This study analyses theoretical flow patterns of the Dynamic System Optimum (DSO) assignment and proposes the ramp control strategy toward DSO using a simple network of a parallel pair of an expressway and a surface street. The marginal cost for the dynamic traffic flow is first defined in contrast with one in static analysis. An analysis on DSO based upon the dynamic marginal cost suggests that the best strategy for DSO is to assign demand onto the faster route (the expressway) just up to its capacity. Then, assuming each traveller chooses a route so as to minimise his/her own travel time, it is shown that a ramp control such as metering can decrease the total travel time of not only the expressway but also the surface street. Finally, the proposed ramp control strategy is applied to the existing traffic conditions.
Samenvatting