Optimal Signal Control in Urban Road Networks with High Priority Congested Centers

Keeping the density of traffic flow and air pollution in an acceptable level and developing a goodcapacity for transit in the high priority areas of the city, is really a big deal in large and crowdedcities. to address this problem, a new method of intersection signal optimization is presented inthis paper. based on network fundamental diagrams, an internal–external traffic metering strategy(ietms) is developed for controlling density of traffic in high priority areas globally. protectingthe network from gridlock, optimizing the queue ratios in entrance arterials and utilizing thereserved capacity are the main objectives of the problem. the methods of mixed integer linearprogramming and quadratic programming are used for solving the problem. a traffic simulatorsoftware (vissim) has been used for simulation in which the coded program is developed invissim-com interface. finally the model is applied in a part of urban network of tehran, iran.the results show that redistributing of traffic density in the whole network and protecting highdensity areas from gridlock can efficiently improve traffic flow measurement in high priority areas.