VISTA includes a flexible dynamic traffic assignment module. Our DTA model can solve for both User Equilibrium and System Optimal constraints.

Our Dynamic User Equilibrium implementation searches for assignments that place as much demand as possible on least-cost routes. While travel time is generally used as the cost, any other cost metric may be substituted. This method has been developed over a number of years and used successfully in multiple projects.

Our System Optimal implementation searches for assignments that place as much demand as possible on routes so that the overall performance of the network is improved. Again, travel time is the most commonly used cost, though other cost metrics may be used. This method has been developed more recently, and will be included in VISTA soon.
The assignment module recognizes multiple vehicles classes, class-based roadway restrictions, closures, and controls. Currently, all vehicles are departure-time based.

Ongoing development will add arrival-time based trips, multi-destination trips, and intermodal trips.