Dynamic Ramp Control Strategies for Risk Averse System Optimal Assignment

This paper explores dynamic ramp control strategies for a simple transportation network with stochastic travel time. The objective of ramp metering considered in this paper is not only to mitigate congestion in a freeway but also to achieve Dynamic System Optimal (DSO) assignment in a network with two parallel links; on of the links is a freeway with a single bottleneck, and the other is a local bypass that can be regarded as an aggregation of a local street network. Travel time on the bypass link is assumed to follow a stochastic process because of many factors that cannot be controlled or predicted. A road network manager is expected to control the inflow rate to the freeway at each time point so as to attain the DSO assignment for a certain time period.