NEXCO CENTRAL Drivers' site


Tunnel entrance

At the entrance to the tunnel, the speed of the car may decrease due to the driver's visibility becoming dark and the driver feeling oppressive.
When one vehicle slows down, the following vehicle attempts to step on the brakes to maintain a safe headway. If this occurs in a situation where there are a large number of passing vehicles, the following vehicles will step on the brakes one after another, causing traffic jams. Similarly, at the exit of the tunnel, speed changes may occur due to changes in brightness, causing traffic jams.

Approximately 13% * 1 of traffic congestion in NEXCO CENTRAL area is caused by tunnel entrances.

  • * 1 Ratio of congestion volume at major congestion points in 2018. However, it does not include traffic congestion caused by the effect of connecting roads. The amount of congestion is an index indicating the size of congestion, and is calculated by congestion time × congestion length.