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Camborne Pool RedruthTransport Package

Assignment Model Validation Report

August 2011Cornwall Council


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P:\Southampton\ITW\Projects\291073 cpr 2011\wp\CPR BFFB LMVR noFig AppAD RevB comp doc

12 August 2011

Camborne Pool Redruth Transport Package

Assignment Model Validation Report

August 2011

Cornwall Council

Mott MacDonald, Stoneham Place, Stoneham Lane, Southampton SO50 9NW, United Kingdom T +44(0) 23 8062 8800 F +44(0) 23 8062 8801, W www.mottmac.com

A3 Carrick House, Pydar Street, Truro, TR1 1EB



Mott MacDonald, Stoneham Place, Stoneham Lane, Southampton SO50 9NW, United Kingdom T +44(0) 23 8062 8800 F +44(0) 23 8062 8801, W www.mottmac.com

Revision Date Originator Checker Approver Description

A June 2011 GS NG IJ First Draft

B August 2011 GS IJ IJ Final

Issue and revision record

This document 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.

We accept 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 us and from the party which commissioned it.


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Chapter Title Page

1. Introduction 11.1 Background ________________________________________________________________________ 11.2 Project Location _____________________________________________________________________ 11.3 Purpose of this Report ________________________________________________________________ 1

2. 2005 Highway Model Description 42.1 Introduction ________________________________________________________________________ 42.2 Network Description__________________________________________________________________ 42.3 Zoning System ______________________________________________________________________ 4

3. 2005 Trip Matrix Building 73.1 Introduction ________________________________________________________________________ 73.2 Matrix Estimation ___________________________________________________________________ 10

4. 2005 Base Year Assignment 15

5. 2005 SATURN Model Calibration and Validation 165.1 Introduction _______________________________________________________________________ 165.2 Validation Criteria___________________________________________________________________ 165.3 Calibration Results__________________________________________________________________ 165.4 Flow Validation_____________________________________________________________________ 175.5 Journey Time Validation _____________________________________________________________ 31

6. 2005 Public Transport Model 346.1 Model Network _____________________________________________________________________ 346.2 Matrices __________________________________________________________________________ 366.2.1 Rail Trip matrices ___________________________________________________________________ 366.2.2 Rail Fares matrices _________________________________________________________________ 386.2.3 Bus Trip Matrices ___________________________________________________________________ 386.3 Public Transport Assignment __________________________________________________________ 396.4 Rail validation______________________________________________________________________ 396.5 Bus validation______________________________________________________________________ 39

7. 2010 Highway Model Update 417.1 Introduction _______________________________________________________________________ 417.2 Updated Highway Model Network ______________________________________________________ 417.3 Updated Trip Matrices _______________________________________________________________ 437.3.1 Introduction _______________________________________________________________________ 437.3.2 Car Matrices_______________________________________________________________________ 447.3.3 Goods Vehicle Matrices ______________________________________________________________ 467.4 Traffic Data________________________________________________________________________ 477.5 2010 Traffic Model Assignment ________________________________________________________ 477.6 2010 Calibration and Validation Results _________________________________________________ 487.6.1 Calibration and Validation Locations ____________________________________________________ 487.6.2 Validation Criteria___________________________________________________________________ 51

Content



7.6.3 Calibration Results__________________________________________________________________ 517.6.4 AM Peak Validation Results___________________________________________________________ 647.7 Interpeak Validation Results __________________________________________________________ 677.8 PM Peak Validation Results___________________________________________________________ 70

8. 2010 Public Transport Model Update 748.1 Network Update ____________________________________________________________________ 748.2 Matrix Update______________________________________________________________________ 748.3 Model Validation____________________________________________________________________ 74

9. Conclusions 75

Appendices 76Appendix A. Model Zoning System _______________________________________________________________ 77Appendix B. Roadside Interview Matrix Building Methodology __________________________________________ 80Appendix C. Comparison of 2005 prior and final matrices by sector ______________________________________ 84Appendix D. Detailed 2005 Model Validation Results _________________________________________________ 88Appendix E. Journey Time Validation Results 2005 _________________________________________________ 106Appendix F. Matrix Estimation 2010 Base – Sector Analysis __________________________________________ 121F.1. AM Peak_________________________________________________________________________ 121F.2. Interpeak ________________________________________________________________________ 122F.3. PM Peak_________________________________________________________________________ 123 Tables Table 3-1: Percentage of Traffic Interviewed at each RSI Site ____________________________________________ 7Table 3-2: AM RSI Matrices by Journey Purposes _____________________________________________________ 9Table 3-3: Interpeak RSI Matrices by Journey Purposes ________________________________________________ 9Table 3-4: PM RSI Matrices by Journey Purposes _____________________________________________________ 9Table 3-5: Final observed data purpose split ________________________________________________________ 10Table 4-1: Generalised Cost Coefficients ___________________________________________________________ 15Table 4-2: Convergence Criteria __________________________________________________________________ 15Table 4-3: Achieved Convergence ________________________________________________________________ 15Table 5-1: Assignment Validation - Acceptability Guidelines ____________________________________________ 16Table 5-2: Flow Calibration Results (Counts used for Matrix Estimation) ___________________________________ 17Table 5-3: Flow Validation Results (Validation Counts) ________________________________________________ 17Table 5-4: East Hill AM Peak Validation ____________________________________________________________ 18Table 5-5: East Hill Interpeak Peak Validation _______________________________________________________ 18Table 5-6: East Hill PM Peak Validation ____________________________________________________________ 19Table 5.7: AM Peak Light Vehicle Screenlines _______________________________________________________ 25Table 5.8: AM Peak Heavy Vehicle Screenlines ______________________________________________________ 26Table 5.9: Interpeak Light Vehicle Screenlines _______________________________________________________ 27Table 5.10: Interpeak Heavy Vehicle Screenlines_____________________________________________________ 28Table 5.11: PM Peak Light Vehicle Screenlines ______________________________________________________ 29Table 5.12: PM Peak Heavy Vehicle Screenlines _____________________________________________________ 30Table 5-13: Journey Time Survey Accuracy _________________________________________________________ 31Table 5-14: AM Peak Journey Time Validation Results ________________________________________________ 32Table 5-15: Interpeak Journey Time Validation Results ________________________________________________ 32Table 5-16: PM Peak Journey Time Validation Results ________________________________________________ 32



Table 6-1: Summary of Bus Routes _______________________________________________________________ 34Table 6-2: Ticket Group by Journey Purpose – assumed spilts __________________________________________ 36Table 6-3: Weekday and Weekend Spilt by Journey Purpose ___________________________________________ 36Table 6-4: Assumed Journey Purpose splits by Time of Travel – Cornwall only _____________________________ 37Table 6-5: Assumed Journey Purpose Splits by Time of Travel – Rest of UK _______________________________ 37Table 6-6: Split of Trips by Time Period and Journey Purpose___________________________________________ 38Table 6-7: Bus Passengers Validation Results _______________________________________________________ 39Table 7.1: Light Vehicle Proportions _____________________________________________________________ 43Table 7.2: Housing Completions 2006 to 2010_____________________________________________________ 44Table 7.3: Commercial Completions 2006 to 2010__________________________________________________ 45Table 7.4: Trip Rates_________________________________________________________________________ 46Table 7.5: Car Matrix Growth __________________________________________________________________ 46Table 7.6: Goods Vehicle Factors_______________________________________________________________ 46Table 7.7: East Hill Observed Data Adjustment Factors______________________________________________ 47Table 7.8: Generalised Cost Coefficients _________________________________________________________ 47Table 7.9: Convergence Parameters ____________________________________________________________ 48Table 7.10: Achieved Convergence ______________________________________________________________ 48Table 7.11: Assignment Validation - Acceptability Guidelines __________________________________________ 51Table 7.12: AM Peak Pre-Matrix Estimation Results _________________________________________________ 52Table 7.13: Interpeak Pre-Matrix Estimation Results _________________________________________________ 53Table 7.14: PM Peak Pre-Matrix Estimation Results _________________________________________________ 54Table 7.15: AM Peak Calibration Results __________________________________________________________ 58Table 7.16: Interpeak Calibration Results__________________________________________________________ 59Table 7.17: PM Peak Calibration Results __________________________________________________________ 60Table 7.18: AM Peak East Hill Turning Movement Results ____________________________________________ 61Table 7.19: Interpeak East Hill Turning Movement Results ____________________________________________ 62Table 7.20: PM Peak East Hill Turning Movement Results ____________________________________________ 63Table 7.21: AM Peak Flow Validation – Light Vehicles________________________________________________ 64Table 7.22: AM Peak HGV Validation_____________________________________________________________ 64Table 7.23: AM Journey Time Results ____________________________________________________________ 65Table 7.24: Interpeak Flow Validation – Light Vehicles _______________________________________________ 67Table 7.25: Interpeak HGV Validation ____________________________________________________________ 67Table 7.26: Interpeak Journey Time Results _______________________________________________________ 67Table 7.27: PM Peak Flow Validation _____________________________________________________________ 70Table 7.28: PM Peak HGV Validation_____________________________________________________________ 70Table 7.29: PM Peak Journey Time Results________________________________________________________ 71

Figures Figure 1.1: Study Area _________________________________________________________________________ 2Figure 2.1: 2005 Highway Network _______________________________________________________________ 5Figure 2.2: Average Weekday Flow at Wesley Street, June 2005________________________________________ 6Figure 2.3: Local Monthly Profile _________________________________________________________________ 6Figure 3.1: RSI Locations_______________________________________________________________________ 8Figure 3-2: Traffic Count Locations ________________________________________________________________ 11Figure 3-3: AM Peak Trip Length Distribution Proportions ______________________________________________ 12Figure 3-4: Interpeak Trip Length Distribution Proportions ______________________________________________ 12Figure 3-5: PM Peak Trip Length Distribution Proportions ______________________________________________ 13



Figure 3-6: AM Peak Trip Length Distribution Trip Numbers_____________________________________________ 13Figure 3-7: Interpeak Trip Length Distribution Trip Numbers ____________________________________________ 14Figure 3-8: PM Peak Trip Length Distribution Trip Numbers_____________________________________________ 14Figure 5-1: AM Peak Network Flows _______________________________________________________________ 20Figure 5-2: Interpeak Network Flows_______________________________________________________________ 21Figure 5-3: PM Peak Network Flows _______________________________________________________________ 22Figure 5-4: Screenlines _________________________________________________________________________ 24Figure 5-5: Journey Time Survey Routes ___________________________________________________________ 33Figure 6-1: Local Bus Routes ____________________________________________________________________ 35Figure 7.1: Highway Network ___________________________________________________________________ 42Figure 7.2: Count Locations 2010 _______________________________________________________________ 49Figure 7.3: Journey Time Routes 2010 ___________________________________________________________ 50Figure 7.4: AM Peak Trip Length Distribution Proportions_____________________________________________ 55Figure 7.5: Interpeak Trip Length Distribution Proportions ____________________________________________ 56Figure 7.6: PM Peak Trip Length Distribution Proportions_____________________________________________ 57Figure 7.7: AM Peak Journey Time Validation______________________________________________________ 65Figure 7.8: Interpeak Journey Time Validation _____________________________________________________ 68Figure 7.9: PM Peak Journey Time Validation______________________________________________________ 71Figure 7.10: 2010 AADT Flows (in vehicles)________________________________________________________ 73


1


1.1 Background

In February 2011, the Camborne Pool Redruth Transport Package was promoted to the Development Pool following a successful Expression of Interest in January 2011. A Best and Final Funding Bid (BAFFB) will be submitted to the Department for Transport (DfT) by 09 September 2011.

The project received programme entry in 2008. Funding is now being sought for a project with a reduced scope, and the traffic and economic assessments are being updated to meet the requirements of Value for Money Guidance issued by the DfT in May 2011.

This report describes the development and validation of a transport model which represents travel in the Camborne Pool Redruth area. A separate Existing Data & Traffic Survey Report describes the data used to develop the model, including roadside interview data, traffic counts and journey time surveys.

Separate highway model and public transport models have been developed using SATURN and VISUM software respectively, for am peak, inter-peak and pm peak hours. The models were originally built for a 2005 base year, but have now been updated to 2010 to take account of network and land use changes since 2005.

1.2 Project Location

Camborne, Pool and Redruth taken together form a continuous corridor of urban development for over five miles along the inland western spine of Cornwall. The towns are located on the A30, A3047 and the London – Penzance railway line (see Figure 1.1). The A30 trunk road is one of the three road corridors that link Cornwall to the rest of the UK.

1.3 Purpose of this Report

This Assignment Model Validation Report outlines the methodology used to build and validate the base year highway and public transport models in 2005, and the updates to a 2010 base year.

The report concludes that the updated 2010 model provides a good basis for updated traffic forecasts and economic assessments for the project.

1. Introduction

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2.1 Introduction

Halcrow had been appointed in 2005 to develop the Camborne Pool Redruth (CPR) base year highway networks and build trip matrices using the results of six roadside interview surveys. Once these were complete Mott MacDonald (MM) carried out the highway model validation. The validated model was used for analysing the CPR Transport Strategy for inclusion in the Major Scheme Business Case (MSBC).

2.2 Network Description

The network set up in 2005 covered all the routes between Camborne and Redruth with connection to the rest of the country via A30. The majority of the local roads in the urban area were also included. Traffic models were developed for the AM peak hour of 0800-0900, a typical interpeak hour of 1100-1200 and the PM peak hour of 1700-1800 within June 2005. Figure 2.1 shows the extent of the highway network model.

Analysis of the average weekday vehicle flow in June 2005 from the Automatic Traffic Counter on Wesley Street, Camborne (see Figure 2.2) shows that the am and pm peak hours are 0800-0900 and 1700-1800. The flow levels during 1100-1200 are typical of an interpeak hour. No other permanent data were available within the urban area of Camborne Pool and Redruth. Counters were situated on the A30 but these represented longer distance traffic patterns as opposed to the more local trips within Camborne, Pool and Redruth.

Figure 2.3 compares the 12 hour weekday flow profile from the A30 counters and the Wesley Street counter throughout 2005. The A30 profiles show that flows rise from January reaching a peak in August and then falling to December. June flow on the A30 is some 9% higher than the annual average 12hour weekday flow. The profile for Wesley Street is much flatter with much lower flows in August and January. June flow on Wesley Street is only 4% higher than the annual average 12hour weekday flow. Comparing June flow on Wesley Street to the other neutral months of the year shows that June flow is just 2% higher than a neutral month average. This confirms that June is a suitable base for the model.

2.3 Zoning System

The zoning system provided by Halcrow has 182 zones with zone 181 covering Truro and the rest of the country. Analysis of census data for journeys to work and rail trips within Cornwall revealed that Truro and St Austell were significant origins and destinations for traffic within Camborne, Pool and Redruth. Therefore two additional zones, number 183 and 184, were created to represent Truro and St Austell, with zone 181 left to cover the rest of eastern Cornwall and the rest of the UK. Appendix A contains figures showing the zoning system.

2. 2005 Highway Model Description

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Figure 2.2: Average Weekday Flow at Wesley Street, June 2005

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west of Camborne WBCamborne-Pool EBCamborne-Pool WBPool-Redruth EBPool-Redruth WBRedruth to A390 EBRedruth to A390 WBWesley Street 2-way



7

3. 2005 Trip Matrix Building 3.1 Introduction

Roadside Interview Surveys (RSI’s) had been carried out at four internal sites around the East Hill junction in March 2003 and at two outer sites in June 2005. (Figure 3.1) shows the location of each RSI site. The six sites included are:

� Site A: Pendarves Road Eastbound

� Site B1: A3047 (Dual Carriageway) Southbound

� Site B2: Blowinghouse Hill Westbound

� Site C: Tolvaddon Road Southbound

� Site 1: A3047 Church Street Eastbound

� Site 2: A393 Lanner Hill Southbound

Table 3.1 shows the percentage of traffic interviewed at each RSI sites for each time period.

Table 3-1: Percentage of Traffic Interviewed at each RSI Site RSI Sites AM (8-9) IP (11-12) PM (17-18)

A 11% 25% 20%

B1 14% 30% 16%

B2 56% 26% 40%

C 27% 32% 35%

1 19% 25% 27%

2 42% 41% 32%

Halcrow prepared trip matrices using the RSI data and produced matrices for the am peak, interpeak and pm peak. The matrices were split by vehicle type into light vehicles which included cars and light goods vehicles (lgvs), and heavy vehicles which included ogv1 and ogv2. The matrices were also spilt into 6 different trip purpose types – education trips, employers business, commuting, non-home based trips, shopping trips and other trips. Appendix B is the Halcrow technical note describing the matrix building methodology and explaining how expansion factors were calculated.

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Once MM received the final RSI matrices, some of the trip purposes were combined to give four final user classes, namely

� Light vehicles commuting

� Light vehicles employment business

� Light vehicles other trips

� Heavy vehicles

Tables 3.2 to 3.4 show the split by journey purpose for each RSI site in each time period. This includes the effect of removing any trips that would have been observed at two or more of the RSI sites. The analysis shows commuting trips account for the biggest percentage of trips during the AM and PM peak. During the interpeak, most of the journeys recorded were Other trips.

Table 3.3 shows the proportion of roadside interview records for each site by journey purpose in the interpeak hour of 1100-1200. For site B2 no interviews were recorded for commuting trips, but flows at this location are low (less than 200 cars/hour) and few commuting trips would be expected between 1100-1200. Table 3.4 provides the same information for the pm peak hour of 1700-1800. Before duplicated trips were removed, 50% of the survey responses at Site B1 were commuting trips. However the majority of these trips also passed through one of the other RSI sites, and the table only refers to trips which did not pass through another site.

The journey purpose split of the raw site data is shown in Tables 3.2 to 3.4. The final purpose split for the total observed data for each time period is shown in Table 3.5.

Table 3-2: AM RSI Matrices by Journey Purposes Site 1 Site 2 Site A Site B1 Site B2 Site C

Commuting 59% 71% 47% 47% 47% 50%

Business 6% 10% 12% 16% 14% 11%

Other 33% 15% 29% 29% 35% 22%

HGV 2% 4% 13% 8% 4% 17%

Table 3-3: Interpeak RSI Matrices by Journey Purposes Site 1 Site 2 Site A Site B1 Site B2 Site C

Commuting 8% 6% 12% 12% 0% 5%

Business 18% 32% 13% 8% 51% 23%

Other 71% 57% 71% 71% 43% 58%

HGV 3% 6% 4% 9% 6% 15%

Table 3-4: PM RSI Matrices by Journey Purposes Site 1 Site 2 Site A Site B1 Site B2 Site C

Commuting 40% 53% 48% 12% 58% 53%

Business 12% 7% 1% 6% 9% 8%

Other 48% 39% 44% 74% 30% 31%

HGV 0% 1% 8% 7% 3% 7%



10

Table 3-5: Final observed data purpose split AM IP PM

Commuting 52% 8% 44%

Business 11% 19% 7%

Other 28% 66% 45%

HGV 8% 7% 5%

3.2 Matrix Estimation

Not all trips in the CPR area were interviewed, but total traffic needs to be represented in the model in order to properly represent congestion and journey times. Trips which were not interviewed were generated using a matrix estimation procedure.

Prior matrices for use in matrix estimation were created by combining the RSI site matrices together with

� A30 through traffic

� Seeds for internal Camborne Pool Redruth trips

All of the through A30 traffic was added between the zones representing the southwest part of Cornwall and the rest of the UK as no origin destination information for these trips was available. A30 through traffic was added to these matrices to ensure full traffic levels on the A30 were modelled. The ‘seeding’ of trips for the internal matrix areas was done by adding a very small number of trips e.g. 0.03 to all internal zone pairs. During the matrix estimation process trips between sectors that would pass through RSI locations were frozen.

Forty one traffic counts were carried out within the study area in June 2005 and a selection of these were used in the matrix estimation process. Turning counts at 11 key junctions were retained for validation. Figure 3.2 shows the count locations and indicates which counts were used in matrix estimation and which were kept back for validation.

Appendix C contains tables for the am, interpeak and pm peak period showing the percentage and absolute change in sector to sector trip numbers between the prior matrix and the final validation assignments. The highlighted cells indicate the sector to sector movements frozen during matrix estimation. In addition, tabulations of the absolute values for prior and post matrices are provided.

During the definition of sectors for matrix estimation, two zones were incorrectly allocated which resulted in trips to and from these zones not being frozen. A sensitivity test has been undertaken to identify the impact of this error on the scheme benefits and is described in the Economic Assessment report. The conclusion is that correcting the error does not have a significant impact on scheme benefits.

Figures 3.3 to 3.8 show the trip length distribution for the am, interpeak and pm peak period comparing the distribution of the prior assignment with the final assignments after matrix estimation. The estimation process has increased the proportion of shorter trips but the overall distribution remains similar. As expected, the additional short trips are primarily those within the RSI cordon within Camborne-Pool-Redruth.

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Figure 3-3: AM Peak Trip Length Distribution Proportions

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Figure 3-4: Interpeak Trip Length Distribution Proportions

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Figure 3-5: PM Peak Trip Length Distribution Proportions

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Figure 3-7: Interpeak Trip Length Distribution Trip Numbers

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15

4. 2005 Base Year Assignment The trip matrices were assigned to the network using Wardrop user equilibrium and generalised cost coefficients calculated using time and operating cost coefficients from Webtag. Table 4.1 below shows the generalised cost coefficients used for the assignment.

Table 4-1: Generalised Cost Coefficients Pence per minute (PPM) Pence per kilometre (PPK)

AM IP PM AM IP PM

Light vehicles - Commuting

1.00 1.00 1.00 0.76 0.76 0.76

Light vehicles – Employers Business

1.00 1.00 1.00 0.23 0.23 0.23

Light vehicles – Other trips

1.00 1.00 1.00 0.58 0.58 0.58

HGV 1.00 1.00 1.00 2.24 2.24 2.24

The convergence criteria used for each of the am, interpeak and pm peak models from DMRB Volume 12 (Section 2 Part 1 Appendix H) are shown in Table 4.2.

Table 4-2: Convergence Criteria Convergence Measure Acceptable Value

Duality gap � Less than 1%

AND one of the following

Percentage of links with flow change < 5% Four consecutive iterations greater than 95%

RAAD in flows Less than 1%

AAD in flows Less than 1 veh/hr

To ensure the model was well converged, the validation criteria for flow changes between assignment/simulation loops was tightened to a difference of 3%. Table 4.3 below shows the final convergence parameters achieved for each of the modelled periods.

Table 4-3: Achieved Convergence Time period Duality Gap (%) No of loops with flow

change <3% RAAD (%) AAD (pcu/hr)

AM 0.022 4 0.33 0.57

IP 0.002 4 0.19 0.27

PM 0.027 4 0.34 0.64



16

5.1 Introduction

Model calibration refers to the process of adjusting and confirming values of the various parameters to improve the performance of the model by making use of the data collected during the study, as necessary.

Model validation demonstrates that the calibrated model reproduces observed conditions, within an acceptable range, when applied in the base year. The calibration and validation results of the models developed in the previous Chapters are presented and analysed in this Chapter.

5.2 Validation Criteria

The validation acceptability guidelines as set out in DMRB Volume 12 Section 2 Part 1 Chapter 4 are summarised in Table 5-1.

Table 5-1: Assignment Validation - Acceptability Guidelines Criteria and Measures Acceptability Guideline

Assigned hourly flows compared with observed flows For flows < 700 vph – Individual flows within 100 vph; For flows 700 – 2700 vph - Individual flows within 15%; For flows > 2700 vph – Individual flows within 400 vph.

85% of all cases

Total screenline flows (normally > 5 links) to be within 5%.

All (or nearly all) screenlines

GEH statistic GEH < 5 for individual flow; GEH < 4 for screenline.

85% of cases All (or nearly all) screenlines

Modelled journey times compared with observed times. Times within 15% or 1 min (if higher)

> 85% of routes

Notes: Screenlines containing high flow routes such as motorways should be presented both including and excluding such routes.

5.3 Calibration Results

In total 250 counts (include 12 link counts and 238 turning counts) at 36 locations were used in the matrix estimation process of which all of them meet the DMRB validation requirement for both light vehicles and HGVs. The results were summarised in Table 5.2.

5. 2005 SATURN Model Calibration and Validation



17

Table 5-2: Flow Calibration Results (Counts used for Matrix Estimation)

Time Period Vehicle Types % Flow with GEH < 5 % Flow within DMRB Recommended Flow Range

LV 90% 97% AM

HGV 92% 100%

LV 94% 100% IP

HGV 95% 100%

LV 91% 95% PM

HGV 94% 100%

5.4 Flow Validation

Table 5.3 shows the results of the 97 validation counts (not used in matrix estimation) at 12 different sites for the three time periods. Each vehicle type in each time period meets the validation criteria for GEH statistics and flow ranges. Details comparison between the observed and modelled flow for each of these 97 counts for three different time period (both Light Vehicles and Heavy Goods Vehicles) can be found in Appendix D. The locations which were validated are highlighted purple in Appendix D..

Table 5-3: Flow Validation Results (Validation Counts)

Time Period Vehicle Types % Flow with GEH < 5 % Flow within DMRB Recommended Flow Range

LV 87% 92% AM

HGV 88% 100%

LV 87% 97% IP

HGV 93% 100%

LV 85% 94% PM

HGV 88% 100%

Figures 5.1 to 5.3 show modelled and observed flows on key links in the am peak, interpeak and pm peak periods.

East Hill double mini roundabout in Pool is a key junction in the network and Tables 5.4 to 5.6 show how the modelled and observed flows compare for each turning movement at this junction in each time period.

In each time period all bar one of the turning movements meets the required flow criteria of being within 100 vehicles of the observed count. The validation against the GEH statistic is not as good with the modelled flows between Trevenson Road and Tolvaddon Road being lower than the observed in each direction and time period.



18

Table 5-4: East Hill AM Peak Validation Turning Movement Observed

Flow (veh) Modelled Flow

(veh) GEH Flow

Difference Criteria

East Hill to Tolvaddon Road 464 529 2.90 �

East Hill to Trevenson Road 464 506 1.89 �

East Hill to Dudnance Lane 82 69 1.53 �

Tolvaddon Road to Trevenson Road 191 77 9.88 x

Tolvaddon Road to Dudnance Lane 101 92 0.87 �

Tolvaddon Road to East Hill 194 246 3.48 �

Trevenson Road to Dudnance Lane 32 9 5.01 �

Trevenson Road to East Hill 399 407 0.39 �

Trevenson Road to Tolvaddon Road 130 53 8.07 �

Dudnance Lane to East Hill 79 52 3.39 �

Dudnance Lane to Tolvaddon Road 153 144 0.75 �

Dudnance Lane to Trevenson Road 47 8 7.43 �

Table 5-5: East Hill Interpeak Peak Validation Turning Movement Observed

Flow Modelled Flow GEH Flow

Difference




Tolvaddon Road to Trevenson Road 172 60 10.42 x





Trevenson Road to Tolvaddon Road 162 71 8.41 �






19

Table 5-6: East Hill PM Peak Validation Turning Movement Observed

Flow (veh) Modelled Flow

(veh) GEH Flow

Difference




Tolvaddon Road to Trevenson Road 109 21 10.93 �





Trevenson Road to Tolvaddon Road 193 66 11.18 x






20

Figure 5-1: AM Peak Network Flows



21

Figure 5-2: Interpeak Network Flows



22

Figure 5-3: PM Peak Network Flows



23

Figure 5.4 shows five screen lines, including one East–West screenline south of the A30 and four North-South screenlines through the study area. The appropriate values have been extracted from the validation and calibration spreadsheets and are shown in Tables 5.7 to 5.12 below. The screenlines contain a combination of validation (independent) and calibration (matrix estimated) locations.

The key screenlines which include most traffic and would be most affected by the scheme are South of A30, Pool, and Camborne East. In the am peak, the screenline DMRB criteria are met for both light and heavy vehicles. In the inter-peak, the model under-estimates heavy vehicle traffic across the South of A30 screenline. The maximum shortfall on any link is 25 heavy vehicles/hour. In the pm peak, the model over-estimates heavy vehicle traffic across the Camborne East and Pool screenlines. The maximum over-estimate on any link is 90 heavy vehicles/hour.

The model therefore provides a good representation of light vehicle traffic, and does not have a systematic over- or under-estimate of heavy vehicle traffic.

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Table 5.7: AM Peak Light Vehicle Screenlines

Diff % DiffLocation Date <700 700-2700 >2700 GEH Flow GEHSouth of A30 Screenline - Southbound

A 566 704 138 - - 5.5 � �B,C 213 204 -9 - - 0.6 � �D 623 635 12 - - 0.5 � �E 333 336 3 - - 0.2 � �F 701 636 - -9.3% - 2.5 � �G 991 1021 - 3.0% - 0.9 � �

All 3427 3536 - - 109 1.9 � �South of A30 Screenline - Northbound

A 570 634 64 - - 2.6 � �B,C 89 116 27 - - 2.7 � �D 464 484 20 - - 0.9 � �E 245 263 18 - - 1.1 � �F 681 703 22 - - 0.8 � �G 426 337 -89 - - 4.6 � �

All 2475 2537 - 2.5% - 1.2 � �

Camborne West Screenline - EastboundA,B 173 163 -10 - - 0.8 � �C 545 492 -53 - - 2.3 � �D 528 554 26 - - 1.1 � �

All 1246 1209 - -3.0% - 1.1 � �Camborne West Screenline - Westbound

A,B 224 315 91 - - 5.5 � �C - - - - - -D 459 503 44 - - 2.0 � �

All 683 818 135 - - 4.9 � �

Camborne East Screenline - EastboundA 156 178 22 - - 1.7 � �B 720 745 - 3.5% - 0.9 � �C 64 47 -17 - - 2.3 � �

All 940 970 - 3.2% - 1.0 � �Camborne East Screenline - Westbound

A 122 225 103 - - 7.8 � �B 488 428 -60 - - 2.8 � �C 121 122 1 - - 0.1 � �

All 731 775 - 6.0% - 1.6 � �

Pool Screenline - EastboundA 75 73 -2 - - 0.2 � �B 181 184 3 - - 0.2 � �C 584 680 96 - - 3.8 � �

All 840 937 - 11.5% - 3.3 � �Pool Screenline - Westbound

A - - - - - -B - - - - - -C 652 648 -4 - - 0.2 � �

All 652 648 -4 - - 0.2 � �

Redruth Screenline - EastboundA 122 118 -4 - - 0.4 � �B - - - - - -C 300 159 -141 - - 9.3 � �D - - - - - -

All 422 277 -145 - - 7.8 � �Redruth Screenline - Westbound

A - - - - - -B 83 65 -18 - - 2.1 � �C 96 44 -52 - - 6.2 � �D 197 226 29 - - 2.0 � �

All 376 335 -41 - - 2.2 � �

Flow Criteria (vph)Observed

FlowModelled

FlowWithin DMRB

Documents

Camborne Pool Redruth Transport Package · 2014. 1. 6. · 291073 ITD ITW 3 B P:\Southampton\ITW\Projects\291073 cpr 2011\wp\CPR BFFB LMVR noFig AppAD RevB comp doc 12 August 2011