 Predicted Flow 1300 % Change +1% % Change -8%

Predicted Flow 523 Predicted Flow 619 % Change +2% % Change -3%

Predicted Flow 1004 Predicted Flow 48 % Change +16% % Change -85% Predicted Flow 1132 % Change 0% PredictedFlow 355 Predicted Flow 487 % Change +4% % Change -8%

Predicted Flow 1524 Predicted Flow 878 % Change +4% % Change -3%

Predicted Flow 291 Predicted Flow 1997 % Change +12% % Change -9% Predicted Flow 413 Predicted Flow 9 % Change +40% % Change 0%

Predicted Flow 269 % Change -10%

Predicted Flow 1395 PredictedFlow 1274 % Change -8% % Change -0.4%

AIR BALLOON ROUNDABOUT LECKHAMPTON HILL

C O AIR BALLOON L D COTTAGES

S L A D

CRICKLEY HILL RIDGE

GROVE FARM FOUR WINDS

BIRDLIP VILLAGE

ELKSTONE VILLAGE