MICROSCOPIC TRAFFIC SIMULATION PACKAGE FOR ISOLATED INTERSECTIONS

The Center for Highway Research at the University of Texas as Austin has developed a new microscopic traffic simulation package, called the traffic experimental and analytical simulation (TEXAS) model, that can be used to evaluate existing or proposed intersection designs and to assess the effects on traffic operations of changes in roadway geometry, driver and vehicle characteristics, flow conditions, intersection control, lane control, and signal timing plans. A geometry processor calculates vehicle paths on the approaches and in the intersection, identifies points of conflict between intersection paths, and determines minimum available sight distance along each inbound approach. A driver-vehicle processor generates individual driver-vehicle units and describes their characteristics. An auxiliary headway distribution analysis processor helps select an oppropriate headway distribution. A simulation processor simulates the movement of each driver-vehicle unit through the system and gathers performance statistics. Linear acceleration and deceleration models and a noninteger, microscopic, generalized car-following equation are used. Traffic signal simulators are included for pretimed, semi-actuated, and fully actuated controls. Other intersection control options include no control and yield, less-than-all-way stop, and all-way stop signs. New simulation techniques include lane change decision and geometry, sight distance restriction checking, intersection conflict checking, and storage management and logic processing methods. A new field device for recording validation data and for determining suitable model input is described. Input was designed to be user oriented and minimal; output is concise and functional. Documentation has been developed for both users and programmers. /Author/