ITS MODELLING IN SWEDEN USING CONTRAM

Abstract

The DIRIGENT project to provide real-time driver infromation is particularly focussed on Stockholm and Malmoe, Sweden. Its final project is a graphical Traffic Information and Control (TIC) software system enabling operators to locate and quantify an incident or other blockage on the major road network and select from a set of alternative messaging and control strategies.Traffic modelling requirements, basic methodology, and ITS methodology are outlined. In trials between Lund and Malmoe, the response to variable message signs (VMS) suggesting alternative routes to avoid congestion was 6-41% of drivers. It is suggested that if 30% of drivers responded to the signs, maximum delay is controlled, and that at peak times, a driversion of 10% may be adequate for traffic relief. Wholesale diversion from the congested route is not desired as the capacity of the surrounding road network would be exceeded. In simulation trials in Stockholm, with its landscape of low hills and lakes, alternative route selection is limited by the topography. An incident at Roslagsvaegen was alerted to drivers using VMS, causing traffic to divert west. This eliminated the queue upstream of the sign but queues developed at an important signalised junction. These queues were still cleared more rapidly than would otherwise be the case. The necessity of including demand management policies along with TIC systems is discussed.