Development of expressway traffic control algorithm based on quadratic programming

摘要

The chronic traffic congestion in urban areas has become a problem in recent years, and the ITS industry is considering various ways to reduce traffic congestion from the standpoints of safety and smooth traffic flow. The ramps of urban expressways are closed during times of excessive traffic based on the judgement of road management personnel, but thorough and efficient traffic control is not always accomplished. There is a need for a more advanced control means that provides dynamic estimations and predictions of both the traffic flow on expressways and the demand for the use of expressways. This report proposes two algorithms for controlling the traffic inflow on ramps in real time and evaluates the algorithms using a simple simulation. The first algorithm targets times when there is no traffic congestion and determines the ramp inflow using linear programming. The second algorithm assumes there is traffic congestion and determines the ramp inflow using quadratic programming. With the first algorithm, the inflow almost stops when the number of vehicles becomes large. With the second algorithm, however, ramp congestion tends to be relieved because the inflow is controlled in such a manner that the number of stagnant vehicles does not exceed an