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Technical note

Project Local Development Framework Date 29 August 2008 Note TN4 - Scenario Tests – August 2008 Ref CTLAUF/TN5 Author

1 Summary 1.1 This report describes the findings from a series of tests of the transport performance of a range of land use options for Aylesbury, to help inform decisions on preferred directions of growth. The options include growth in a generally Eastern direction, growth in a generally Southern direction, and a Combined option taking elements from both the Southern and Eastern options. Results are also included for a Northern option which is not favoured by District Council but has been tested because it is understood that development of a major site in the area is likely to be promoted by developers as a means of meeting part of Aylesbury's housing requirement.

1.2 In developing the growth scenarios, a number of transport strategy measures have been incorporated in addition to the roads required to access the new development areas. One major concern to decision makers has been the extent to which Eastern Link Roads connecting the A41 Road to the A418 east of , with a spur towards the town centre, need to be provided as an integral part of the growth strategy regardless of whether they are needed for direct access to new development. The tests have therefore been carried out both with and without full Eastern Links.

1.3 The key conclusions from the tests are:

• Congestion will worsen in Aylesbury in the future, particularly in the AM and PM peaks • Overall congestion in the interpeak will be worse than current peak period congestion levels • The tests show similar levels of travel conditions for the four land use options • The tests show that the congestion indices for 2026 are similar to 2013. This shows the need for the transport strategy measures including the public transport services, link roads and smarter choices measures Technical note Page 2

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

• The tests without the Eastern Links show a marked worsening of congestion

1.4 Based on a single overall measure of highway transport efficiency (the total generalised cost of travel), the final option rankings emerging from the transport model scenario tests for options with the Eastern links are:

• 1st: Eastern • 2nd: Southern • 3rd: Combined • 4th: Northern

1.5 In terms of environmental impacts, the use of generalised cost alone to determine rankings may not be entirely satisfactory. An accurate measure of environmental impacts might have to give higher weight to total distance travelled and to queuing time than to the other elements of generalised cost. On any weighting of the different parameters, the Northern option would remain at the bottom of the rankings and the Combined option would probably remain third, but the better performance of the Southern option in respect of total distance travelled could put it on a par with or slightly above the Eastern option.

2 Introduction 2.1 In 2005 County Council (BCC) and Aylesbury Vale District Council appointed consultants to develop the Aylesbury Land Use Transport Strategy Model (ALUTS). The purpose of this model is to provide a tool to assess the impact of growth arising from major developments proposed in the town. The model has been used to test a range of alternative land use / transport scenarios for the town to assist with the development of the Local Development Framework (LDF). This note describes the testing that has been undertaken in August 2008.

3 The ALUTS Framework 3.1 The ALUTS modelling framework is shown in figure 1. The regional model provides external trip matrices for use in the local Aylesbury model. These can be developed using trip end forecasts provided by NTEM or by bespoke planning data sets. The local model is multi-modal in nature and incorporates assignment and demand sub models. Technical note Page 3

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

Figure 1: ALUTS Modelling Hierarchy

BCC REGIONAL Model

LOCAL ALUTS MODEL

STRATEGY DEVELOPMENT & APPRAISAL

3.2 The development of the regional model recognised that the influences on Aylesbury extend far beyond the current catchment area for the town. There are a number of sub-regional influences through major developments, transport schemes and wider transport policy that would affect the town. Thus a bespoke regional model, suitable for BCC’s use was developed. The aim of the regional model is that it should:

• cover a sufficient area to address the regional influences on Aylesbury - these should include the whole of Buckinghamshire and extend to include London, Oxfordshire, Thames Valley, the MSKM area and part of the East Midlands; • contain an aggregate zone system; • be able to derive trip ends for different planning scenarios; • have a network component representing the main highway network and key public transport links; and • allow for variable demand impacts including mode split and distribution.

3.3 Much of the testing work reported here is based on the Local Model. This comprises highway and public transport network representations with a demand model to forecast changes in trip making in the future. Technical note Page 4

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4 The Local Model

Base Year and time periods

4.1 The base year for the local model is 2005. Trip matrices and networks have been developed for a 12-hour day representing 0700-1900. Assignments within the highway model (using CONTRAM) represent the full 12 hour day broken down into a number of time slices (15 minutes within the peaks and hourly within the interpeak). Within the EMME public transport model, results are obtained for the following time periods:

• Morning peak period between 0700 and 1000; • Interpeak period between 1000 and 1600; and • Evening peak period between 1600 and 1900.

Trip Purposes

4.2 Trip matrices have been developed for a range of travel purposes including:

• Home based work; • Home based employers business; • Home based education; • Home based shopping; • Home based other; • Non home based employers business; and • Non home based other.

4.3 Matrices have been produced for private vehicle and public transport users separately. A further segmentation has been developed to represent car available and non-car available public transport users. For the highway assignments, matrices have also been developed of light vans and other goods vehicles.

Sources of Trip Matrix Data

4.4 The highway matrices are based on a combination of observed and synthetic elements. The observed elements are based on the ALUTS 2005 Roadside Interview Surveys. Time period and purpose matrices have been developed for movements across ALUTS screenlines. Intra-sector movements have been developed using gravity models for each purpose. Technical note Page 5

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

4.5 The rail matrices have been derived from a combination of Network Rail, Department for Transport (DfT) and Transport for London (TfL) data. The data used includes matrices developed for other regional rail models, LATS rail surveys and station observations. The local bus matrices have been developed from census journey to work data and surveys undertaken in Aylesbury town centre.

5 The Forecasting Methodology 5.1 The ALUTS model has been developed to take account of the following influences in travel:

• Changes in the numbers generated in Aylesbury; • Changes in the distribution of trips; • Changes in the choice of mode for trips; • Changes in the time of travel of trips; and • Changes in the choice of route for trips.

5.2 The model is therefore a fully specified ‘demand model’ set up for a base year of 2005 and a flexible future year, which in the case of these tests is 2026. It should be noted that a separate test has been undertaken for 2013 to represent completion of proposals in the Aylesbury Vale District Local Plan (AVDLP).

5.3 The model operates incrementally on base demands in proportion to changes in land use and economic quantities, and transport generalised costs. The demand model operates for each of the trip purposes identified in the previous section.

5.4 Thus the model comprises a number of stages including:

• Stage 1: Trip End Forecasting; • Stage 2: Initial Assignment; • Stage 3: Demand Model • Stage 4: Assignment .

6 2026 LDF Tests 6.1 AVDC have provided 2026 land use assumptions for households and employment by ALUTS model zones. For households information has been provided for completions, allocations under the AVDLP and allocations under the LDF. Information has been provided for Aylesbury and the rest of the district. The summary totals are shown below in Table 1. AVDC provided detailed information on locations with ALUTS zone codes. These are summarised below. Technical note Page 6

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Table 1: AVDC Household Changes 2006-2026 Household Aylesbury Changes Totals AVDLP 6911 Small sites 71 Completions 433 LDF Brownfield 1205 Greenfield 9300 Total 17920 Rest of District AVDLP 1669 Small sites 311 Completions 464 LDF Rest of District 7490* Total 9934 Overall Total 27854 * includes an allocation in AVDC adjacent to Milton Keynes.

6.2 The Greenfield allocation of 9300 households for Aylesbury was the subject of four alternative option tests as shown by Table 2. These four options build upon the notes provided in the AVDC Cabinet Paper on the LDF (April 2008). The Cabinet rejected the Northern option, but in view of the fact that the promoters of the Fleet Marston site intend to pursue the case for inclusion of their site through the LDF formulation and approval processes, it is necessary to continue to provide evidence on the performance of a Northern option for use in the Hearing into the Core Strategy. Following the Cabinet meeting it became clear that the version of a Northern option that had been put to them did not represent the most likely form for an option including Fleet Marston to take, so a different set of allocations has been used in this round of testing. For each option, housing numbers have been identified for a series of sites. Sites C, D, E and F occupy the same general areas designated in this way in the Issues and Options document. New zones have been incorporated into the model with at least 4 zones per site and 6 for the larger sites. The allocations tested in each case are given below. Technical note Page 7

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Table 2: Greenfield Major Development Area (MDA) Housing Allocations Option Northern Eastern Southern Combined Site Fleet Marston 3000 C 4700 4200 Broughton Crossing 1600 1600 1600 D 3500 3300 3300 E 2700 1100 F 3300 3300

6.3 Employment information has been supplied by AVDC. The data included floorspace allocations for completions, AVDLP and LDF allocations. The trip end model forecasts using the number of jobs and so conversion rates are applied to floorspace estimates based on the following ratios:

• Offices (Use Class B1a) 17.9 sq.m. per worker • Industrial (Use Classes B1c & B2) 31.8 sq.m. per worker • Warehousing (Use Class B8) 40.1 sq.m. per worker

6.4 These are the figures recommended by AVDC and used by the consultants who have recently completed an employment land study for AVDC.

6.5 Within the forecasts allowance has been made for a number of major developments (1,000 sq m or more) completed at Aylesbury since March 2006 on windfall, i.e. unallocated, sites and providing employment floorspace or resulting in the loss of such floorspace (sq m). An allowance for the development of the sites already allocated in the AVDLP or the subject of a permission at 2006. These developments include:

• an allocation for employment development at Telford Close (northern corner of Zone 53); the development of this site and an adjoining area was completed in June 2006, providing 6,000 sq m of B2/B8 floorspace; • an allocation for employment development at Stocklake West (eastern end of Zone 18); this development was completed in stages: 1,000 sq m in May 2005 and a further 2,700 sq m in Nov 2006, both B2 floorspace; • two areas at the northern edge of Coldharbour Farm () (eastern part of Zone 55) that were parts of a Mixed Housing/Employment Commitment identified in the AVDLP and have now been developed; they are (1) an area developed since 2006 on the basis of a permission for 8,200 sq m for B2 use and 3,100 sq m for B8 Technical note Page 8

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use; and (2) an area developed on the basis of a permission for 9,000 sq m of B1, B2 and B8 floorspace and completed in Feb 2006.

6.6 Allowance has also been made for each of the following AVDLP allocations that are (a) the subject of a permission for a development that has not been completed or not yet even started; or (b) are not yet the subject of a permission:

• MDA; an allocation now the subject of an outline permission for development including 9ha of employment, split evenly between offices/industrial/warehousing. (The majority of the employment development is expected to be in Zone 57 with the balance in Zone 106); • Aston Clinton Road MDA (NW corner of Zone 85); permission has not yet been granted, but Members considered an application for outline permission; • Stocklake East (eastern end of Zone 18); a 0.8 ha allocation for employment development - most likely B2/B8; • West of Walton Street (Zone 14); permission being implemented for the redevelopment for non-employment uses of part of an allocated site that has resulted in the loss of 1,500 sq m of office floorspace; • Former BPCC factory, Tring Road (central north part of Zone 19); a cleared area representing part of a site allocated for other than employment uses where there used to be 17,500 sq m of industrial floorspace.

6.7 Finally the modelling includes allocations that it is intended should be included in the AVLDF at:

• Aston Clinton Road (on the eastern side of Zone 85, principally to the north of the A41 - and, it is understood, “hung off” the Eastern Link road in the network - but also probably in part to the south of the A41); please allow for the development of 55 ha for offices/industry/warehousing; • College Road North (the central southern part of Zone 86); please allow for the development of 10ha for B2/B8; and • an even distribution of the required balance between the sites proposed for each option. (based on an assumption that 1.4 ha of office floorspace will be provided with each 1,000 dwellings proposed for a site as part of each option).

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6.8 The 2026 forecast number of jobs is some 18515 higher than 2006 (includes primary employment, schools and district centre jobs). BCC also provided the locations of schools as shown in Tables 3 and 4.

Option Northern Eastern Southern Combined Site Fleet Marston (3000 2.5 units) Site C (4700 units) 4 Site C (4200 units) 3.5 Broughton Crossing (1600 units) 1.5 1.5 1.5 Site D (3300 units) 2.5 2.5 Site D (3500 units) 3 Site E (1100 units) 1 Site E (2700 units) 2 Site F (3300 units) 2.5 2.5 Total Primary Schools 8 8 7 7.5 Table 3: Number of Primary Schools

Option Northern Eastern Southern Combined Site Fleet Marston (3000 1 units) Site C (4700 units) 1 Site C (4200 units) 1 Broughton Crossing (1600 units) 1 1 1 Site D (Part) (3300 units) 1 1 Site D (3500 units) 1 Site E (Part) (1100 units) Site E (2700 units) 1 Site F (3300 units) 1 1

Total Secondary Schools 3 3 3 3 Table 4: Number of Secondary Schools Technical note Page 10

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

Planning Data Assumptions- External area Reference Case

6.9 The current tests make use of Tempro version 5.4 for trip growth outside of the Aylesbury Vale District. Tempro 5.4 was issued in early July 2008. There is a technical note available from the DfT (written February 2008) which explains the changes made to the data. These include:

• New 2001 Census Output Area based NTEM zone geography;

• Update of 2001 planning data base;

• Policy-based input dwelling assumptions revised;

• Revised approach for allocating population and households to zones

• Different growth rates in employment by sector and households by type;

• Make use of 2006 based population projections (released October 2007) which forecast higher growth in population and therefore higher number of trips.

6.10 In using the Tempro 5.4 data it is recognised that an announcement was made on revisions to the South East Plan. The Tempro inputs have been adjusted to take account of the SE Plan revisions. The external trip growth is fed from Tempro through the regional model to the local model.

7 Network Assumptions Network Assumptions- Reference Case

7.1 Assumptions were developed for a reference case network for 2026. The assumptions were based on the proposed measures included in regional transport strategies where these were committed, under construction or under detailed consideration. In the local area BCC and AVDC provided assumptions for Aylesbury. Technical note Page 11

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7.2 The measures that are assumed to be common to each of the scenarios include:

• Rail • East west rail link with services between Aylesbury and Milton Keynes; • New stations at Aylesbury North Parkway (2 trains per hour to London) with 1 train per hour to Milton Keynes), Winslow and Newton Longeville; • Highway • Aylesbury PT Hub improvements; • A41 Bicester Road PT corridor measures; • A413 Road PT corridor measures; • A418 Wing and bypasses; • Linslade and bypass; • A Western Link Road between the A41W at Berryfields and the A413 at Weedon Hill; and • An Eastern link between the A418 at Bierton and the A41 Aston Clinton Road • Bus • Aylesbury PT Hub services; • New services to serve the MDA’s (assumed as 1 bus every 10 minutes); • Park and ride services from Berryfields, Weedon Hill and Aston Clinton Road.

Assumptions- Option Tests

7.3 For each option a set of distributor roads were assumed. These are based on the Cabinet Paper drawings. CONTRAM diagrams of the networks are shown below. Each network has been tested with and without the Eastern Links to the extent that these links are not required for access to the Broughton Crossing development.

7.4 The assumptions for the local roads in the MDAs are:

• E Link 50mph • MDA routes – alongside 40 mph • Inside MDA – 30mph • In centres 20 mph (assumed as two lanes in each direction with signals at district centre)

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7.5 Table 5 shows the combinations assumed for the local roads. This is followed by a series of figures (Figure 2) to show the highway networks used for the tests.

Table 5: Network Assumptions Option 2013 Northern Eastern Southern Combined AVDLP Site North Western (A41W- X X X X X A413) Wing –Rowsham Bypass X X X X North Eastern (A413- X X A418) Northern Link (NE Link to X through X through site A418 South of Bierton) site Eastern (A418N-A41E) X X X X

Stocklake Link (from E X X through site X X through site Link to Stocklake) South Eastern (A413S- X through site X through site X through site A41E) Southern (A413S-A418S) X through site X through site

7.6 Bus service - assume a ‘flyer’ service similar to Water-rider to each site based on 4 buses per hour.

7.7 Park and Ride - assumed additional site at

• A418 S

7.8 Smarter choices - In 2004 the DfT announced a 5 year project to demonstrate the effect a sustained package of 'Smarter Choice' measures can have when coupled with infrastructure improvements. Darlington, Peterborough and Worcester were selected from more than 50 local authorities in England who expressed an interest in becoming 'showcase' demonstration towns. The 3 towns share £10m of revenue funding during the project with building and improvement works funded LTP) capital funding. Technical note Page 13

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

Figure 2: ALUTS Highway Model Networks

Northern

21/08/2008 10:39am C:\BUCKS LDF\ALUTS\SIGNALS\ALUTS-A418-2026-LU-A-SIGS.NET CONTRAM8 © Mott MacDonald Ltd & TRL Ltd Technical note Page 14

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Eastern

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Southern

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Combined

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Northern without Eastern Link

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Eastern without Eastern Link

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Southern without Eastern Link

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Combined without Eastern Link

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7.9 The starting mode shares for travel within the towns are shown in table 6. In each case there is over 60% travel by car with Darlington having the lowest share. Public transport (PT) use is highest in Darlington at the start of the demonstration while cycling is highest in Peterborough at the start of the demonstration project.

Town PT Use Walking Cycling Car trips (driver + passenger Darlington 12% 25% 1% 41% + 21% Peterborough 6% 22% 5% 43% +23% Worcester 6% 25% 3% 45% +21% Table 6: Initial Mode Shares within the Demonstration Towns

7.10 44% of car journeys in Darlington were identified as having no sustainable travel mode (STM) alternative (61% in Peterborough and 54% in Worcester)

7.11 The overall changes in travel identified in the first few months of the demonstration projects in 2006 are given in the table below (source - Letter from Secretary of State 2007). These show similar reductions in car trips with corresponding increases in walking, cycling and public transport use.

Town PT Use Walking Cycling Car trips Darlington +14% +29% +79% -11% Peterborough +13% +21% +25% -13% Worcester +22% +17% +36 -12% Table 7: Travel Impacts in Demonstration Towns

7.12 The demonstration towns have managed to achieve a 10%+ reduction in trips resulting from the methods adopted. It is noted from the research that is not clear which trips have been reduced. Therefore in the strategy modelling a 10% reduction is applied to the trip matrix but applied according to different responses by distance (shown on Figure 3):

• 0 to 1 Km a 20% reduction • 1 to 3 km a 15% reduction • 3 to 5 km a 10% reduction • 5 to 10 km a 7.5% reduction • 10 to 50 km a 5% reduction • Over 50km a 2.5% reduction

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Figure 3: ALUTS Modelling Smarter Choices - reductions applied

Reductions

25

20

15 10

5 % Reduction in Car trips Car in % Reduction 0 O to 1 1 to 3 3 to 5 5 to 10 10 to 50 Over 50 Trip Length

8 Results 8.1 Table 8 shows the private vehicle trip matrices for each option. This shows the growth in demand between 2005 and 2026. Of the four option tests, the Southern option has the lowest number of car trips.

Year AM IP PM 12-hr

2005 66041 115176 67222 248439 2013 79873 138810 82380 301062

2026 Northern 89520 154503 92157 336180

Eastern 89540 154788 94504 338831 Southern 88303 153773 91442 333518 Combined 89795 155621 92697 338113 Table 8: Private Vehicle Trip Matrices

8.2 For the southern option the growth arising from the model for the various modes is as follows

• Car trips (pre smarter choices/ mode split etc) = 1.56 • Car trips (post smarter choices/ mode split) = 1.36 • Rail Trips = 1.75 • Bus Trips = 1.69 Technical note Page 23

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• Cycle = 1.92 • Walk = 1.92

8.3 In the other tests the growth in car trips is 1.38 while the growth in the other modes is similar to that for the southern option.

8.4 The forecast usage of the Park and Ride sites is:

• A41 W 483 vehicles • A413N 360 vehicles • A41E 638 vehicles • A418S 479 vehicles

Network Summary Statistics

8.5 The traffic growth forecast within the various scenarios is 36%. (The National Road Traffic Forecasts – NRTF - would give a central growth of 30%). In the local area there is transfer to park and ride and a modest transfer to bus. This growth relates to the 60% growth in households between 2006 and 2026. The traffic growth equates to an annual average growth rate of 1.2%. We have not assumed any additional demand management measures to accompany these option tests.

8.6 Tables 9, 10, and 11 show the summary statistics obtained from the model for each of the modelled periods for these tests (the results of the previous tests are included for comparison). Table 12 provides a summary for the 12-hour period (0700-1900) which combines the periods. These include the total travel time and distance spent within the modelled periods as well as the free moving time. The difference between the total time and the freemove time provides the amount of congestion. This is reflected in a congestion index which is taken as the ratio of the total time and the free move time. The tables also provide the network speed for the whole modelled area (which includes the rural area outside Aylesbury) and a generalised cost index (taken as total time + distance/100).

8.7 It should be noted that further investigation of key hotspots of congestion may identify additional improvements to junctions which could improve the congestion indices. Technical note Page 24

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

AM Actual Actual queuing % change in % change in % change in change in change in Change in Freemove S/f time time Total time Distance Speed Queues CI GC Index delay time distance time distance GC Index Base 15545 485 1864 17894 946841 52.9 9206 1.15 27362 2013 18721 698 4225 23643 1147108 48.5 25326 1.26 35114 127% 32% 21% 5750 200267 7752

2026 Northern 20086 913 4011 25009 1287568 51.5 22998 1.25 37885 115% 40% 36% 7115 340727 10523 Eastern 19758 903 3466 24126 1272028 52.7 18749 1.22 36847 86% 35% 34% 6233 325187 9485 Southern 19816 889 3806 24510 1265204 51.6 21820 1.24 37162 104% 37% 34% 6616 318363 9800 Combined 20110 878 3821 24809 1275943 51.4 21924 1.23 37569 105% 39% 35% 6915 329103 10206

No E link Northern 20886 897 5848 27631 1301585 47.1 36831 1.32 40647 214% 54% 37% 9737 354745 13285 Eastern 20544 879 5429 26852 1281626 47.7 34113 1.31 39669 191% 50% 35% 8959 334786 12306 Southern 20367 851 5833 27050 1259402 46.6 37107 1.33 39644 213% 51% 33% 9157 312561 12282 Combined 20816 843 6368 28027 1281483 45.7 40825 1.35 40841 242% 57% 35% 10133 334642 13479

Table 9: Local Model Summary statistics - Morning peak (0700-1000)

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IP Actual Actual queuing % change in % change in % change in change in change in Change in Freemove S/f time time Total time Distance Speed Queues CI GC Index delay time distance time distance GC Index Base 23418 379 2108 25905 1387207 53.5 2308 1.11 39777 2013 28158 521 3987 32665 1680040 51.4 10834 1.16 49466 89% 26% 21% 6760 292834 9688

2026 Northern 31053 719 4272 36044 1954281 54.2 6289 1.16 55586 103% 39% 41% 10138 567075 15809 Eastern 30727 712 3875 35313 1937930 54.9 5526 1.15 54692 84% 36% 40% 9408 550724 14915 Southern 31010 704 4207 35920 1931881 53.8 5995 1.16 55239 100% 39% 39% 10015 544675 15462 Combined 31204 708 4346 36258 1936812 53.4 5971 1.16 55626 106% 40% 40% 10353 549606 15849

No E link Northern 31850 687 5439 37976 1938371 51.0 8108 1.19 57360 158% 47% 40% 12071 551165 17583 Eastern 31623 680 5189 37491 1923611 51.3 7587 1.19 56727 146% 45% 39% 11586 536404 16950 Southern 31675 674 4934 37282 1914324 51.3 7681 1.18 56425 134% 44% 38% 11377 527118 16648 Combined 31914 676 5036 37625 1925137 51.2 6990 1.18 56877 139% 45% 39% 11720 537931 17099

Table 10: Local Model Summary statistics - Interpeak (1000-1600)

Technical note Page 26

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PM Actual Actual queuing % change in % change in % change in change in change in Change in Freemove S/f time time Total time Distance Speed Queues CI GC Index delay time distance time distance GC Index Base 15602 434 2116 18152 943264 52.0 10834 1.16 27585 2013 19638 649 5285 25571 1185615 46.4 33609 1.30 37427 150% 41% 26% 7419 242351 9843

2026 Northern 21595 831 6775 29200 1355377 46.4 44106 1.35 42754 220% 61% 44% 11048 412113 15169 Eastern 21676 832 6728 29236 1362014 46.6 44277 1.35 42856 218% 61% 44% 11084 418750 15271 Southern 21503 831 7005 29339 1342639 45.8 47282 1.36 42765 231% 62% 42% 11187 399375 15180 Combined 21657 825 6715 29198 1347510 46.2 44687 1.35 42673 217% 61% 43% 11045 404246 15088

No E link Northern 22855 880 9273 33007 1397023 42.3 60264 1.44 46978 338% 82% 48% 14855 453760 19393 Eastern 23207 837 10297 34341 1412893 41.1 68493 1.48 48470 387% 89% 50% 16189 469630 20885 Southern 22540 843 9985 33368 1367693 41.0 64591 1.48 47045 372% 84% 45% 15215 424429 19460 Combined 22644 828 8781 32253 1374116 42.6 59138 1.42 45994 315% 78% 46% 14101 430852 18409

Table 11: Local Model Summary statistics - Evening peak (1600-1900)

Technical note Page 27

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Table 12: Local Model Summary statistics - Combined 12-hour period (0700-1900)

12 hr Actual Actual queuing % change in % change in % change in change in change in Change in Freemove S/f time time Total time Distance Speed Queues CI GC Index delay time distance time distance GC Index Base 54565 1298 6088 61951 3277311 52.9 22348 1.14 94724 2013 66516 1868 13496 81880 4012762 49.0 69769 1.23 122007 122% 32% 22% 19929 735452 27283

2026 Northern 72734 2463 15057 90253 4597226 50.9 73393 1.24 136225 147% 46% 40% 28302 1319915 41501 Eastern 72160 2447 14068 88676 4571972 51.6 68552 1.23 134395 131% 43% 40% 26724 1294661 39671 Southern 72329 2423 15017 89769 4539723 50.6 75097 1.24 135166 147% 45% 39% 27818 1262413 40442 Combined 72972 2411 14883 90265 4560265 50.5 72582 1.24 135867 144% 46% 39% 28313 1282954 41143

No E link Northern 75591 2464 20560 98615 4636980 47.0 105203 1.30 144984 238% 59% 41% 36664 1359669 50260 Eastern 75374 2395 20915 98685 4618130 46.8 110192 1.31 144866 244% 59% 41% 36733 1340820 50141 Southern 74581 2367 20751 97700 4541419 46.5 109380 1.31 143114 241% 58% 39% 35749 1264108 48390 Combined 75373 2347 20185 97905 4580736 46.8 106954 1.30 143712 232% 58% 40% 35953 1303425 48988

Technical note Page 28

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

8.8 The CONTRAM assignment includes 32 time slices. These are based on 15 minute profiles in the peak period and hourly within the Interpeak. It is possible to plot the congestion indices across the day. Figure 4 shows a plot for the Base year run, 2013 and the Eastern option with and without the Eastern Link.

1.8 1.7 1.6 1.5 Base

1.4 2013

1.3 Eastern 1.2 Eastern - 1.1 no E Link 1 0.9

2 4 6 8 4 lice 10 12 14 16 18 20 22 2 26 28 30 s ime T

Figure 4: Congestion Index Plot

8.9 The key messages from the tables are:

• Congestion will worsen in Aylesbury in the future, particularly in the AM and PM peaks • Overall congestion in the interpeak will be worse than current peak period congestion levels • The tests show similar levels of travel conditions for the four land use options • The tests show that the congestion indices for 2026 are similar to 2013. This shows the need for the transport strategy measures including the PT services, link roads and the smarter choices measures • The tests without the Eastern Links show a marked worsening of congestion

Technical note Page 29

Project Aylesbury Local Development Framework Note TN4 - Scenario Tests – August 2008

8.10 Based on a single overall measure of highway transport efficiency, the total generalised cost of travel, the final option rankings emerging from the transport model scenario tests for options with the Eastern links are:

• 1st: Eastern • 2nd: Southern • 3rd: Combined • 4th: Northern

8.11 In terms of environmental impacts, the use of generalised cost alone to determine rankings may not be entirely satisfactory. An accurate measure of environmental impacts might have to give higher weight to total distance travelled and to queuing time than to the other elements of generalised cost. On any weighting of the different parameters, the Northern option would remain at the bottom of the rankings and the Combined option would probably remain third, but the better performance of the Southern option in respect of total distance travelled could put it on a par with or slightly above the Eastern option.