Abstract
Control measures and strategies can be used to counter traffic congestion in urban road and freeway networks. This congestion could otherwise lead to a strong degradation of the network infrastructure and accordingly reduced throughput. The primary reasons for infrastructure deterioration due to traffic congestion are explained. A comprehensive overview of proposed and implemented control strategies then is provided for three areas: urban road networks, freeway networks, and route guidance. Selected application results, obtained from either simulation studies or field implementations, are briefly outlined to illustrate the impact of various control actions and strategies. Directions for further research are discussed.