Research on ramp optimization metering strategy in urban expressway

Taking Beijing urban expressway as research object, the control strategy with the measure of ramp metering is sought to deal with traffic congestion. The ramp metering methods, i.e. the local ramp optimization metering and the congestion dissipation control on urban expressway are put forward. The control strategy is not only to alleviate traffic congestion situation on mainline of urban expressway, but also to avoid the block of the surface streets owing to the serious queue. The examples denote that the methods are feasible and can offer reference for the theory of ramp control, and can be applied to engineering practices.