Simultra
Multiagent simulator of road traffic in Qt/C++ and OpenStreetMap.
...It combines microscopic and mesoscopic simulations into one multiagent hybrid simulator. The large-scale maps are modelled mesoscopically in real-time, and the complex traffic interactions benefit from detailed agent-based microscopic simulations. To resolve the concurrency issues within the maps representation and the meso-micro transitions, Simultra combines an event-based mesoscopic model of the maps with a more detailed physical engine.