In SIMLAB a microscopic traffic simulator (MITSIM) is developed to model the traffic in the network and represent the ``real world''. In MITSIM the traffic flow and network elements are represented at a level of detail sufficient to capture the sensitivity of vehicular flow to real-time control and route guidance and to simulate the surveillance system that supports dynamic traffic management. The model is designed to replicate traffic flow as accurately as possible. The main elements of MITSIM and their characteristics are outlined below. Technical details are presented in Chapter 3.