Prepared by Michael Lloyd Checked by Michael Rolfe

Approved by Michael Rolfe

Over a Century of Engineering Excellence -1-

CORNWALL COUNCIL

CORE STRATEGY MODELLING – INDIVIDUAL TOWN MODELS

TN03/02: FALMOUTH AND PENRYN SATURN MODEL UPDATE (FINAL)

16 DECEMBER 2011 PROJECT: WHV285300DS

1 INTRODUCTION

1.1 Background

1.1.1 Parsons Brinckerhoff has been commissioned by Cornwall Council (CC) to update the traffic model of Falmouth/Penryn to assess the impact of development on the highway network in order to inform the Core Strategy.

1.1.2 An existing SATURN model was developed by Mott MacDonald and provided by CC which represents 2006. The model network was a combination of previously established models for Camborne, Pool, Redruth, St Austell, Truro, Penryn, and Falmouth and incorporated all main roads in Cornwall.

1.1.3 The towns of Falmouth and Penryn were cordoned from the rest of the existing network at the A39 (southbound) and A393 approaches to Four Cross junction to the north of Penryn and at Longdowns to the west.

1.1.4 For the purposes of this project, models have been constructed for the AM Peak hour (0800 to 0900) and PM Peak hour (1700 to 1800).

1.2 Report Structure

1.2.1 The purpose of this technical note is to summarise the work carried out in updating the existing Falmouth model and developing it for use in forecasting. The note is structured as follows:

• Section 2 – details the updates and amendments made to the model network; • Section 3 – outlines the methodology employed to update the demand matrices to 2010; • Section 4 – compares the updated models with 2010 validation counts; and • Section 5 – presents the conclusions of this work.

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 2 - 16 DECEMBER 2011 PROJECT: WHV285300DS

2 UPDATES TO EXISTING MODELS

2.1 Network Checks

2.1.1 A number of network coding aspects have been checked, and where necessary updated, following a review of the warnings and error messages generated by SATURN when compiling the network (ufn) files. These checks included:

• Link speed consistency between the two directions of travel; • Saturation flows at junctions and speed flow curves on key links to ensure consistency

with other models produced as part of this commission; • Coding accuracy, checking that the network is updated to reflect any new infrastructure

changes in place after 2003; • Speed flow curves, ensuring that the same speed flow curves are used for the new links

as for the original network and that the curves used are appropriate for the road types.

2.2 Network Updates

2.2.1 A thorough review of the existing model was conducted and the following changes made to the network:

• A39 / A394 / Treliever Rd (nodes 11998 and 11999): A39 (southbound) approaching nodes 11998 and 11999 adjusted to 2 lane entries.

• A39 / A393 / B3292 (nodes 19011 and 11070): A39 (northbound) / B3292 / A39 (southbound) converted to 2 lane approaches.

• Quay Hill / B3292 (Node 11030): Designated right turn lane from Commercial Road to Quay Hill removed

• A39 / B3292 / A39 Falmouth Rd (Node 12002): B3292 and both A39 approaches converted to 2 lane entries.

• A39 Falmouth Rd / N Parade (Node 11015): North Parade and both A39 approaches converted to 2 lane entries.

• A39 / Union Rd (Node 12001): Union Road and both A39 approaches converted to 2 lane entries.

• A39 / Antron Hill / Kernick Rd (Node 12000): All approaches converted to 2 lane entries. • Mabe Burnthouse Junction - Antron Hill / Treliever Rd / Church Rd (Node 11052): Junction

recoded to reflect current junction layout. • A39 / Kimberley Park Rd (Node 11012); Kimberley Park Road (eastbound) approach

converted to one lane. • Tregenver Rd/ A39 / Killigrew St (Node 11005): Additional lanes / correct lane allocations

coded. • (Node 11007): A39 (northbound) approach converted to 2 lane entry.

2.2.2 In addition to the above stated changes to the network, it was ensured that HGV access routes to and from Falmouth docks (Zone 115) were coded into the model.

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 3 - 16 DECEMBER 2011 PROJECT: WHV285300DS

3 2010 DEMAND MATRICES

3.1 Background Growth

3.1.1 When updating the model, a background growth rate has been applied to bring the overall volume of trips within the matrices to the expected level for 2010. Some new developments completed between 2006 and 2010 have been applied separately, as detailed in Section 3.2 below.

3.1.2 The growth rates have been taken from the NTEM (National Trip End Model) which outlines the growth factors for all areas of the UK. For this study, the growth factors between 2006 and 2010 for the Falmouth and the Penryn area have been used.

3.1.3 These growth factors contain a certain number of planning assumptions, for new developments which are expected in the area during the specified period. As part of this study, a number of developments have already been specified by Cornwall Council; therefore to ensure no double counting has taken place, these developments have been removed from the future planning assumptions in NTEM.

3.1.4 The growth rates applied to the morning and evening peak periods are given in Table 3.1 below.

Table 3.1: Background Growth Rates

Growth Period AM Peak PM Peak 2006 – 2010 1.0370 1.0595

Source: NTM AF09

3.2 Developments

3.2.1 The effect on trip generation of some developments completed between 2006 and 2010 has been modelled explicitly, rather than including them in the background growth detailed above. The developments included in this way are listed below:

• Land off Poltair Road, Penryn; • Land off West Street, Dunstan View; • Andrewartha Road, Penryn; • West End/Tresooth Lane, The Praze; • Penryn Bridge Boatyard, Eastwood Road; • Land adjoining College Hill; • Collingbourne & Somerdale, Seaview Road; • Goldenbank, Phase 5, Falmouth; • Land adjoining the Palm Court; • Millennium Club Site, Falmouth; • Falmouth Maritime Site – Block A, Grove Place car park; • Kimberley Croft, Trevethan Rise; • Former school, Clare Terrace, Falmouth; and • Lidl, Falmouth Road

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 4 - 16 DECEMBER 2011 PROJECT: WHV285300DS

3.2.2 In order to reflect the difference in trip patterns between developments located in different areas of town, the sites listed above have been classified as Town Centre, Suburban Area or Edge of Town for the purposes of trip generation.

3.2.3 As no data was available at the time of the development of the model, the trip rates have been derived using the TRICS database. As there were limited surveys on the database for residential developments within the Cornwall region, comparable housing developments have been chosen from similar rural areas of the UK. This is considered acceptable as the developments were split further into their location in relation to a town centre.

3.2.4 The trip rates used to calculate the volume of demand arriving at or leaving each development site in the morning and evening peak periods are presented in Table 3.2.

Table 3.2: Residential Development Trip Rates

Development Location

AM Peak PM Peak In Out In Out

Town centre 0.18 0.26 0.21 0.22 Suburban area 0.12 0.34 0.35 0.18 Edge of town 0.11 0.37 0.34 0.18

Note: Values represent the generated number of car trips per dwelling split by direction and peak period.

3.2.5 The trip generation from each development is calculated by combining these trip rates with the number of units completed and is presented in Table 3.3. The trips have been added into the model zone which includes that development site, with the existing distribution of trips used to determine their origins or destinations as appropriate.

3.2.6 Zones that have been added to the model to explicitly load new development trips onto the network have assumed the same distribution as nearby zones with similar land use.

Table 3.3: Residential Development Trip Generation

Development Location Units

Completed 2005-2010

Type AM Peak PM Peak

In Out In Out

Poltair Road 61 Edge of Town 7 23 21 11 West Street 72 Suburban 9 24 25 13 Andrewartha Road 10 Suburban 1 3 4 2 The Praze 30 Edge of Town 3 11 10 5 Eastwood Road 22 Town Centre 4 6 5 5 College Hill 43 Edge of Town 5 16 15 8 Seaview Road 24 Edge of Town 3 9 8 4 Goldenbank 108 Edge of Town 12 40 37 19 Palm Court 10 Suburban 2 6 6 3 Millennium Club 14 Suburban 2 5 5 3 Falmouth Maritime Site 14 Town Centre 3 4 3 3 Trevethan Rise 10 Suburban 1 3 4 2 Clare Terrace 11 Town Centre 2 3 2 2

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 5 - 16 DECEMBER 2011 PROJECT: WHV285300DS

Note: Values represent the generated number of trips per dwelling split by direction and peak period.

3.2.7 The network was also updated to include trips generated from the Lidl supermarket which opened near Ponsharden roundabout in 2009. The trip rate has been taken from the TRICS database, which has been calculated from comparable supermarket sites located in the South West region.

3.2.8 Table 3.4 presents the trips generated from the development.

Table 3.4: Lidl Development Trip Generation

Trip Rates Trips Generated

AM Peak In 3.21 34 Out 2.31 25

PM Peak In 6.19 66 Out 6.65 71

3.2.9 As part of the Falmouth model, the volume of trips generated by the Tremough Campus was updated to reflect the current student numbers, as supplied by Cornwall Council. The distribution of trips to and from this site has been maintained from the previous version of the Falmouth model.

4 VALIDATION

4.1 Introduction

4.1.1 The updated model has been validated using link flows from counts at the following locations:

• High Street; • Kimberley Park Road; • Killigrew Street; • Market Street; • Melville Road; • Avenue Road; • Swanpool Road; • Dracaena Avenue; • North of Treliever Roundabout; • Kernick Road; and • Falmouth Docks

4.1.2 Link flow data was obtained from traffic counts undertaken from 2007 to 2010. These were obtained from Cornwall Council.

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 6 - 16 DECEMBER 2011 PROJECT: WHV285300DS

4.1.3 All flow data has been factored up to 2010 data values, to maintain consistency with the other Town Models produced by PB. These were growthed using factors calculated from traffic data which was continuous between the years of 2006 and 2010. Data was obtained from Cornwall Council for a number of Automatic Traffic Counts (ATCs) located in and around St Austell. No other ATCs in Cornwall was available to give continuous data over the period needed. Data from the Strategic Road Network (SRN) is not representative of the changes in local trip volumes which form the principal focus of this study.

4.2 Model Validation Methodology

4.2.1 The GEH (Geoffrey Edward Havers) statistic has been used to assess the fit between the observed and the modelled flows. The link flow criteria used to assess the acceptable performance of a traffic model are defined in DMRB Volume 12 and are summarised below:

• Link Flow Test 1: Observed flow < 700 vph – over 85% of links with the modelled flow within ±100 vph (vehicles per hour) tolerance;

• Link Flow Test 2: Observed flow 700 to 2,700 vph – over 85% of links with the modelled flow within ±15% tolerance;

• Link Flow Test 3: Observed flow > 2,700 vph – over 85% of links with the modelled flow within ±400 vph tolerance; and

• GEH Test: Over 85% of links with GEH statistic less than 5.

4.3 Model Validation Results

4.3.1 A link flow diagram with the observed and the modelled flows for both the AM and the PM Peak are shown in Figure 1 and 2 respectively.

4.3.2 The validation results for each of the links tested in the morning peak model are given in Table 4.1.

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 7 - 16 DECEMBER 2011 PROJECT: WHV285300DS

Table 4.1: AM Peak Validation Results

Link Direction Observed Modelled GEH Flow Test 1

Flow Test 2 Overall

High St One-way 132 105 2.5 -

Kimberley Park Road

Eastbound 230 289 3.7 -

Westbound 262 239 1.4 -

Killigrew St Eastbound 143 175 2.6 -

Westbound 175 130 3.7 -

Market St One-way 158 158 0.1 -

Melville Rd (E) Eastbound 165 116 4.1 -

Westbound 204 164 2.9 -

Melville Rd (W) Eastbound 320 269 3.0 -

Westbound 240 249 0.6 -

Avenue Rd Southbound 72 113 4.3 -

Northbound 130 140 0.9 -

Swanpool Rd Eastbound 164 183 1.4 -

Westbound 105 119 1.3 -

Dracaena Ave Southbound 739 828 3.2 -

Northbound 673 761 3.3 -

North of Treliever Rbt

Southbound 842 789 1.9 -

Northbound 846 961 3.8 -

Kernick Rd Eastbound 618 666 1.9 -

Westbound 551 456 4.2 -

Falmouth Docks Eastbound 84 98 1.5 -

Westbound 26 57 4.7 - Note: No link flows are high enough for Link Flow Test 3, which is therefore omitted.

4.3.3 Table 4.2 summarises the validation of the AM peak model in the three flow categories as defined in DMRB. 100% of links with flow between 700-2700 vph pass, and 100% of links with flow less than 700 vph pass, giving an overall pass rate of 100%.

Table 4.2: AM Peak Validation Summary

Link Description Number of Links Passed % Passed

Individual links with flow less than 700 vph 19 19 100.0%

Individual links with flow between 700 - 2,700 vph 3 3 100.0%

Individual links with flow greater than 2,700 vph - - -

Summary 22 22 100.0% GEH < 5 22 22 100.0%

4.3.4 The detailed validation results for each of the links tested in the evening peak model are given below in Table 4.3.

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 8 - 16 DECEMBER 2011 PROJECT: WHV285300DS

Table 4.3: PM Peak Validation Results

Link Direction Observed Modelled GEH Flow Test 1

Flow Test 2 Overall

High St One-way 190 153 2.8 -

Kimberley Park Road

Eastbound 290 305 0.9 -

Westbound 266 336 4.0 -

Killigrew St Eastbound 246 167 5.5 -

Westbound 124 172 4.0 -

Market St One-way 201 272 4.6 -

Melville Rd (E) Eastbound 299 230 4.3 -

Westbound 152 143 0.8 -

Melville Rd (W) Eastbound 302 294 0.5 -

Westbound 423 339 4.3 -

Avenue Rd Southbound 126 160 2.8 -

Northbound 131 118 1.2 -

Swanpool Rd Eastbound 149 149 0.0 -

Westbound 232 233 0.0 -

Dracaena Ave Southbound 849 856 0.2 -

Northbound 717 792 2.7 -

North of Treliever Rbt

Southbound 910 946 1.2 -

Northbound 873 992 3.9 -

Kernick Rd Eastbound 216 270 3.5 -

Westbound 515 472 1.9 -

Falmouth Docks Eastbound 19 43 4.3 -

Westbound 85 126 4.0 - Note: No link flows are high enough for Link Flow Test 3, which is therefore omitted.

4.3.5 Table 4.4 summarises the validation of the PM peak model in the three flow categories as defined in DMRB. 94.4% of links with flow less than 700vph pass and 100% of links with flow between 700-2700vph pass. The overall link flow pass rate for the PM peak is 95.5%.

Table 4.4: PM Peak Validation Summary

Link Description Number of Links Passed % Passed

Individual links with flow less than 700 vph 18 17 94.4%

Individual links with flow between 700 - 2,700 vph 4 4 100%

Individual links with flow greater than 2,700 vph - - -

Summary 22 21 95.5% GEH < 5 22 21 95.5%

Falmouth and Penryn SATURN Model Update Core Strategy Modelling – Individual Town Models

Over a Century of Engineering Excellence - 9 - 16 DECEMBER 2011 PROJECT: WHV285300DS

5 CONCLUSION

5.1.1 The Falmouth model has been updated to include background growth and developments in Falmouth between 2006 and 2010. Both the AM and PM models have been validated against recent link counts and it has been demonstrated that the models meet DMRB criteria. It can therefore be concluded that the models are a good representation of the Falmouth and Penryn area and are suitable for use in forecasting of the impact of development on the highway network.

5.1.2 It should be noted that the calibration and validation process of the SATURN model is based on link data and that a model is unlikely to fully calibrate and validate with observed traffic flows on all links of the model. A SATURN model is used at a more strategic level to identify route choice through the network. The expected next phase of this study is to look at individual junctions using specialist software. This phase will take into consideration any large differences between observed and modelled flows and a manual correction process will be carried out where appropriate.

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Modelled FlowSurveyed Flow

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GEH and Link Flow Test Failure

Link Flow Test Failure Only

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269320

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CLIENT: PROJECTCornwall Council: Core Strategy Modelling - Individual Town Models

Carrick House, Pydar Street,

Truro, TR1 1EB

Tel: (01872) 224 241Web: cornwall.gov.ukLink Flows: Falmouth and Penryn - Base Flows - AM

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Modelled FlowSurveyed Flow

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CLIENT: PROJECTCornwall Council: Core Strategy Modelling - Individual Town Models

Carrick House, Pydar Street,

Truro, TR1 1EB

Tel: (01872) 224 241Web: cornwall.gov.ukLink Flows: Falmouth and Penryn - Base Flows - PM

TITLE

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E:\Dissertation\SurveyID3191 - data analysis 1.xlsx

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The Forum, Barnfield Road, Exeter EX1 1QRTel: (01392) 229 700 Web: pbworld.com

DATE

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SCALE

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PRODUCED

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