SIRIUS (Systeme d'Information Routiere Intelligible aux Usagers) is the largest urban field operational test of the advanced traveler information and automated traffic management system in Europe. With variable message signs, SIRIUS has been in operation in the Paris region since December 1992. This study is a preliminary investigation of the effectiveness of the SIRIUS system in traffic management. The concern of the paper is the extent to which motorists responded to real-time traffic information and the consequential changes in link flow under SIRIUS. Time-series traffic data were analyzed to evaluate cumulative arrival patterns at a selected link. The study suggests that there is evidence indicating variable message signs influenced drivers to take the less congested route. The cumulative arrival curves also suggest that diversion behavior is closely associated with the information about the level of congestion. The heavier the congestion the greater the motorists' response to the messages and this relationship is exponential. (A)
Abstract