Center for Traffic Simulation Studies

While traffic network simulation has a vast literature, most studies have focused on the simulation of automobile traffic. There has been little research on the simulation of transit, emergency, and commercial vehicle fleets in the network. While these modes have distinctly different route and service characteristics, they may interact with automobile traffic either at the supply level through shared right of way and network control scheme or at the demand level in terms of mode split. Operational planning of real-time schemes for emergency or commercial use also requires modeling methods that properly capture the network supply dynamics; thus, this must be done in conjunction with auto traffic simulation. With enhanced computational capabilities and the availability of detailed commercial and public domain software, practitioners' use of simulation for the design and analysis of urban networks is becoming a more viable option. Further research into improving fundamental auto traffic simulation models is also being undertaken by agencies and researchers. How comprehensive urban network simulation environments will be, however, is influenced by their capability to handle multiple vehicle classes. This paper focuses on the issues that arise, classifies the simulation and contextual options, discusses the associated modeling requirements and suggests schemes to develop environments that can comprehensively model networks with a complete mix of various vehicle classes. The paper includes a discussion of the state of the art of urban traffic network simulation, encouraging deeper examination of the complexities involved in using simulation as a comprehensive tool for urban network analysis.