MITSIM represents road networks with nodes, links, segments, and lanes. It allows the simulation of traffic operations in integrated networks of freeways and urban streets. The data that describes the network is read from a network database file, which can be created using an interactive graphical Road Network Editor (RNE) developed for MITSIM. The network database includes description of all network objects, lane connections, lane-use privilege, regulation of turning movements at intersections (no left-turns, for example), traffic sensors, control devices, and toll plazas.