Traffic simulation

Simulation models provide an ideal laboratory for testing. Simulation evaluation is a cost effective approach to answer what-if questions, and helps reduce the possibility of an adverse or undesirable impact of a new design. Traffic simulation models are used in a wide range of studies by both researchers and practitioners. Examples include the evaluation and design of traffic control and management systems, traveler information systems, study of work zones, impact of new sensor technologies, safety studies, environmental impact studies and testing of new technologies for which no prior operational experience exists.

Modern traffic simulation tools are a very complex synthesis of a number of individual, but interacting, models. These models belong to two categories: models that capture traffic dynamics (such as speed and acceleration, lane changing) and models that capture travel behavior (such as route choice and response to travelers’ information).

We have developed, together with researchers at KTH in Stockholm, a microscopic transit simulation model, busMezzo. On the supply-side, the model represents the public transportation system in detail including the trip lines and stations, timetables, allocation of vehicles and trip chains. The demand for public transportation is represented at different levels of detail up to explicit representation of individual travelers, including models to select routes, choice of transfers and transfer points and the impact of traveler information on these decisions. The movement of transit vehicles in the network is based on flow-dependent travel time models between stops and dwell times at stops that depend on alighting and boarding passengers. This model provides a unique capability to evaluate and support the refinement of planning and operations of transit services, both bus and rail systems.

We have applied traffic simulation models in the areas of intelligent transportation systems, traffic safety, public transportation systems and traffic control.