Cellular Automata–Based Model for Simulating Vehicular–Pedestrian Mixed Flows in a Congested Network

In the design of evacuation plans for major metropolises, one ought to recognize that a potentially large number of evacuees either depend on transit or other modes or need to walk over a long distance to reach their cars. In the process of approaching some designated pickup points or intermediate destinations, the massive number of pedestrians may present a tremendous burden to vehicles in the roadway network. Hence, development of a simulation tool capable of replicating realistic traffic conditions by both the pedestrian and the vehicle flows in the chaotic situation is imperative. Such a simulation tool should account for interactions or conflicts between pedestrians, between vehicles, and between pedestrians and vehicles. Despite the increasing use of traffic simulation as the primary analysis tool, effective software to simulate the mixed vehicle–pedestrian flows in congested environments remains in its infancy. This study attempts to address this need with the mixed cellular automata method. The proposed simulation model has integrated the strengths of the cellular automata method with some probabilistic functions, and offers a realistic mechanism to reflect the competing and conflicting interactions between vehicle and pedestrian flows. Although the model development remains in a preliminary stage, the experimental results indicate that failure to account for the impact of mixed-flow interactions in a congested traffic system could result in significant underestimates of the resulting delay, travel time, and system throughput.