Modelling of Dynamic Hard Shoulder Running in the National Transport Model
M Jay, Department for Transport, UK
This paper describes how Dynamic Hard Shoulder Running has been modelled in the UK National Transport Model, reporting results of the business cases for such schemes and for a wider £6bn roads investment programme.
Following from the success of a trial section of HSR on the Motorway network near Birmingham, the UK Department for Transport announced in October 2007 that the Department would perform a feasibility study of the ?potential for installing advanced signalling and traffic management systems on a wider scale, across the strategic road network?, to be published in the spring of 2008.
Due to its geographic scope The Department?s National Transport Model was selected as being suitable to undertake such strategic modelling work however; in order to allow the modelling of dynamic HSR some bespoke development effort was required. The requirement involved providing dynamic increases to the capacity of individual links to mimic the impact of HSR activation during individual time periods, in response to forecast increases in demand. The increases in capacity were also linked to a special HSR speed flow curve which limited traffic speeds to 60mph during periods of HSR activation.
Following the successful completion of this up-grade the NTM was used to analyse a number of capacity enhancement scenarios and produce a business case for extending the use of HSR across over 400km of the English Motorway network. The results of the feasibility study were published in March 2008.
Since then the Department has been developing a more detailed programme for the rollout of HSR across the Motorway network and this resulted in the announcement in, January 2009, of a programme of investment of up to £6 billion. This includes plans for the provision of over 550 Lane Km of capacity through the use of dynamic Hard Shoulder Running.
This paper first discusses how dynamic HSR is modelled in the NTM, including details of the capacity and speed flow assumptions used. It then describes the methods used to generate a programme of schemes and the key messages and results of the feasibility study. Finally, it presents traffic, congestion and CO2 results from the analysis performed earlier this year comparing HSR with conventional widening on the announced major schemes programme.
Association for European Transport