Modeling impacts of the tunnel section on the mixed traffic flow: A case study of Jiaodong’ao Tunnel in China

Abstract

Modeling impacts of the tunnel section on the mixed traffic flow would be a challenge. It needs to figure out the traffic regulations of the tunnel section that vehicles must comply with. Also it requires depicting the different driving behaviors of cars and trucks when they run into the tunnel. To deal with these problems, we propose a two-lane cellular automaton (CA) traffic model with a tunnel section based on the single-lane CA model proposed by Guzmán (LAI-E model). The asymmetric lane-changing rules with right-lane preference are adopted for trucks, and the symmetrical lane-changing rules are adopted for cars. Especially, the impact of trucks on cars’ driving pattern is taken into account. The drivers’ individual character difference, i.e., cautious and radical, are also considered. The results indicate that the time series of traffic flow, vehicles’ speed in different tunnel sections and trucks’ proportions obtained from the numerical simulation are in good agreement with those obtained from the measured data. The phenomena of the speed fluctuation at the entrance and the exit of the tunnel are reproduced. Besides, the driving pattern of cars’ keeping away from trucks is captured from the spatial–temporal diagrams, and the unbalanced utilization of two lanes, i.e., large usage in the left lane and small usage in the right lane, is revealed. The further simulation indicates that the unbalanced utilization of two lanes will be improved if the trucks’ blocking influence could be neglected. The results will provide a theoretical reference for the optimization of traffic flow in the highway tunnel sections.