NEXCO CENTRAL Drivers' site


Sag and In-bound Sakabe

Car while driving sag ※ 1 and In-bound and reaches the hill, there is a car that speed in less notice will fall. When the vehicle in front slows down, the following vehicles try to brake and maintain a safe headway. If this occurs in a situation where there are many traffic vehicles, the following vehicles will step on the brakes one after another, causing congestion.

NEXCO CENTRAL about 57% of the traffic concentration congestion that occurs in the tube ※ 2 is, sag and In-bound is the congestion that slope is caused by.

  • ※ 1 Out-bound from the hill In-bound part of change in slope.
  • * 2 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.