Stockholm and many other major urban areas suffer from road traffic congestion since capacity expansion of their road networks cannot cope with theincrease of demand. Road traffic authorities therefore make considerable efforts to implement traffic management including Intelligent Traffic Systems (ITS). The Motorway Control SYSTEM (MCS) installed on the E4 motorway through Stockholm is one example of such an undertaking. Although the system has been in operation since the late nineties and is currently being expanded, there is yet no comprehensive knowledge regarding the impacts of the system on traffic safety and performance. The purpose of the paper is to describe a project undertaken at KTH in cooperation with the national and regional road authorities in Stockholm to fill this knowledge gap. The project has included the following activities: Analysis of goals, criteria and strategies for road traffic management in Stockholm. This study shows that the city as well as the Swedish Road Administration have high expectations regarding improvements in travel speed and safety through the use ofMCS. Field studies of traffic performance with and without MCS operation.Due to extensive congestion resulting from bottlenecks the traffic performance on E4 in Stockholm varies with time of day and location. Overall theimpacts on travel time is small and difficult to clearly link to the operation of MCS. Studies of driver behaviour and adaptation to information and control measures from MCS. The purpose of this study has been to observehow drivers respond to VMS recommended speed limits displayed by MCS after automatic incident detection (AID). This has been achieved through videofilming from high observation points, and through mobile observations using specially equipped test cars. The detector and AID logged outputs from MCS have also been analyzed. The results show that the drivers do respond to the speed signs, which have a general "calming effect" on the traffic process. This impact is however small, particularly during congested periods. In a final project stage to be completed in year 2006 the knowledge regarding driver response and behaviour related to MCS operation gathered from the filed studies will be implemented in a microscopic simulation model.This will enable "controlled experiments" for evaluation of system impacts as well as tests of alternative strategies for application of the systemand its operation from the control centre TRAFIK STOCKHOLM. For the covering abstract see ITRD E135582.
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