Maidstone Joint Transportation Board 04/11/15

Urgent Update

This urgent update supplements the previously submitted paper entitled ‘Results of the VISUM Transport Modelling’ and addresses the key issues discussed at the meeting of 28th October, at which Amey attended to give a full briefing on the outcomes of the latest modelling. In particular this paper provides additional clarity on the issues of severity of impact and scheme funding sources.  

Severity of Impact

The presentation given by Amey enabled the results of the ‘2031 Do Something 4’ (DS4) scenario to be compared and contrasted against the previously modelled scenarios. The results for DS4 were presented in the form of two model runs that were identical aside from being with (DS4a) and without (DS44b) the Leeds-Langley Link Road.

The DS4 modelling has enabled the changes in travel demand that could occur as a result of the planned growth in housing and employment over the period to 2031 to be identified, taking account of the transport interventions associated with bus frequencies, walking/cycling mode shift and parking costs identified at the meeting of this board on 22nd July 2015.

Table 1 summarises the travel demand in terms of vehicle movements for each scenario and quantifies the change when compared against the 2014 baseline.

Table 1: Travel Demand (AM Peak)




2031 DS1









Vehicle Trips








% difference vs 2014








When compared against the 2014 baseline, the results identify an increase of 11% in vehicle trips for the DS4 scenario both with and without the Leeds-Langley Link Road. This falls below the 17% increase that had previously been predicted for the ‘Do Minimum’ scenario, due to the positive effects of the transport interventions associated with bus frequencies, walking/cycling mode shift and parking costs.   

The 11% increase takes account of the changes in travel behaviour that could be expected to occur as a result of the interventions and must therefore be viewed as the residual cumulative impact of the proposed housing and employment growth on the highway network. Importantly, the 11% should also be regarded as headline figure that masks the significant geographical differences associated with the distribution of development and the implications this has on individual parts of the highway network.

When assessing the residual cumulative impact of growth due regard must be given to paragraph 32 of the National Planning Policy Framework (NPPF). This advises that:

Plans and decisions should take account of whether:

·         the opportunities for sustainable transport modes have been taken up depending on the nature and location of the site, to reduce the need for major transport infrastructure;

·         safe and suitable access to the site can be achieved for all people; and

·         improvements can be undertaken within the transport network that cost effectively limit the significant impacts of the development. Development should only be prevented or refused on transport grounds where the residual cumulative impacts of development are severe. 

The 11% increase is equivalent to an additional 3,800 vehicle trips on the highway network in the AM peak. The effect of these additional vehicle trips would be to place further strain on the highway network, with those areas that are currently congested worst affected.

The distribution strategy adopted by the Borough Council in the emerging Local Plan will result in a high concentration of additional vehicle trips in south and south eastern Maidstone. This part of the network, in particular the A229 and A274 corridors, already suffers from extensive queuing and delays over prolonged periods. 

At the request of the County Council, Amey were asked to interrogate the DS4 model runs to provide a fuller understanding of the impacts that could occur on these road corridors.

Table 2 presents the comparable vehicle trips for the 2014 baseline, Do Minimum and DS4 scenarios. 

Table 2: A229/A274 Vehicle Trips


AM Peak

 2 way flow






 DS4A (with LLLR)

 DS4B (without LLLR)

A229 Loose Rd





% difference vs 2014





A274 Sutton Rd





% difference vs 2014






It can be seen that the DS4 scenario will result in vehicle trip increases of up to 22% on the A229 and up to 45% on the A274 when compared against 2014 levels. This magnitude of change is well above the global increase of 11%, thereby demonstrating how these already congested corridors will be worst affected by the planned distribution of housing and employment.

The analysis reaffirms the County Council’s view that the residual cumulative impact of the additional vehicle trips on south and south eastern Maidstone will have an unacceptably severe impact.

Scheme Funding

The deliverability of the transport interventions underpinning DS4 is dependent on the mechanisms available to secure funding. There are uncertainties surrounding potential improvements to bus service frequencies, which will require further dialogue with operators to confirm how the needs of housing and employment growth can be aligned with commercial priorities.     

At the meeting of this Board on 14 October 2015, indicative cost estimates were provided in relation to the previously agreed package of highway improvement schemes. Funding has already been secured towards several individual schemes, as summarised in Table 3.  

Table 3: Funding Sources

Highway Improvement

Estimated Cost*

Funding Secured?

Funding Sources

Bridges Gyratory



Local Growth Fund (£4,600,000)

Maidstone Borough Council (£1,140,000)

A20/M20 Junction 5




A229/A274 Wheatsheaf



Local Growth Fund

A20/Willington Street




A274/Willington Street & A274/Wallis Avenue




A20/Hermitage Lane




A20/Coldharbour Lane




A249/Bearsted Road & Bearsted Road/New Cut




A26/Fountain Lane




Leeds-Langley Link Road




*Excludes statutory undertakings and potential land acquisition

Most of the highway improvements identified in Table 3 offer scope for funding through Section 106 Agreements secured from new development and the Local Growth Fund, where £8.9m has been allocated to the Maidstone Integrated Transport Strategy. The exceptions are the Leeds-Langley Link Road and Bearsted Road improvements, which currently have no identifiable funding sources and will require further work to test cost assumptions and confirm feasibility.