Remote-controlled traffic barriers to be installed at flood-prone underpasses

The transport ministry on Tuesday released guidelines related to the installation of remote-controlled traffic barriers at underpasses that are at a high risk of flooding, to restrict access during heavy rain.

The move comes on the heels of a series of deaths at flooded underpasses, including during heavy rain in Chiba Prefecture in August.

“We will promptly take effective measures to prevent accidents in flooded underpasses, in collaboration with relevant organizations,” transport minister Tatsunori Ibayashi told a news conference.

Under the guidelines, compiled for road administrators including local governments, underpasses around the country will be categorized into four levels based on flooding risk, and administrators will determine the classification of each underpass.

The guidelines call for the installation of barriers at underpasses deemed to be at particularly high risk, especially those where flooding has led to casualties or property damage in the past. Traffic will be restricted in advance when weather alerts corresponding to Level 4 emergency warning are issued or when hourly rainfall has reached or is expected to reach a certain level.

The guidelines also stipulate that traffic restrictions and measures to prevent vehicle entry must be put in place when drainage facility abnormalities are detected.