Active Traffic Control for Oversaturated Intersection Group in Emergency Evacuation

Abstract

In the emergency evacuation condition of an urban road network, desmic traffic congestion phenomenon may appear in grouped intersections. Aimed at achieving reasonable distribution and orderly operation of evacuation flow, this paper came up with an active traffic control method of congestion prevention in response to oversaturated intersections' traffic tide. First, the authors predict oversaturated intersections' traffic tide based on traffic flow which is calculated using the user equilibrium dynamic traffic assignment model (UE-DTA). Second, based on traffic flow calculated from system optimal dynamic traffic assignment model (SO-DTA), they find critical congestion routes that may cause desmic traffic congestion of grouped intersections, and select the recommended bypass routes which can be used to receive partial traffic flow from critical congestion routes. Third, they take the minimal gap between expected network traffic and system optimal traffic as an objective to calculate the optimal pre-diversion volumes from critical congestion routes to recommended bypass routes in the short term. Developing trend of oversaturated intersection group can be reserved via the active diversion of congestion routes' flow in advance.