Simulation-based assessment of variable message signs route guidance information under congestion condition

The benefits of the route guidance information from variable message signs (VMS) and the congestion shifting phenomenon owing to the inappropriate offering of route guidance information were discussed using the simulation software, VISSIM. The important conclusions are; (1) the location of VMS has great impacts on the effect of the route guidance information. If VMS route guidance information is disseminated appropriately, the performance improvement of the road network could be up to 23.7% (delay reduction), 31.8% (accumulated stop time reduction) and 38.7% (stop frequency reduction). (2) The performance improvement of the road network depends on the quality of the recommended alternative route. If the alternative route quality is not satisfying, the congested area would not be ameliorated but deteriorated and new congestion would be produced at the alternative route. (3) The frequency of the left turns and their capacity are two critical factors signifying the quality of the alternatives. This implies that the criteria should include the frequency of the left turns and their capacity besides travel time, travel distance and so on when the alternatives are selected.