A PROPOSED OPTIMAL REAL-TIME TRAFFIC-RESPONSIVE FREEWAY CONTROL METHODOLOGY

Heavy traffic congestion and excessive delays are making traffic control one of the most critical transportation problems in urban freeways. System-wide optimal ramp control for alleviating congested roads within a freeway system is part of a real-time hierarchical traffic control system. However, the system-wide control systems that are operational are only optimal under steady-state conditions or in a linearized system. Thus, in this research, an enhanced optimal ramp control method for freeway is proposed. This new ramp control strategy is developed by considering not only the volume and occupancy of the main freeway but also the volume on exit ramps and queue length on entrance ramps. This control method employs a continuum traffic flow model to estimate the traffic dynamics in the freeway, and determines optimal ramp metering rates that minimize the total travel time of whole freeway system. For the covering abstract see IRRD E102946.