Simulation and Experimental Analyses of Microscopic Traffic Characteristics under a Contraflow Strategy

Abstract

Contraflow is a common traffic strategy used to improve the capacity of outbound roads during mass evacuation. Previous studies have focused on the contraflow network configuration, travel time, and number of evacuated vehicles on a macroscopic level. Only a few researchers have considered microscopic factors, such as the contraflow characteristics and moving bottlenecks caused by coaches and trucks. In this study, the effects of the contraflow strategy were investigated through field experiments and traffic simulations. Traffic data were collected from highway segments where trucks were forbidden under regular and contraflow conditions for analysis of the traffic characteristics and the effects of coach moving bottlenecks. The results demonstrate that the capacity and flow speed of contraflow lanes are lower than normal lanes, owing to the narrow cross sections and unfamiliar driving environment. The moving bottlenecks also reduced the speed of passenger car platoons by approximately 5–20 km/h. Four different contraflow schemes were developed and evaluated by Vissim to examine their effectiveness for minimizing the effect of truck moving bottlenecks. The findings revealed an obvious negative effect of trucks on the performance of the contraflow strategy, indicating the need for specific schemes when the truck ratio is large.

Traffic Flow Catastrophe Border Identification for Urban High-density Area Based on Cusp Catastrophe Theory: A Case Study under Sudden Fire Disaster

“…The expected vehicle speed in simulator is setting as 45km/h. As to simulate traffic flow under sudden fire disaster, we use the VISSIM COM and VC++ to restrict the capacity, speed, vehicle routes based on the temporal and spatial distribution influence model under traffic accident in the urban traffic network [29][30][31][32][33][34]. Then, the simulator was performed three times with and without sudden fire disaster respectively.…”

Lexicographically Maximum Contraflow Problem with Vertex Capacities

“…It significantly reduces the total evacuation time and/or increases the number of evacuees sent from the risk zone to safety. Studies show that reversing one lane of a fourlane dual highway increases the evacuation road capacity by approximately 30%, and by reversing all the inbound lanes, it increases by 67% [1]. e contraflow approach is primarily important for emergency evacuations; nonetheless, its applications are not limited to these.…”

“…is is commonly used for accommodating directionally imbalanced traffic associated with daily commuter in big cities as well as consequences due to religious gathering, arrangement of concerts or tournaments, etc. However, there is limited implementation of it in real emergency evacuations due to difficulty in using commonly employed methods to duplicate traffic conditions of real contraflow lane during an emergency [1].…”

Evacuation Contraflow Problems with Not Necessarily Equal Transit Time on Anti-parallel Arcs

“…It significantly reduces the total evacuation time and/or increase the number of evacuees sent from risk zone to safety. Studies show that reversing one lane of a four-lane dual highway increases the evacuation road capacity by approximately 30% and reversing all the inbound lanes, it increases by 67% [1].…”

“…Despite the long history of studies of evacuation problems with contraflow approach, there is limited implementation in real emergency evacuations due to difficulty in using commonly employed methods to duplicate traffic conditions of real contraflow lane during an emergency [1]. However, they have been adapted for evacuating some major metropolitan regions threatened by disasters.…”