A47 WANSFORD TO SUTTON
A47 WANSFORD TO SUTTON
PCF STAGE 3 | | 11/09/20 Notice
This document has been prepared on behalf of Galliford Try by Sweco UK Ltd for Highways England's Delivery Integration Partners (DiP) Framework. It is issued for the party which commissioned it and for specific purposes connected with the above-captioned project only. It should not be relied upon by any other party or used for any other purpose. Sweco UK Ltd accepts no responsibility for the consequences of this document being relied upon by any other party, or being used for any other purpose, or containing any error or omission which is due to an error or omission in data supplied to us by other parties.
This document contains confidential information and proprietary intellectual property. It should not be shown to other parties without consent from Galliford Try. A47 WANSFORD TO SUTTON
Highways England Programme Leader:
Highways England Project Manager:
Galliford Try Sweco Delivery Integration Partner, Project Manager:
PCF STAGE 3 Supplier:
Document control
Client GALLIFORD TRY
Project A47 WANSFORD TO SUTTON
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Document reference
Revision history
Revision Purpose description Originator Checked Approved Authorised Date
Prepared for: Prepared by:
Galliford Try Sweco UK Ltd Cowley Business Park Grove House Cowley Mansion Gate Dr Uxbridge Leeds Middlesex LS7 4DN UB8 2AL A47 WANSFORD TO SUTTON
Table of contents
1. Introduction 1 1.1 Context 1 1.2 Existing scheme section 2 1.3 Current traffic issues 3 1.4 Scheme objectives 4 1.5 Current stage of the project 6 1.6 The scheme 6 1.7 Purpose of the report 7 1.8 Report structure 7 2. Summary of previous work 9 2.1 Overview 9 2.2 Model area and network 10 2.3 Modelled time periods 12 2.4 User class segmentation 12 2.5 Software used 12 2.6 Assignment procedure and generalised cost parameters 13 2.7 Model calibration and validation 14 2.8 Variable demand modelling 17 2.9 Previous PCF Stage 0-2 traffic forecasting report 17 3. Forecasting approach 20 4. Uncertainty log and forecast years 22 4.1 Introduction 22 4.2 Forecasting at PCF Stage 0-2 22 4.3 Forecasting at PCF Stage 3 22 4.4 Forecast years 22 4.5 Uncertainty log (local area plan data and transport supply data) 23 4.6 Modelled scenarios 25 5. Reference forecast demand 26 5.1 Overview 26 5.2 NTEM growth of car trips 27 5.3 NTEM growth of goods vehicles 28 5.4 Trip generation and distribution for modelled developments 28 5.5 Dependent development 30 5.6 Constraining to district level 31 5.7 Combined background and development trip matrices 31 5.8 Alternative scenarios 32 6. Forecast supply 34 6.1 Introduction 34 6.2 Do Minimum scenario 34 6.3 Do Something scenarios 35 6.4 Forecast network calibration 37 7. Equilibrium demand forecasts 38 7.1 Overview of variable demand response 38 A47 WANSFORD TO SUTTON
7.2 Demand modelling zone aggregation 39 7.3 Types of VDM response 39 7.4 Calibration of the DIADEM model 42 7.5 Journey time elasticity 45 7.6 ‘Pivot point’ method 46 7.7 Generalised cost 47 7.8 Convergence in DIADEM 48 7.9 Outputs from DIADEM 48 8. Assignment results for economic assessment 54 8.1 Introduction 54 8.2 Assignment model convergence statistics 54 8.3 Do Minimum variable demand forecast results 56 8.4 Do Something variable demand forecast results 57 8.5 Key statistics for the core scenarios 61 8.6 Sensitivity testing 62 8.7 Traffic flows 64 8.8 Journey times 64 8.9 Model constraints 66 9. Assignment results for environmental assessment 67 9.1 Required outputs 67 9.2 Speed banding 67 9.3 Use of WebTRIS data 68 9.4 Derivation of average annual traffic flows 69 9.5 Other required outputs 71 9.6 Speed pivoting 71 10. Assignment results for operational performance assessment 72 11. Conclusions 73 Selected validation summaries 75 Sectored demand analysis 79 Trip length distribution changes 103 Uncertainty log for the development zones 109 Stick diagrams 113 Link actual flow differences 117 NTEM v7.2 trip rates – car 130 Demand matrix growth summary table 133 Low and high growth outputs 134
Figures
Figure 1-1: Package Location Plan 1 Figure 1-2: Location of Wansford to Sutton dualling scheme (outlined by the blue region) 2 Figure 1-3: Existing A47 / A1 interchange at Wansford 3 Figure 2-1: Wansford PCF 2-3 study areas 10 Figure 2-2: Wansford traffic model and the buffer area within the area of impact 11 A47 WANSFORD TO SUTTON
Figure 2-3: Top line summary statistics 16 Figure 2-4: Extent of the cordoned Wansford model for Stage 1 18 Figure 2-5: Wansford Paramics model (network defined in red) 19 Figure 3-1: Flowchart of forecasting process 20 Figure 4-1: Major development sites identified in Peterborough local plan 24 Figure 5-1: A47 Wansford Stage 3 development locations in Peterborough 27 Figure 6-1: Wansford model Do Minimum coding change locations 34 Figure 6-2: A47 Wansford to Sutton dualling scheme with further improvements at A1 / A47 Western Roundabout 36 Figure 6-3: Highway network changes in Do Something compared to Do Minimum 37 Figure 7-1: Sectors 50 Figure 7-2: 2025 car trip length distribution – AM peak 53 Figure 7-3: 2040 car trip length distribution – AM peak 53 Figure 8-1: Actual flow difference – DM40 final vs DS40– AM (bandwidth 250PCU/mm) 58 Figure 8-2: Actual flow difference – DM40 final vs DS40 (pivoting to base) – AM (bandwidth 250PCU/mm) 58 Figure 8-3: Actual flow difference – DM40 final vs DS40– IP (bandwidth 250PCU/mm) 59 Figure 8-4: Actual flow difference – DM40 final vs DS40 (pivoting to base) - IP (bandwidth 250PCU/mm) 59 Figure 8-5: Actual flow difference – DM40 final vs DS40– PM (bandwidth 250PCU/mm) 60 Figure 8-6: Actual flow difference – DM40 final vs DS40 (pivoting to base) – PM (bandwidth 250PCU/mm) 60 Figure 8-7: Journey time routes 65 Figure 9-1: Count sites used to create AADT conversion factors 69
Tables
Table 1-1: RIS performance specification and KPIs 4 Table 2-1: Value of time assumptions, pence per minute (PPM, 2010 prices, 2015 values) 13 Table 2-2: Vehicle operating cost assumptions, pence per kilometre (PPK, 2010 prices, 2015 values) 14 Table 2-3: Summary of model calibration and validation 15 Table 2-4: Wansford Paramics model base year specifications for Stage 2 19 Table 4-1: Classification of future impacts 23 Table 5-1: RTF18 goods vehicle growth rates from 2018 28 Table 5-2: Jobs per 100 sqm of GFA 29 Table 5-3: Average TRICs trip rates - A1 29 Table 5-4: Average TRICs trip rates - B1 29 Table 5-5: Average TRICs trip rates – B2 30 Table 5-6: Average TRICs trip rates - B8 30 Table 5-7: Balancing Area Descriptions 31 Table 5-8: Highway Reference Demand at OD Level – Core Scenario AM Peak 31 A47 WANSFORD TO SUTTON
Table 5-9: Highway Reference Demand at OD Level – Core Scenario Inter Peak 32 Table 5-10: Highway Reference Demand at OD Level – Core Scenario PM Peak 32 Table 5-11: Core, low and high scenario definitions 33 Table 6-1: DM network assumptions 35 Table 7-1: VDM parameters / model response and hierarchy 40 Table 7-2: DIADEM logit parameters 43 Table 7-3: DIADEM distribution Lambda (λ) parameter values 43 Table 7-4: Outturn fuel cost elasticity by time period and purpose 44 Table 7-5: Outturn journey time elasticity by time period and purpose 45 Table 7-6: Generalised cost parameters (2010 prices) 48 Table 7-7: DIADEM demand-supply convergence statistics 2025 and 2040 48 Table 7-8: Sector system for VDM analysis 49 Table 7-9: 2040 highway demand (car only) % change between DM and DS - AM 51 Table 7-10: 2040 highway demand (car only) % change between DM and DS - IP 51 Table 7-11: 2040 highway demand (car only) % change between DM and DS – PM 51 Table 8-1: Post VDM assignment convergence statistics 54 Table 8-2: Primary model convergence criteria: final assignment 55 Table 8-3: A47 traffic growth in 2-way AADT 57 Table 8-4: Percentage splits on A47 traffic growth in 2-way AADT 57 Table 8-5: SATURN simulation network overall average speed (km/h) 61 Table 8-6: SATURN simulation network overall total travel distance (PCU.km/h) 61 Table 8-7: SATURN simulation network overall total travel time (PCU.hrs) 61 Table 8-8: Average speed (km/h) low growth, core scenario and high growth opening year 2025 62 Table 8-9: Average speed ((km/h) low growth, core scenario and high growth designing year 2040 63 Table 8-10: Total travel distance (PCU.km/h) low growth, core scenario and high growth opening year 2025 63 Table 8-11: Total travel distance (PCU.km/h) low growth, core scenario and high growth designing year 2040 63 Table 8-12: Modelled journey time results (unit: second) 65 Table 9-1: Motorway speed bands 67 Table 9-2: Non-motorway speed bands 68 Table 9-3: Motorway speed flow curves 68 Table 9-4: Peak hour to period conversion factors 70 Table 9-5: Global conversion factors 70 A47 WANSFORD TO SUTTON
1. Introduction
1.1 Context
1.1.1. As part of Highways England’s Regional Delivery Partnership’s (DIP), Galliford Try has commissioned Sweco as a lead consultant to undertake the PCF stage 3 - Preliminary Design assessment of six improvement schemes within the wider A47 /A12 Corridor Feasibility Study. Six schemes are proposed as part of the A47 corridor improvement programme, including the following:
· A47 Wansford to Sutton · A47/A141 Guyhirn junction · A47 North Tuddenham to Easton · A47 Blofield to North Burlingham · A47/A11 Thickthorn Junction Improvement · A47 Great Yarmouth Junction Improvements
1.1.2. These schemes are part of the Road Investment Strategy (RIS) for the 2015 to 2020 period. Construction is programmed to commence between 2021/22 and 2024/25, depending on the scheme. The requirement of this Package Contract is to progress the schemes through PCF Stage 3 Preliminary Design, and PCF Stage 4 (Statutory Procedures and Powers).
Figure 1-1: Package Location Plan
Source: AECOM & Amey. This Map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
1.1.3. All six schemes were delivered through PCF Stage 0 to 2 by AECOM and Amey. These stages identified a good strategic case for investment as well as a preferred route.
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1.1.4. In PCF Stage 3 Mott MacDonald Sweco Joint Venture (MMSJV) previously undertook the works required to develop a preliminary design.
1.1.5. As part of Highways England’s Regional Delivery Partnership’s (DIP), this work is now overtaken by Galliford Try who has commissioned Sweco as a lead consultant to undertake the PCF Stage 3 to Stage 5 of five progressing schemes, excluding Great Yarmouth Junction. This report details the transport forecasting package available for the PCF stage 3 study which relates to the A47 Wansford to Sutton Improvement Scheme.
1.2 Existing scheme section
1.2.1 The A47 Wansford to Sutton dualling scheme is located between the A1 junction at Wansford and Nene Way Roundabout in Sutton to the west of Peterborough. Figure 1-2 shows the location of the scheme with the major links shown by blue lines.
Figure 1-2: Location of Wansford to Sutton dualling scheme (outlined by the blue region)
Source: SWECO. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
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1.2.2 Figure 1-3 shows an aerial image (from Highways England WebTRIS map view) of the A47 / A1 Interchange at Wansford.
Figure 1-3: Existing A47 / A1 interchange at Wansford
Source: Highways England (WebTRIS Map view)
1.3 Current traffic issues
1.3.1 As described in section 1.1, the A47 corridor varies considerably over its length with a combination of single and dual-carriageway sections and grade-separated and at-grade junctions. The A47 Wansford to Sutton dualling scheme is located between the A1 junction at Wansford and Nene Way Roundabout in Sutton to the west of Peterborough. The 2.4 kilometre stretch of road is currently single- carriageway.
1.3.2 The single-carriageway section of the A47 acts as a bottleneck, resulting in congestion and leading to longer and unreliable journey times. In particular, peak hour congestion is experienced in the eastbound direction in the AM with queuing occurring on the A1 and A47 roundabout approaches. The poor performance of the A47 Wansford to Sutton section has also contributed to a poor safety record. In addition to this, there are a number of known growth hotspots around Wansford as well as along the corridor, and it is considered that this proposed growth will exacerbate the current transport issues experienced along the A47 Wansford to Sutton section. Furthermore, this increase in demand from development growth could worsen any associated economic, environmental and social impacts.
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1.4 Scheme objectives
1.4.1 The genetic objectives established for the A47 Wansford to Sutton dualling scheme identified in the corridor feasibility study are: support economic growth, improve capacity, resilience and safety, and address environmental concerns. These objectives align with the wider RIS Performance Specification which identifies Key Performance Indicators (KPIs) for the network as a whole, described in Table 1-1. The objectives for the scheme have been selected to align with those at the national level.
Table 1-1: RIS performance specification and KPIs
Performance Key performance indicator Additional clarification within RIS specification
Although KSIs have been selected as the key The number of people killed indicator, Highways England should Making the network and seriously injured aim to reduce all incidents. The safer (KSI) on the strategic causation of all incidents should be road network (SRN). investigated.
Number of noise important Ambitious schemes which significantly areas mitigated. improve the environment should become the norm. Further Delivering better performance indicators should be environmental Delivery of improved developed for air quality and CO2 outcomes biodiversity, as set out emissions. Schemes should in the company's demonstrate the aspirational goals of Biodiversity Action the Natural Environment White Plan. Paper.
A narrow KPI has been chosen as there are currently few established metrics for Helping cyclists, assessing accessibility for vulnerable walkers and users. However, it is expected that The number of new or other Highways England will consult with upgraded crossings. vulnerable relevant non-governmental users organisations in order to develop schemes that will improve accessibility.
Average delay is a simplistic measure of the benefits of the network to economic growth. Broader consideration Encouraging should be given to how the SRN can Average delay (time lost per economic support the flow of goods and freight, vehicle per mile). growth improve productivity and competitiveness, as well as helping to unlock key housing and economic development sites.
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Performance Key performance indicator Additional clarification within RIS specification
Currently, the only available metric is the The percentage of pavement National Pavement Condition Keeping the network asset that does not indicator. However, the performance in good require further specification covers all asset classes condition investigation for within the network: pavement, possible maintenance. structures, technology, drainage and geotechnical works.
Network availability: the percentage of the SRN These 2 metrics are chosen to improve the Supporting the available to traffic. management of planned works smooth flow Incident management: (network availability) and improve of traffic percentage of response to incidents that cannot be motorway incidents predicted (incident management). cleared within 1 hour.
Cost savings: savings on capital expenditure.
Delivery plan progress: progress of work, These indicators concern the change in Achieving real relative to forecast set management structure with the efficiency out in the delivery plan, creation of Highways England. and annual updates to that plan, and expectations at the start of Road Period 1.
The percentage of National Road Users' While user satisfaction as measured by Improving user Satisfaction Survey NRUSS has remained high, there satisfaction (NRUSS) respondents has been a downward trend in recent who are very or fairly years. satisfied.
1.4.2 The specific objectives for the A47 Wansford to Sutton Dualling scheme as outlined in Highways England's A47 Corridor Improvements Analytical Requirements Report (May 2018) include the following:
· Supporting Economic Growth - Contributing to sustainable economic growth by supporting employment and residential development opportunities. The scheme aims to reduce congestion-related delay, improve journey time reliability and increase the overall capacity of the A47.
· A Safe and Serviceable Network - Improving road safety for all road users through being designed to modern highway standards appropriate for a strategic road.
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· A More Free-Flowing Network - Increasing the resilience of the road in coping with incidents such as collisions, breakdowns, maintenance and extreme weather. The improved route between Wansford to Sutton will be more reliable, reducing journey times and providing capacity for future traffic growth.
· Improved Environment - Protecting the environment by minimising adverse impacts and where possible deliver enhancements by improving the environmental impact of transport on those living along the existing A47 and by minimising the impact of new infrastructure on the natural and built environment.
· An Accessible and Integrated Network - Ensuring the proposals take into account local communities and access to the road network, providing a safer route between communities for cyclists, walkers, equestrians and other non-motorist groups.
· Value for Money - Ensuring that the scheme is affordable and delivers good value for money.
1.5 Current stage of the project
1.5.1 The A47 RIS schemes were delivered through PCF Stage 0 to 2 by AECOM and Amey. These stages identified a good strategic case for investment, as well as a preferred design. In PCF stage 3, following the previous work undertaken by Mott MacDonald SWECO Joint Venture (MMSJV) in 2017/2018, SWECO have been now fully undertaking the remaining works required to develop a preliminary design since November 2019.
1.6 The scheme
1.6.1 The A47 Wansford to Sutton dualling scheme is located between the A1 junction at Wansford and Nene Way Roundabout in Sutton to the west of Peterborough. The 2.4 kilometre stretch of road is currently single-carriageway. This section of the A47 currently acts as a bottleneck, resulting in congestion and leading to longer journey times and a poor safety record.
1.6.2 Three options were taken to public consultation, including dualling the existing A47 on its current alignment (Option 1), building a new dual-carriageway partly to the north and partly to the south of the existing alignment (Option 2) and building a new dual-carriageway entirely to the north of the existing A47 alignment (Option 3). Option 2 was originally chosen as the preferred option and presented at the statutory consultation undertaken in 2018.
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1.6.3 Since statutory consultation 2018 and ongoing design reviews, some features of the design are unchanged and some aspects have been subject to ongoing development. As a result, Option 3 is now selected as the preferred route instead and so the latest scheme proposal is to provide a new dual-carriageway to the north of the existing A47 alignment.
1.6.4 The latest scheme proposal also includes further improvements at the A1 / A47 Western Roundabout as follows:
· Improved entry from the A1 northbound diverge slip road; · Improved exit to the A47 eastbound; · New Segregated Left Turn Lane (SLTL) between A1 northbound slip road and A47 eastbound; and · New cycle crossing of the A47 west of the roundabout, removing cycle traffic from the A1 overbridge.
1.6.5 An illustration of the full scheme is shown in Figure 6-2.
1.7 Purpose of the report
1.7.1 This report describes the traffic forecasting for only the Wansford to Sutton Dualling scheme and sets out the assumptions on which these forecasts have been based. The outputs of the forecasting work provide:
· The future year design traffic flows · Traffic flows for operational appraisal of the scheme junctions · Traffic impacts across the network and on the A47 corridor · Inputs to the environmental appraisal · Inputs to the economic appraisal
1.8 Report structure
1.8.1 This report is structured as follows:
· Section 2: Summary of previous work – summary of previous PCF Stage work as well as the base year model’s development, calibration and validation · Section 3: Forecasting approach – a brief summary of the overlay forecasting methodology · Section 4: Uncertainty log and forecast years – the scope and main elements of the uncertainty log, explicitly modelled developments and the forecast years
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· Section 5: Reference forecast demand – details of the use of road traffic forecasts (RTF) and national trip end model (NTEM) to create core, low and high reference case scenarios · Section 6: Forecast supply – summary of the assumptions contained in the Do Minimum (DM) and Do Something (DS) models · Section 7: Equilibrium demand forecasts – application of variable demand modelling (VDM) and the results of the Dynamic Integrated Assignment and Demand Modelling (DIADEM) modelling · Section 8: Assignment results for economic assessment – results and analysis of the DS and DM Simulation and Assignment of Traffic to Urban Road Networks (SATURN) assignments · Section 9: Assignment results for environmental assessment – derivation of the environmental assessment information · Section 10: Assignment Results for operational performance – derivation of the operational assessment information · Section 11: Conclusions
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2. Summary of previous work
2.1 Overview
2.1.1 This chapter details the development and calibration of the PCF Stage 3 Wansford Traffic Model. As documented in the Appraisal Specification Report (ASR) (HE551494-MMSJV-VTR-000-RP-TR-00008.PDF), analysis of the Wansford PCF Stage 2 base year west side of the Peterborough Traffic Model (WPTM), indicated that the model had not been calibrated or validated. In addition, the scope of the Wansford model was limited and as such not suitable for predicting re-routing of traffic and the interaction between local junctions and the major traffic attractor (Peterborough). Lastly, the size of the Stage 2 WPTM model did not allow any scope for any realistic Variable Demand Model (VDM) assessment for trip re-distribution or mode shift over a wider area.
2.1.2 Based on those assessments, the existing PCF Stage 2 WPTM model was enhanced to meet the PCF Stage 3 modelling objectives as shown in Figure 2-1. To achieve this, the SATURN simulation network was extended to provide a greater coverage to the south and west of the scheme. In addition, the south-east region traffic model (SERTM) network and demand was utilised to provide a fuller representation of strategic travel and a more realistic representation of longer distance trips. As outlined in section 2.2, to achieve a combined network the desired WPTM network was spliced into the SERTM buffer link structure.
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Figure 2-1: Wansford PCF 2-3 study areas
Source: Mott MacDonald Sweco Joint Venture. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
2.1.3 In addition to this, the SERTM demand was utilised instead of the existing PCF Stage 2 WPTM matrices to provide an up-to-date and robust demand starting point with suitable purpose disaggregation for VDM assessment. Details of how the SERTM model data was used in the PCF Stage 3 study, as well as the development of the VDM, are outlined in this chapter.
2.2 Model area and network
2.2.1 The base year for the Wansford traffic model is 2015. The network structure was enhanced to represent 2 distinct spatial areas as follows:
· Simulation area: this covers all areas where the schemes are likely to have an impact. Modelling within this area is characterised by representation of all trip movements, small zones and detailed network representation with junction modelling (including flow metering and blocking back). This area extends to where the schemes are likely to have the greatest impact. · Buffer area: this area is characterised by representation of all trip movements but from somewhat larger zones, less network detail with fixed speeds and
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no junction simulation. The buffer area covers most of England and is based on the SERTM network. To achieve the desired area of impact, the SATURN simulation network was expanded to provide greater coverage to the south and west of the A1, covering the A605 and A43 near to Corby and Duddington. This was necessary as the previous WPTM simulation network extent was limited around the scheme in those directions.
2.2.2 Additional network enhancement was provided to assist with the update of the base model. This included a review of all speed flow curves. As a result, some new speed flow curves were added to reflect the extended network within the simulation area. Zone centroid connectors were also revised; SATURN spigot links were used in the simulation area to connect the centroid connector onto stub links.
2.2.3 The use of the spliced SERTM network provided a fuller representation of strategic travel (in the buffer area) and a more realistic representation of longer distance trips. The study area showing the simulation area together with the buffer area within the area of impact is shown in Figure 2-2.
Figure 2-2: Wansford traffic model and the buffer area within the area of impact
Source: Mott MacDonald Sweco Joint Venture. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown
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copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
2.3 Modelled time periods
2.3.1 Three SATURN models are used to model representative weekday single hours which cover the most important periods of traffic flow. For all data sources, the following time periods have been used for the Wansford traffic model:
· AM peak hour: 07:30 – 08:30 · Inter-peak (IP) hour: 13:00 – 14:00 · PM peak hour: 16:30 – 17:30
2.4 User class segmentation
2.4.1 The Wansford traffic model uses 5 user classes that are consistent with the SERTM user classes:
· Car – employer’s business · Car – home based work · Car - other · Light goods vehicles (LGV) · Heavy goods vehicles (HGV)
2.5 Software used
2.5.1 The following software and their respective versions (in brackets) used for the A47 Wansford to Sutton modelling are as follows:
· SATURN (11.3.12W – Level N4 – MULTI-CORE) · DIADEM (version 5.0.9 64-bit)
2.5.2 SATURN is a suite of flexible network analysis programmes. SATURN is most widely used as a highway assignment modelling software package for the robust modelling of congested road networks due to its accurate representation of junction behaviour and the resulting delay.
2.5.3 DIADEM is a software tool. The purpose of DIADEM is to enable users to easily set-up variable demand models in accordance with the advice provided in TAG unit M2 variable demand modelling. The main demand model used in DIADEM is an incremental hierarchical logit model with the option of the following demand responses:
· Trip frequency · Time period choice
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· Mode choice · Destination choice / distribution
2.5.4 Travel times and other costs are provided by a traffic assignment model. DIADEM is principally used in conjunction with SATURN but the CONTRAM package may also be used.
2.6 Assignment procedure and generalised cost parameters
2.6.1 The route choice during a highway assignment is determined by the generalised travel cost incurred on each route. Generalised cost for a route between an Origin(O) and Destination (D) is a function of the travel time for a route and the distance travelled on the route plus any fares/tolls for the route, as shown in the equation below.
2.6.2 Generalised Cost = VOT*Time + VOC*Distance + Tolls, where:
VOT = values of time (pence per minute; PPM)
VOC = vehicle operating cost (pence per km; PPK)
2.6.3 The assignment utilises the Wardrop Equilibrium assignment algorithm which seeks to arrange traffic on congested networks such that the cost of travel on all routes used between each O-D pair is equal to the minimum cost of travel and all unused routes have equal or greater cost.
2.6.4 The generalised cost parameters (value of time and vehicle operating cost) used in the Stage 3 base model were derived from TAG data book, July 2017 release. The derived values are shown in Table 2-1 and Table 2-2 which are calculated in 2010 prices.
2.6.5 The Stage 3 base model and some of the initial forecasting work were commenced before December 2017 and therefore were developed based on TAG data book July 2017. However, it was agreed with Highways England that the latest version of May 2019 (at the time when this work is undertaking) should be used for the new forecast models.
Table 2-1: Value of time assumptions, pence per minute (PPM, 2010 prices, 2015 values)
Pence Per Minute (PPM) User class AM peak Inter-peak PM peak Car - employer’s business 29.81 30.54 30.24 Car - commuting 19.99 20.31 20.06 Car - other 13.79 14.69 15.58 LGV 21.07 21.07 21.07
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Pence Per Minute (PPM) User class AM peak Inter-peak PM peak HGV 49.19 49.19 49.19
Table 2-2: Vehicle operating cost assumptions, pence per kilometre (PPK, 2010 prices, 2015 values)
Pence per kilometre (PPK) User class AM peak Inter-peak PM peak Car - employer’s business 12.62 12.62 12.62 Car - commuting 6.25 6.25 6.25 Car - other 6.25 6.25 6.25 LGV 13.71 13.71 13.71 HGV 45.17 45.17 45.17
2.7 Model calibration and validation
2.7.1 Figure 2-3 below shows a high-level summary of the top line statistics for each modelled time period. These are displayed as a “spider” graph, where the area of the graph represents the total level of calibration / validation of the model. Analysis of these graphs confirms the above analysis, in that a high level of model calibration and validation performance has been achieved. Based on this assessment, it is considered that the model is fit for the purpose of assessing the A47 Wansford to Sutton dualling scheme. In summary, Table 2-3 shows that the following results have been achieved:
· Link calibration AM = 97%, IP = 96%, PM = 96% · Link validation AM = 100%, IP = 100%, PM = 90% · Turn calibration AM = 89%, IP = 90%, PM = 86% · Screenline calibration: AM = 83%, IP = 83%, PM = 100% · Screenline validation: AM = 100%, IP = 100%, PM = 100% · Journey time validation: AM = 83%, IP = 100%, PM = 83%
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Table 2-3: Summary of model calibration and validation
Criteria AM peak Inter-peak PM peak Link calibration (< GEH1 5) 97% 96% 96% Link validation (< GEH 5) 100% 100% 90% Turn calibration (< GEH 5) 89% 90% 86% Screenline calibration (< 5%) 83% 83% 100% Screenline validation (< 5%) 100% 100% 100% Journey time validation 83% 100% 83%
2.7.2 Overall, the A47 Wansford model has achieved a very high level of calibration across its count calibration and validation data. A similarly high level of calibration has been achieved with respect to the models screenline and journey time results. In addition to these metrics it should be noted that analysis of the Wansford A47 / A1 junction model shows that the calibration of all turns at this junction are within TAG guidance.
2.7.3 Despite mostly satisfying TAG criteria, in some cases in the AM or PM peak model results, it can be seen that the model is slightly below a pass rate of 85%. Further analysis of these results indicates that although the model may not pass the TAG criteria for all screenlines and journey times, the model passes if a slightly wider threshold is adopted, suggesting that the failure may be a result of the low (rural) screenline volumes making the TAG criteria harder to achieve.
1 The GEH (Geoffrey E. Havers) statistic based on a comparison of observed and modelled flow and is used 2 as an indicator of “goodness of fit”. The formula for the GEH statistic is ( ) ( . . ) √
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Figure 2-3: Top line summary statistics Top Line Summary Statstics - A47 Wansford to Sutton
AM Peak
No of Criteria % AM Calibration\ Validation Counts 97% Link GEH Cal Link Cal- Counts With GEH <5 238 97% 83% 99% JT Val Link DMRB Cal Link Cal- DMRB Flow Criteria 238 99% Link Val- Counts with GEH <5 10 100% 100% 100% Link Val- DMRB Flow Criteria 10 100% SL Val Link GEH Val Turn Cal- Counts With GEH <5 401 89% Turn Cal- DMRB Flow Criteria 401 96% 100% 83% Screen Line Cal- Flow Difference <5% 12 83% SL Cal Link DMRB Val Screen Line Val- Flow Difference <5% 4 100% 96% JT Routes- Time difference <15% or 1 min if greater12 83% Turn DMRB Cal Turn GEH Cal 89%
IP Peak
No of IP Calibration\ Validation Criteria % 96% Counts 100% Link GEH Cal 97% Link Cal- Counts With GEH <5 238 96% JT Val Link DMRB Cal Link Cal- DMRB Flow Criteria 238 97% Link Val- Counts with GEH <5 10 100% 100% 100% Link Val- DMRB Flow Criteria 10 100% SL Val Link GEH Val Turn Cal- Counts With GEH <5 401 90% Turn Cal- DMRB Flow Criteria 401 98% 83% 100% Screen Line Cal- Flow Difference <5% 12 83% SL Cal Link DMRB Val Screen Line Val- Flow Difference <5% 4 100% JT Routes- Time difference <15% or 1 min if greater12 100% 98% Turn DMRB Cal Turn GEH Cal 90%
PM Peak
No of PM Calibration\ Validation Criteria % 96% Counts Link GEH Cal Link Cal- Counts With GEH <5 238 96% 83% 96% JT Val Link DMRB Cal Link Cal- DMRB Flow Criteria 238 96% Link Val- Counts with GEH <5 10 90% 100% 90% Link Val- DMRB Flow Criteria 10 90% SL Val Link GEH Val Turn Cal- Counts With GEH <5 401 86% Turn Cal- DMRB Flow Criteria 401 93% 100% 90% Screen Line Cal- Flow Difference <5% 12 100% SL Cal Link DMRB Val Screen Line Val- Flow Difference <5% 4 100% JT Routes- Time difference <15% or 1 min if greater12 83% Turn DMRB Cal Turn GEH Cal 93% 86%
* Third column in the tables above shows % of links, turns, screenlines or journey time routes passing each criterion Source: SWECO
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2.8 Variable demand modelling
2.8.1 As the Stage 2 A47 Wansford modelling was not completed, no VDM was available at the inception of the Stage 3 study. Therefore, the Stage 3 VDM has been developed in its entirety during the Stage 3 study. Due to time constraints a proportionate approach was undertaken.
2.8.2 The VDM has been developed using DIADEM v6.3 software with the inclusion of applying fitting on factors (FOF) as part of SATNET before the main SATURN assignment procedure is called. The purpose of applying these FOFs is to adjust the DIADEM origin destination (OD) matrices split from production attraction (PA) input matrices to fit the calibrated base year matrices.
2.8.3 To support Road Investment Strategy (RIS) schemes such as these throughout the development process and especially for economic appraisal, it is required to use VDM in accordance with TAG unit M2. For PCF Stage 2, production attraction (PA) modelling was not specified in the VDM set up, which is not TAG compliant. For PCF Stage 3, home based PA and non-home based OD VDM will be developed with a DIADEM demand model with the following attributes:
· Segmentation by purpose: employers’ business / commute / other · Vehicle types: car / LGV / HGV · Home based (PA) / non-home based (OD) · Fixed no VDM: external to external home based work (HBW) movements / freight movements · Cost dampening for trips greater than 30 kilometres · Hierarchical incremental model · Model responses to frequency and distribution · Use of illustrative parameter values and adjustment using realism testing · Monitoring of demand model convergence to achieve TAG criteria
2.8.4 The cost damping curve was implemented during the realism testing. We retained the TAG / DIADEM guidance of capping the minimum trip length on which the cost damping takes effect to 30 kilometres. In order to calibrate the fuel cost elasticities, we looked at the sector-sector breakdown of the fuel cost elasticities based on internal (broadly the area of scheme impact) and external sectors (elsewhere). As the fuel cost elasticity in the external-external, and internal-external regions was significantly higher than the TAG recommendations, we incrementally changed the cost damping function until the elasticity was a similar order of magnitude to the internal-internal region.
2.9 Previous PCF Stage 0-2 traffic forecasting report
Wansford base year model
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2.9.1 For Stage 1, the existing Peterborough Traffic Model (PTM) developed by Peterborough City Council (PCC) has been cordoned around the west side of the PTM model (now called WPTM) to include the proposed scheme as shown in Figure 2-4.
Figure 2-4: Extent of the cordoned Wansford model for Stage 1
Source: SWECO. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
2.9.2 The original PTM was based on 2006 traffic data including roadside interview surveys (RSIs) collected in 2006 but later rebased to 2015. The validation of the 2015 rebased WPTM was never completed during Stage 2 due to the tight timescale of Stage 2 and as such, a Paramics model was developed during Stage 2 for forecasting and appraisal of the scheme for Stage 2.
Wansford Paramics model
2.9.3 As stated above, the WPTM was not fully completed on time due to the tight timescale of Stage 2, instead a Paramics model was used for the forecasting and the appraisal of the final stage 2 submission. The extent of the Paramics model is shown in
2.9.4 Figure 2-5 below.
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2.9.5 A summary of the Paramics model specification is shown in Table 2-4.
Figure 2-5: Wansford Paramics model (network defined in red)
Source: SWECO. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016. Table 2-4: Wansford Paramics model base year specifications for Stage 2 Category Comment Base year 2015 Time period AM / IP / PM peak hour
OD data year 2015 counts - OD estimated
Count data year Some data collection in 2015 Two User Classes: User classes · Car / LGVs · HGVs Consists of the A47 from west of Wansford to its bypass of Castor, Coverage and each of the roads connecting it the A1, Old North Road, and accesses from other intermediate junctions along the link. Convergence Not known
Variable Demand Model (VDM) No VDM was undertaken using the Paramics model.
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3. Forecasting approach
3.1.1 An overview of the approach taken to the forecasting of the scheme can be seen in Figure 3-1.
Figure 3-1: Flowchart of forecasting process
Source: SWECO
3.1.2 As discussed in the transport modelling package report (TMPR, HE551494- MMSJV-VTR-000-RP-TR-00016), dated April 2018, the base model for Stage 3 was an enhancement of the Stage 2 base highway assignment model. The opening year for the scheme in the forecast model is now 2025 and the scheme design year is 2040.
3.1.3 The traffic forecasts account for future proposals for residential and employment developments in the local area as well as corresponding transport network changes. The forecast scenarios comprise of the following:
· A set of transport network changes
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· Assumptions about changes in values of time and vehicle operating costs over time · A specific set of development assumptions · Application of the National Trip End Model (NTEM) growth factors extracted from TEMPRO 7.2 as a constraint on trip growth for cars and public transport (PT) · Application of growth of freight traffic from the Department for Transport (DfT) road traffic forecasts (RTF2018) · Variable demand modelling (VDM) was undertaken using dynamic integrated assignment and demand modelling (DIADEM Version 6.3). Demand model parameters were derived from realism tests on the refined Stage 3 base model. Details of the VDM process are reported in section 7 of this report.
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4. Uncertainty log and forecast years
4.1 Introduction
4.1.1 In line with TAG unit M4, forecasting and uncertainty, an uncertainty log has been developed. The purpose of the uncertainty log is to record the central forecasting assumptions that underpin the core scenario and record the degree of uncertainty around these central assumptions. These assumptions will be the basis for developing a set of alternative scenarios.
4.1.2 The uncertainty log deals with local uncertainty about future land use (demand side uncertainty) and transport schemes (supply side uncertainty), which will affect the transport network. The uncertainty relates to the likelihood of a given scheme or development taking place, as well as the nature and size of the development.
4.2 Forecasting at PCF Stage 0-2
4.2.1 It was confirmed that for Stage 2 that no uncertainty log was available for Wansford. However, Skanska, the transport consultant for Peterborough City Council (PCC), provided a spreadsheet detailing the developments assumptions included in the Peterborough Transport Model (PTM), although no classification on the certainty of these developments is included in the assessment.
4.3 Forecasting at PCF Stage 3
4.3.1 For Stage 3, following discussions with Skanska and Peterborough City Council, clarification was provided on which committed and allocated sites should be included in the “core” scenario assumptions. In the Skanska spreadsheet, the non-committed developments are factored down from the 2036 assumptions to create intermediate years between 2015 and 2036. It was agreed with PCC that no further development should be assumed for the period 2036-2037. Following discussion with Highways England, it has been assumed that this proportioning approach will be suitable for the PCF Stage 3 modelling. The development proportion approach factors derived from the Skanska modelling are shown in Appendix D.
4.4 Forecast years
4.4.1 After consultation with Highways England, it is envisaged that the estimated of completion of construction for the A47 Wansford scheme will be between 2023 and 2025 according to Highways England’s latest delivery plan (2019-2020). Therefore, it has been agreed with Highways England to change the model forecast years from 2022 and 2037 to 2025 (opening year) and 2040 (design
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year) and the new forecast year demand matrices will be derived by applying TEMPro background growth factors (2022 to 2025 and 2037 to 2040) to original forecast year reference demand matrices. This assumption is fully explained in the technical note – A47 RIS Scheme Opening Years – Update (HE551490-GTY- VTR-000-RP-TR-30002).
4.5 Uncertainty log (local area plan data and transport supply data)
4.5.1 The uncertainty log contains the local authority network schemes and Highways England schemes in regions nearby and significant to the model and forecasts for the scheme.
4.5.2 As per TAG, the schemes included in the Do Minimum (DM) scenarios have a likelihood of at least ‘near certain’ or ‘more than likely’. Table 4-1 provides the TAG definitions of the uncertainty log classifications.
Table 4-1: Classification of future impacts
Probability of the Local authority / development scheme Highways England input Near certain: The · Intent announced by proponent to Stage 4 completed, scheme outcome will happen regulatory agencies entering or in Stage 5 (such as or there is a high · Approved development proposals scheme consented). probability that it will · Projects under construction happen
More than likely: · Submission of planning or consent Stage 2 completed, scheme The outcome is application imminent entering or in Stage 3 (such as likely to happen but · Development application within the consent preferred route announced). there is some process uncertainty · Projects under construction Reasonably · Identified within a development plan Scheme in Stage 1 or 2 (such foreseeable: The · Not directly associated with the transport as option selection. outcome may strategy / scheme, but may occur if the happen, but there is strategy / scheme is implemented significant · Development conditional upon the transport uncertainty strategy / scheme proceeding · A committed policy goal, subject to tests (for example, of deliverability) whose outcomes are subject to significant uncertainty Hypothetical: There · Conjecture based upon currently available Scheme in Stage 0 (such as is considerable information major road project initiated). uncertainty whether · Discussed on a conceptual basis the outcome will · One of a number of possible inputs in an ever happen initial consultation process · Or a policy aspiration
4.5.3 It was confirmed by Amey that no uncertainty log was available for the west Peterborough Traffic Model (WPTM) Stage 2 works. As a substitute, a
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spreadsheet was provided by Skanska that detailed the developments assumed in the PTM model. However, no classification on the certainty of these developments is included in the assessment. However, as these developments have been adopted in the PTM forecasting they have been assumed to be “core” scenario assumptions
4.5.4 The non-committed developments reported by Skanska were factored down from the 2036 assumptions to create interim years between 2015 and 2037. This interpolating approach has been adopted for the PCF Stage 3 modelling.
4.5.5 The area covered by the Skanska uncertainty log covers the entire PCC area and has informed by their local plan for the period 2016 to 2036. Within the plan is a commitment to deliver housing and other mixed-use development over the 20- year period and PCC has identified 6 large-scale development sites on their urban fringe to support this objective as shown in Figure 4-1.
4.5.6 Following further consultation with PCC, they confirmed that no major changes were made to the planning data and hence it was still appropriate to use the uncertainty log as prepared during the MMSJV work in 2018.
Figure 4-1: Major development sites identified in Peterborough local plan
Source: SWECO. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
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4.5.7 The major development sites shown above are summarised as follows:
· Great Haddon: an area bounded by the A1(M) and A15 to the south-west of the city · Hampton: an area adjoining the existing suburb of Hampton Hargate to the south of the city · Stanground South: an area near the A605 road to the south-east of the city · Norwood: an area bounded by the A47 and A16 to the north-east of the city · Paston Reserve: an area adjoining the Norwood development to the north-east of the city · Land north of Ailsworth and Castor: an area on the A47 to the west of the city
4.5.8 Hampton, Paston Reserve and Stanground South are fully committed in the local plan. The remaining 3 developments have land set aside but are not at this time fully committed.
4.5.9 In addition to developments, other nearby changes to the transport network such as highway improvements or new public transport infrastructure may result in changes to local traffic demand. The primary highway infrastructure project in the vicinity of Peterborough is a road investment strategy (RIS) junction improvement scheme at Guyhirn approximately 20 kilometres east of the city centre. The Guyhirn scheme is being progressed through the same framework as this one, but is unlikely to transmit significant benefits across to the west of the city.
4.6 Modelled scenarios
4.6.1 For forecasting purposes, transport networks representing the supply and cost of transport in future years were required as a basis to assess the impact of the proposed scheme. Future year transport supply and costs relate to changes in the transport networks, for example new transport infrastructure.
4.6.2 Highway networks have been produced for 2 forecast scenarios:
· Do Minimum (base + committed schemes) · Do Something (base + committed schemes + Wansford option 2)
4.6.3 These have all been created for 2 forecasting years:
· 2025 – opening year · 2040 – design year
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5. Reference forecast demand
5.1 Overview
5.1.1 This chapter summarises the approach adopted to produce reference forecast demand for use in the original future year forecasts of 2025 and 2040. Traffic generated by planned specific developments has been included in the forecast demand, which has been constrained to forecast National Trip End Model (NTEM) levels of growth at balancing area level.
5.1.2 This section describes how the developments that are planned in the future years of 2025 and 2040 have been taken into account and how the predicted generations / attractions from / to the developments have been included into the future traffic models. The data required to undertake this task can be summarised as follows:
· Uncertainty log information from Skanska (agreed with Peterborough City Council) · Trip rates derived from NTEM v7.2 for cars · Trip rates derived from TRICs for LGVs and HGVs
5.1.3 All developments, provided by Skanska, within the west Peterborough traffic model (WPTM) study area are included in the uncertainty log as shown in Figure 5-1. It should be noted, due to the network extension some of the WPTM network is outside of the catchment area for the PTM model (such as the Peterborough region). It is assumed for this area TEMPRO growth factors will be applied.
5.1.4 The uncertainty log entries which correspond to Figure 5-1 are shown in Appendix D. All the developments which were based on TAG likelihood classification of at least ‘near certain’ or ‘more than likely’, designated as “core” scenario by Skanska have been included in the uncertainty log.
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Figure 5-1: A47 Wansford Stage 3 development locations in Peterborough
Source: SWECO. This map is based upon Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways England 100030649 2016.
5.2 NTEM growth of car trips
5.2.1 Forecast trip ends from version 7.2 of the NTEM were used to derive trip end growth factors at model zone level, via an NTEM to model zone correspondence list.
5.2.2 The growth factors are derived as origin and destination factors (or production and attraction factors for home based trips) for each of the demand segments required for input into the variable demand model.
5.2.3 Growth factors have been derived for car vehicle trips for the 2015 base year and the 2 forecast years (2025 and 2040). Growth factors have been derived for car trips between the 2015 base year and the 2 forecast years (2025 and 2040).
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5.3 NTEM growth of goods vehicles
5.3.1 Freight growth factors have been extracted from road traffic forecasts (RTF) 2018 scenario 1 as shown in Table 5-1.
Table 5-1: RTF18 goods vehicle growth rates from 2018
LGV HGV
Region 2025 2040 2025 2040
East Midlands 1.164 1.399 0.989 1.019 Eastern England 1.149 1.378 1.031 1.117 Rest of UK (GB) 1.160 1.393 1.002 1.050
5.4 Trip generation and distribution for modelled developments
5.4.1 Car trips ends were generated from the identified development schemes based on trip rates derived from NTEM v7.2 using the ‘alternative forecasting assumptions’ available within the TEMPRO software. The procedures allow, for each of the areas identified, the manual introduction of a number of households, jobs (for instance 1,000) and the calculation of a trip rate per house / job by dividing the expected NTEM v7.2 output number of trips by 1,000. This approach has been adopted using the 2015 year for:
· Each home-based and non-home trip purpose modelled · An average 24 hours weekday (production / attraction home based trip purposes, that is, employers’ business, commute, other) · Each peak period for the origin destination trip purposes (specifically AM, Inter-peak (IP), PM and Off-peak (OP) for non-home based employer’s business and non-home based other)
5.4.2 Appendix G shows the car NTEM v7.2 trip rates for the year of 2015, for each purpose, for each period and for each area where the planned developments are located. These trip rates were then applied to the quantum (housing, number of jobs) in each development for each forecast year.
5.4.3 For the majority of the employment developments listed in the uncertainty log the amount of floorspace available was provided (rather than the number of jobs as per units of the NTEM v7.2 tip rate). Therefore, a conversion between square metres of floorspace to number of jobs was applied for each of the land uses of A1 (retail), B1b (R&D Space), B2 (industrial and manufacturing), B8 (storage and distribution) and mixed B class. Table 5-2 shows the number of jobs per 100sqm of (gross floor area) GFA for the different floorspace usage. The methodology has applied the guidance outlined in the home and community’s agency employment density guide (2015).
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Table 5-2: Jobs per 100 sqm of GFA
Jobs per 100 sqm of GFA (NIA – Net User Class Internal Area) A1 (Retail) 6.66 B1 (General offices) 10.07
B2 (Industrial and manufacturing) 3.03 B8 (Storage and distribution) 1.45
5.4.4 The proposed employment sites were also expected to generate LGV and HGV trips. For the purpose of calculating trip ends generated by these, NTEM v7.2 trip rates are shown in Appendix G could not be used as they refer to car only. Therefore, TRICs trip rates were used instead.
5.4.5 Average TRICs trip rate per employee were extracted from the software for each of the modelled time periods for the A1, B1, B2 & B8 categories taking into account only those sub-categories likely to be relevant for the developments considered. Table 5-3 to Table 5-6 show the average TRICs trip rates per employee by vehicle type applied to the number of jobs specified or calculated for each of the development employment sites.
Table 5-3: Average TRICs trip rates - A1
LGV HGV Trip rate / employee Arrivals Departures Arrivals Departures AM 07:00-10:00 0.211 0.205 0.011 0.007 IP 10:00-16:00 0.181 0.168 0.009 0.009 PM 16:00-19:00 0.152 0.173 0.005 0.009 OP 19:00-07:00 0.024 0.027 0.001 0.001
Table 5-4: Average TRICs trip rates - B1
LGV HGV Trip rate / employee Arrivals Departures Arrivals Departures AM 07:00-10:00 0.009 0.012 0.001 0.001 IP 10:00-16:00 0.009 0.009 0.001 0.001
PM 16:00-19:00 0.007 0.005 0.001 0.001 OP 19:00-07:00 0 0 0 0
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Table 5-5: Average TRICs trip rates – B2
LGV HGV Trip rate / employee Arrivals Departures Arrivals Departures AM 07:00-10:00 0.044 0.052 0.013 0.013
IP 10:00-16:00 0.043 0.043 0.012 0.013 PM 16:00-19:00 0.032 0022 0.010 0.007
Table 5-6: Average TRICs trip rates - B8
LGV HGV Trip rate / employee Arrivals Departures Arrivals Departures AM 07:00-10:00 0.007 0.005 0.092 0.093 IP 10:00-16:00 0.008 0.007 0.071 0.083 PM 16:00-19:00 0.004 0.006 0.086 0.088 OP 19:00-07:00 0.001 0.001 0.018 0.014
5.4.6 The calculated trip ends obtained by applying the NTEM v7.2 and the TRICs trip rates were then distributed using the base demand trip distribution through a SATURN furness process to output a set of development matrices for both 2022 and 2037. This was done for each modelled period (24 hours for the home based trips) and average period (AM, IP, PM and OP) for the non-home based trips as well as for each mode (Cars / LGVs / HGVs).
5.4.7 The methodology for distributing future development trip ends using the base demand matrices required the base demand at zone level, where the development has been allocated to be populated with some trips in the base year. For the vast majority of the developments the existing model zones had associated trips which could be used. In rare occurrences were the base zone was empty, a zone with a similar trip distribution was chosen to distribute the development trips. The same approach has been adopted when development trips for a time period were missing in the base year matrices, and in that case a distribution taken from a nearby similar zone was used.
5.5 Dependent development
5.5.1 At the time of writing this report, no dependent developments have been identified. The forecast modelling assessment does however examine the impact of the explicitly modelled developments identified in the uncertainty log, to identify any potential traffic impacts in both the Do Minimum (DM) and Do Something (DS) scenarios.
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5.6 Constraining to district level
5.6.1 The derivation of the 2025 and 2040 reference demand matrices was carried out by using TEMPRO trip end calculations and SATURN’s MX Furness procedure with a spreadsheet interface. This process allows for the forecast demand to be constrained at “balancing areas”, which are user-defined collections of NTEM zones, potentially representing counties, regions or districts. The balancing areas defined in this analysis are listed in Table 5-7.
5.6.2 A Furness process was then carried out to constrain the growth to NTEM, which in general consists of the following steps:
· Apply alternative assumptions facility within TEMPRO to exclude explicitly modelled development growth · Apply growth factors to base demand to create target trip end · Furness base demand to forecast target trip ends · Add in development demand Table 5-7: Balancing Area Descriptions
Balancing Area Description 1 Peterborough 2 East England 3 East Midlands 4 Great Britain
5.7 Combined background and development trip matrices
5.7.1 Using TEMPro alternative development assumptions feature target trip ends were reduced, according to the forecasted household and job growth for each development. Explicitly modelled development demand is then added in addition to the balanced NTEM growth. This ensured that the balancing area target growth for NTEM zones are maintained. Overall growth between the base year and the future year reference demand are reported in Table 5-8and Table 5-10 below.
Table 5-8: Highway Reference Demand at OD Level – Core Scenario AM Peak
2025 2040 Purpose Base Ref Growth% Base Ref Growth% EB 477,588 515,526 7.9% 477,588 559,757 17.2% Commute 2,113,219 2,248,033 6.4% 2,113,219 2,431,067 15.0% Other 2,023,900 2,245,896 11.0% 2,023,900 2,523,148 24.7% LGV 533,801 618,581 15.9% 533,801 743,094 39.2%
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2025 2040 Purpose Base Ref Growth% Base Ref Growth% HGV 217,914 218,777 0.4% 217,914 229,891 5.5% Total 5,366,423 5,846,814 9.0% 5,366,423 6,486,957 20.9%
Table 5-9: Highway Reference Demand at OD Level – Core Scenario Inter Peak
2025 2040 Purpose Base Ref Growth% Base Ref Growth% EB 412,213 440,972 7.0% 412,213 478,236 16.0% Commute 728,865 769,440 5.6% 728,865 826,838 13.4% Other 2,863,263 3,151,454 10.1% 2,863,263 3,537,068 23.5% LGV 513,250 594,843 15.9% 513,250 714,601 39.2% HGV 209,357 210,149 0.4% 209,357 220,780 5.5% Total 4,726,948 5,166,858 9.3% 4,726,948 5,777,522 22.2%
Table 5-10: Highway Reference Demand at OD Level – Core Scenario PM Peak
2025 2040 Purpose Base Ref Growth% Base Ref Growth% EB 499,349 542,862 8.7% 499,349 589,507 18.1% Commute 1,983,961 2,098,762 5.8% 1,983,961 2,258,020 13.8% Other 2,913,228 3,215,664 10.4% 2,913,228 3,607,647 23.8% LGV 426,016 493,629 15.9% 426,016 592,970 39.2% HGV 138,216 138,772 0.4% 138,216 145,832 5.5% Total 5,960,769 6,489,689 8.9% 5,960,769 7,193,976 20.7%
5.8 Alternative scenarios
5.8.1 An optimistic alternative scenario test, which includes additional highway and land use developments which have not been included in the core scenario, will not be conducted. Additional sensitivity tests will be undertaken for the high and low scenarios to inform the economic assessment. Table 5-11 below details the assumptions applied to the core, high and low scenarios.
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Table 5-11: Core, low and high scenario definitions
National Trip End Model Scenario Supply Demand (NTEM) constraint Near certain and more than likely Near certain and more than Core Standard NTEM schemes likely developments Near certain, more than likely Near certain, more than High growth High growth NTEM schemes likely developments Near certain and more than likely Near certain and more than Low growth Low growth NTEM schemes likely developments
5.8.2 Based on TAG guidance, high and low growth scenarios will be developed in which the core demand will be amended by a proportion of the base year demand using the formula:
=
· u is the uncertainty, the proportion ∙of base− year demand to be added to (in the high growth scenario) or subtracted from (in the low growth scenario) the core forecast demand · p is a factor representing the uncertainty in macroeconomic variables influencing travel demand, defined in TAG unit M4 “forecasting and uncertainty” as 2.5% for national highway traffic · f is the forecast year being modelled (up to a maximum of 36 years after the base model) · b is the model base year
5.8.3 The derivation of u for the forecast models is therefore:
= 2.5% × 2025 2015 = 7.91% =2.5%× 2040 2015 = 12.50%