Optimal and Coordinated Control of Urban Expressway Network System

Coordinated ramp metering is an effective method for urban expressway system control. The goal of this paper is to describe an approach to the problem of optimal coordinated ramp metering control in large-scale expressway network system. In this paper, the traffic flow process is macroscopically modeled, and then put forward nonlinear optimal control strategy. Aiming at minimizing the total time spent of all vehicles in the network, the cost criterion is considered the influence of traffic density on neighboring parallel road. The control strategy´s efficiency is demonstrated through applying to two pairs of entrance ramp and exit ramp in a hypothetical expressway. The results of the presented approach are very promising.