Lane Choice of Diverging Vehicles in Tunnels Adjacent to Downstream Interchanges

Tunnels adjacent to downstream interchanges are the sections with high driving risk on mountainous freeways, but lane-choice behaviors here are unknown. In this study, driving experiments were conducted based on a real vehicle, and vehicle trajectories were obtained in four tunnel-interchange sections. Lane-choice and lane-change behavior of diverging drivers were analyzed. Results show the drivers change lanes in front of and inside the tunnel although crossing the solid lane line is not allowed, but no drivers change to the left lane in the connections between the tunnels and the adjacent interchanges. As the connection length decreases, the share of the drivers changing lanes in Zone 1 and entering the right lane before Zone 5 increases; and the diverging length declines, which leads to increasing maneuver difficulty and diverging risk. Drivers may miss the mainline exit if the connection is too short. The findings can help enhance traffic safety.