Kent Thameside Transportation Model

Interim Technical Note on Version 6 at 26/10/12

Introduction

1. This note gives a brief summary of the results from the latest runs of the Kent Thameside Transportation model by Jacobs. It has been written with full input from KCC Highways and Jacobs. The figures quoted have not been subject to full checking so may change. It does not give the full detail of the assumptions made, nor does it draw out all the implications as the technical work is on-going. The primary aim of this note is to support the Gravesham Core Strategy, but the full results will also assist with issues across Kent Thameside. It will be replaced by a technical report from Jacobs and separately a fuller exploration of the Gravesham transport issues in consultation with KCC Highways.

2. As noted above this report focusses on Gravesham and is not attempting to address the wider issues across Kent Thameside in relation to the Kent Thameside Strategic Transport Schemes (STIPS), except in so much as it refers to schemes on that list. The latest position on the STIPS schemes was set out in a report to KCC Cabinet on 15 October 2012, which predates this modelling. In any case the STIPS programme is based on the full completion of the permitted development of Eastern Quarry and Ebbsfleet with a notional 2031 end date, and not the 2028 GBC Local Plan date used in this report.

3. At the time of preparation of this note it had not been possible to discuss the modelling results with the Highways Agency, whose input is very important in relation to the A2 junctions. The Highways Agency is committed to carry on analysing the flows at the key trunk road junctions and study specific proposals for their enhancement.

4. The KTS Model has been through a number of stages of evolution, however the land uses in the model runs covered here are:

• 2005 base – validation against known flows for that date

• Version 5 – run in 2009 with a notional end date of 2025, this included the full development then expected under the South East Plan to 2026 plus the whole of Eastern Quarry and Ebbsfleet developments, even though they would not be complete until sometime later. This allowed the full impact of these developments to be taken into account. This run is here used as a high development level test, and as a back reference to earlier technical work.

• Version 6 – run in 2012 to a 2028 end date with the current proposed development in Gravesham Local Plan (4,600 homes), and that in the adopted Dartford Core Strategy (2011) to 2026, plus 2 further years of development in Eastern Quarry and Ebbsfleet.

5. The base model was last validated to 2005 flows, which was before Ebbsfleet International & Domestic Railway Station was open. A sense check is being carried out to compare what is known about flows on the highway and the public transport networks for 2011, compared with what the model predicts for that date. Note that in the land use options discussed above the actual development since 2005 to the date

when the run was specified is included. The land use quantities in the model are therefore those now built plus those expected.

6. The starting position is that with the scales of development proposed in Gravesham and Dartford it is inevitable that the transport network will be subject to more congestion as there will be more people trying to use it. The AM and PM peaks are the main area of concern in Gravesham. The results can be analysed in a number of different ways which aggregate together to give an overall picture.

Base case

7. The initial work has focussed on the V6 without transport interventions – which is the transport network as when specified (in 2005) plus committed transport infrastructure. That is defined as schemes that are either under construction or fully permitted and funded. For Eastern Quarry and Ebbsfleet, various connections and through routes are included to make sense of the sites’ links into the wider highway network, otherwise the results would be distorted.

8. Changes in Gravesham since 2005 include the new A2 alignment and junctions, the diversion of the one-way system round the back of the Civic Centre and the implementation of the Hall Road junction improvements as part of the extension of the Pepper Hill food store. The Fastrack network is assumed, including a link through Eastern Quarry to Southfleet Road and then across the Ebbsfleet development, and also east of Ingress Park via the “Gun Barrel” route to Swanscombe Cross on the A226. The original Fastrack route through Northfleet Riverside is not included but a bus connection is.

9. As the modelling is for a 2028 Local Plan end year there are no assumptions about the rate of development or when various sites may start or be completed within the 2011-2028 period, simply that by the end date the amount of development assumed has occurred. The actual order and rate of development could have a significant impact on what schemes are needed where and when, and how the public transport system would evolve. The overall transport strategy will therefore have to be flexible enough to respond to the actual pace and location of development.

10. Appendix 1 contains an overall summary of the results. As the 2028 run does not include any additional transport schemes (e.g. those in the STIPS list) it represents a worst case. This table gives the position for Kent Thameside as a whole. AM and PM refers to the average of the 3 hour peaks, 7-10 am and 4-7 pm. Through flows (that is those without an origin or destination in Kent Thameside) on A2 and M25 are included. Because of the distribution of the major development sites in Dartford Town Centre, Dartford Thames Waterfront, Ebbsfleet, Eastern Quarry, and Northfleet Riverside the impacts will be greatest in these areas. However because of the lack of additional capacity at certain key junctions, a side effect may be to displace traffic onto other roads and junctions elsewhere.

11. The technical reasons for using a 3 hour peak average are explained in Kent Thameside Transportation Model Local Model Validation Report from 2005.In practical terms peak spreading tends to take place, whereby trips are carried out, so far as is possible, at quieter times. This does mean that the results need further analysis to look at how the network operates at particular times, when there may be significant delays.

12. The results provide a baseline for considering the impact of new transport schemes and considering particular junctions in more detail. The highway network shows a growth in trips of the order of around a third in V5 is now reduced in V6 to around a quarter (24.7%). The number of housing units in version 6 are reduced by 23%, and the floorspace total (all uses) by 55%, though this figure is not very meaningful on its own. The main cause of the differences, as well as the change in the Gravesham Core Strategy proposed numbers and site uses, is the omission of parts of the Ebbsfleet and Eastern Quarry developments that are assumed to be completed post 2028. It is important to keep this in mind as the long term transport strategy will need to take account of all committed development, not just that to 2028.

13. Compared with the 2005 base there is none the less a significant increase in trips across the area which needs to be accommodated. Public transport trips are predicted to rise even more significantly at over 40%, but on a much lower base (see caveats below). Average speed on the highway network (including A2 and M25) drops by between 10% and 17%. In general the PM performance is worse the AM. Over capacity is a measure of the growth in traffic queues at junctions, and improves in the AM peak but not in the PM. Further work would allow these results to be made more specific to Gravesham.

14. Trips on Fastrack Route B plus the 480/490 routes have been looked at in more detail to get a more specific impression of what is changing, these being key east-west bus routes running from Gravesham through to Bluewater and Dartford. The table shows changes in trips for the whole of the three routes, and shows even higher level of increase in trips.

Fastrack B and routes 480/490

Base 2028 % change

AM 733 2,143 192%

PM 1,100 2,208 101%

15. The model assumes that the public transport system is capable of taking the extra demand placed upon it, so additional work will be required to refine where significant capital interventions may be required, and where all that is required is running additional bus services and/or longer trains. Additional Fastrack routes are allowed for in the model, including via Springhead but existing bus routes could also be improved by higher frequencies and bus priority measures.

16. Fastrack has been modelled in such a way that makes it attractive to be used, but which may overstate its impact. Actual experience has been that the service has been successful where the demand exists, but constrained by the rate of development hitherto. That said the number of trips that might be put back on the highway network (assuming that is where they go as opposed to other bus services) by making it less attractive would be relatively small and spread out across the network

17. The simplistic interpretation of these results is that, subject to more detailed work, it will be necessary to enhance public transport provision.

Junctions

18. For version 5, flows at junctions were assessed on the basis of an index computed from the delays at the junction and the volume of flows through it. For this analysis the schemes have been reassessed using the concept of the level of service (LOS). This seeks to assess junctions on the basis of delays that may be experienced in using them. In the case of some of the more complex junctions, the model treats them as separate nodes, and the results are shown for these elements. For example Ebbsfleet has roundabouts B & C treated separately. The table below shows the categories used:

Level of Service LOS

Signalised Intersection

Un-signalised Intersection

A – free flow ≤10 sec ≤10 sec

B – reasonably free flow

10-20 sec 10-15 sec

C – stable flow 20-35 sec 15-25 sec

D – approaching unstable flow

35-55 sec 25-35 sec

E – unstable flow 55-80 sec 35-50 sec

F – forced or breakdown flow

≥80 sec ≥50 sec

19. The times for signalised junctions are higher than for un-signalised as the normal cycle times of the signals means that some delay, on average, is inevitable.

20. Summary results can be seen in Appendix 2, which compares the 2005 base case with the V6 with and without mitigation runs. Given the scale of development involved in Ebbsfleet and Eastern Quarry, the operation of the highway box defined by A2 Ebbsfleet junction, A2 Bean junction, St Clements Way, Stonebridge Road although mainly in Dartford is critical because of the knock on implications within Gravesham. If this part of the highway network is congested it will tend to divert trips onto adjoining parts of the network. The STIPS schemes included are:

• Ebbsfleet Junction

• Bean Junction

• London Road/St Clements Way

• Thames Way dualling

• Rathmore Road Link(highway diversion but note this is primarily a public transport scheme – it has outline consent and a detailed application made)

21. There are no update figures on the level of flows across the network as this run is about redistributing trips that are already in the system, not creating or deleting any existing ones. Given the way the model works a reduction in highway congestion will tend to shift trips off public transport, but the precise impact is subject to the interaction of many variables.

22. The analysis presented here focuses on junction in Gravesham and those that immediately adjoining (the Ebbsfleet junction) and those in Dartford are excluded.

For Kent Thameside purposes it will be necessary to consider the whole area. It is pertinent to point out that the operation of Bean Junction and A226 London Road/St Clements Way at Greenhithe are of relevance since if these are very congested traffic from eastern Quarry and Swanscombe will tend to be displaced towards the Ebbsfleet area.

23. The analysis confirms earlier work that, despite the reduction in development and a significant increase in public transport usage, certain junctions on the highway network do come out as having significant congestion issues. The top junctions in relation to Gravesham are:

• A2 Ebbsfleet (though the Ebbsfleet schemes significantly improves performance)

• A227 Wrotham Road/Coldharbour Rd, Gravesend

• Hall Rd/Old Perry St/Earl Rd, Northfleet

• Pelham Road roundabouts, Northfleet

• Hall Road roundabout , Northfleet (although the impact of STIPS schemes significantly improves performance)

24. An issue that the Highways Agency (HA) has raised in the past has been the implications of the model results for junctions on the A2 because of the three hour averaging process might disguise the possible variations in flow within that time period (i.e. higher peaks within these periods). The HA have previously carried out (using the V5 outputs) a more detailed analysis using a micro simulation model of Ebbsfleet and Bean junctions. This tool allows the observed variations in flow across the 3 hour period to be taken into account and allow possible design solutions to be tested. The results of this work, based on earlier runs of the model, suggest that further testing will be required of these junctions. Concern has also been expressed about the A2 Tollgate junction (A227), however at present there is no technical evidence as to whether this will be a matter of concern.

25. It should also be noted that some junctions have issues at other times of the day than during the peaks. A classic example is Bean where the shopping hours and particular peaks at various times of the year, for example at Christmas, as a result of Bluewater do cause issues at other times that need to be taken into account in any overall capacity and safety assessment. Junctions near schools may have issues for short periods at the end or start of the school day, but not at other times. Congestion at the Lion Roundabout on the A226 in the morning peak is an example of this.

Journey times

26. Appendix 4 contains the table of travel times in Gravesham comparing 2005 with the base 2028 run, whilst Appendix 5 shows some of these graphically. This provides a measure of change in network performance as a result of the proposed levels of development and network improvements, where modelled, for the driver. The routes used are shown in Appendix 6, and enable a more specific analysis of the implications for Gravesham of the proposed development. This needs to be set in the context of the other measures to arrive at an overall picture. The results show

travel times inbound towards the town centre in the morning and outbound in the evening

27. Overall the impact of the land use changes is that in the AM peak, as would be expected, most journeys take longer but not by dramatic amounts except for the route involving Hall Road.

28. In the PM peak there are big increases for that route, Thames Way, Rochester Road and the Town centre one way system. The graph in appendix 5 shows that the area of biggest increase is in the area of Milton Road between Clock Tower and Parrock Street. It is not clear why this is happening as there is no obvious cause and is a matter that needs further investigation. The other graph in Appendix 5 shows an outbound trip along the Rochester Road where the congestion caused by Lion roundabout is evident, as is the impact to a lesser extent of Ordnance Road.

Next steps

29. This is based on the information so far but must be caveated that further work remains to be completed. The picture of the V6 runs is that the results obtained from the earlier modelling exercise remain robust, and the areas of concern previously remain the same ones. Further analysis is required in some areas and consideration of what could be done to improve junctions. Some, like Coldharbour Road on the A227 just north of the A2, have land around that could be used if that was what an appropriate capacity improvement required. Others, like the Pelham Road roundabouts, are surrounded by built development so implementing an capacity improvement may not be possible.

30. Another important caveat is that the model is heavily influence by the scale of development in the wider Ebbsfleet area, and this will need to be monitored to see what the real impacts are as development comes forward.

31. The other implication is that provision for Fastrack and/or conventional bus route improvements is likely to be very important, and the capacity of the system to handle the flows needs to be explored further.

02 November 2012

Appendix 1: Summary of overall results Base case runs

Summary KTS Model results Run Abs Change % Change

Trips Units Period 2005 Base V5 V6 V5 V6 V5 V6

Highway Vph AM 67,365 88,845 83,973 21,495 16,623 31.9% 24.7% Network Vph PM 71,157 98,446 90,371 26,799 18,724 38.4% 27.0% Over capacity V.hours AM 79 783 379 704 300 891.1% 379.7% V.hours PM 158 1,038 1,067 880 909 557.0% 575.3% Average speed Kph AM 61.7 51.7 55.5 -10.0 -6.2 -16.2% -10.0% Kph PM 59.4 49.1 50.8 -10.3 -8.6 -17.3% -14.5% Total travel Kms AM 536,491 750,259 705,290 213,768 168,799 39.8% 31.5% Kms PM 565,816 771,822 754,099 206,006 188,283 36.4% 33.3% Public Trans. Pers.Trips AM 16,850 26,103 24,065 9,253 7,215 54.9% 42.8% Pers.Trips PM 16,776 26,055 24,496 9,279 7,720 55.3% 46.0%

See text for explanation (Version 6 represents the GBC Local Plan development aspirations)

Appendix 2: Junction performance

Ran

king

Junction Typ

e (B

ase

Cas

e)

V6 without mitigation V6 Mitigation run 2005 Base

Ran

king

in 2

010

wor

k

AM PM AM PM AM PM

LOS

Act

ual

Flo

w

LOS

Act

ual

Flo

w

LOS

Act

ual

Flo

w

LOS

Act

ual

Flo

w

LOS

Act

ual

Flo

w

LOS

Act

ual

Flo

w

4 A2 Ebbsfleet C Rbt F 4.762 F – 196 4,862 D 4,341

F - 84 5,581 A 478 A 840 4

5 A2 Ebbsfleet B (see note 2) Rbt E 3,829 F 4,025 B 3,987 D 4,366 B 878 B 1494 13

see note 1 B E

6

A227 Coldharbour Rd/Wrotham Rd Rbt B 3,032 F 3,536 B 3,090 F 3,530 Old A2 junction arrangement 5

7

Hall Rd, Old Perry St and Earl Rd, Gravesend Sig E 2,470 F 2,976 E 2,523 F 2,867 D 1,548 D 2,199 14

9 Pelham Rd S rbt Rbt D 2,228 E 2,535 D 2,245 E 2,474 A 1,483 A 1,516 15

10 Hall Rd Rbt Rbt C 3,510 F – 87 4,426 C 3,466 F -69 4,339 C 3,563 D 3,965 7

Note 1 : The second line is for a junction with dedicated lanes and represents the LOS excluding the dedicated lanes (where the LOS is different). . In 2005 the Ebbsfleet Station was not open.

Note 2 : In the 2010 work Ebbsfleet B was already mitigated as part of the Do-Minimum network

Appendix 3: Junctions

Appendix 4: Journey Times

Journey times 2005 Base 2028 Forecast Absolute change % change

AM inbound / PM outbound AM PM AM PM AM PM AM PM

London Road 04:04 04:17 04:11 04:29 00:07 00:12 3% 5%

Thames Way 05:12 05:34 06:02 06:39 00:50 01:05 16% 19%

Hall Road 05:09 06:11 06:16 07:14 01:07 01:03 22% 17%

Wrotham Road 04:56 04:40 05:01 04:28 00:05 -00:12 2% -4%

Valley Drive 04:06 04:05 04:13 04:16 00:07 00:11 3% 4%

Rochester Road 03:36 03:47 03:42 05:41 00:06 01:54 3% 50%

Old Road E->W 04:48 04:37 05:45 05:08 00:57 00:31 20% 11%

Old Road W->E 04:36 04:37 04:43 05:04 00:07 00:27 3% 10%

Gravesend TC one way system 05:26 04:28 06:38 08:13 01:12 03:45 22% 84%

Routes London Road => Stonebridge Rd roundabout- B2175 - London Rd - New Rd/Darnley Rd/Bath St junc Thames Way => Stonebridge Rd roundabout - A226- Thames Way - New Rd/Darnley Rd/Bath St Hall Road => Hall Rd/Springhead Rd roundabout - Perry Street - Pelham Road - New Rd/Darnley Rd/Bath St junc Wrotham Road => Coldharbour Rd - A227 – One way system

Valley Drive => Marling Cross - Valley Drive - Old Road East Rochester Road => Thong Lane - A226 - Rochester Rd - Harmer St Old Road E->W => Lion roundabout - Old Road East -Old Road West - Pelham Rd roundabout Old Road W->E => Pelham Roundabouts - Old Road West - Old Road East - Lion Roundabout Gravesend TC one way system => complete circuit starting at Bath St/Darnley Rd/New Rd junction

Appendix 5: Selected journey time graphs

Time PM Peak Gravesend One Way system

Darnley Road/Bath Street/New Road

PM A226 Peak Harmer Street to Thong Lane

Appendix 6: Journey times routes