TransModeler is a versatile traffic simulator with many advanced features including support for key aspects of Intelligent Transportation Systems. TransModeler simulates a wide variety of facility types, including mixed urban and freeway networks, and is easily customized for modeling specific geographic areas such as downtowns, highway corridors, or beltways.
TransModeler simulates toll plaza operations with various payment methods. Easily modified service time parameters allow you to model any type of toll payment technology including electronic toll collection facilities.
When used as a microscopic simulator, TransModeler simulates the behavior of each vehicle every one-tenth of a second. Vehicles can vary in terms of their physical and performance characteristics, and can be custom defined by users. Acceleration, deceleration, car-following, lane-changing, merging/yielding, and movements at intersections are simulated in detail and are affected by driver aggressiveness, vehicle characteristics, and road geometry. While default settings are provided for important behavioral models, users can easily change the parameters of these models.
Unlike older simulators that require turning movements as inputs, TransModeler can also determine vehicle routes using dynamic traffic assignment of origin-destination trip tables. Travel times by time period and network segment can be input from external data or developed by running traffic assignments and traffic simulations. Vehicle paths can also be input from external files including those generated by TransCAD and/or created or edited by analysts. When unexpected delays occur, some drivers will change their routes during their trips. This can be in response to message signs or to unexpectedly high levels of congestion.
TransModeler can also simulate wide area networks at varying levels of fidelity and with different simulation methods. TransModeler includes mesoscopic and macroscopic simulators in addition to its microscopic simulator. In the mesoscopic simulator, vehicles are collected into traffic cells and streams and their movements are based upon predefined capacities and speed-density functions. Individual vehicles are tracked, but vehicle movements use aggregated speed-density functions rather than car-following and lane-changing logic. In the macroscopic simulator, vehicle movements are based upon volume delay functions that depend upon the functional class of the road system. The operation of traffic signals is not modeled explicitly in mesoscopic and macroscopic simulation. Rather, signal timing plans are converted into equivalent capacities for turning movements. Capacity constraints and queue spillbacks are examined before vehicles enter and exit segments, so that queues will form when capacity is not available downstream. A time-based approach is still used, but the time steps do not need to be as fine-grained in these simulation modes.
TransModeler is unique
in that it provides a hybrid simulation capability in which high fidelity
microsimulation can be intermixed at will with mesoscopic and macroscopic
simulation on any network segments. Portions of the network of greatest
interest can be simulated with microsimulation and other portions can be
simulated with less detailed methods. This hybrid capability makes it
possible to simulate very large networks with modest computing power.
