This paper describes a newly developed computer simulation model, known as SEVQ, for assisting in the evaluation of a wide range of traffic control strategies for motorways. The model has been developed under a contract to the UK department of transport for use in conjunction with the analysis of maintenance options for the Severn bridge but, apart from the current restriction to two-lane motorways, it may be used for other sites and circumstances. The model allows the user to test strategies that either affect stretches of motorways, such as lane closures, speed limits, or overtaking bans, as well as controls at points on a motorway. For the Severn bridge this implied modelling of toll booths, but the concept also extends to control via overhead gantries. Approach roads and access roundabouts are also modelled in the program and it is possible to model complex strategies involving vehicle detectors. The model has been validated from video data collected on the bridge, but it is designed primarily as a tool for testing hypotheses. For example, information on road signing can be input to the model and the user can test the effects of assumptions concerning driver compliance. SEVQ is written in FORTRAN. It incorporates interactive data input and editing, as well as (optionally) providing a schematic moving graphic display on a computer terminal screen of vehicles travelling on the modelled network. Printed output principally concerns vehicle speeds and times on different parts of the network. (a) for the covering abstract of the seminar see IRRD 273510.
Samenvatting