Expanded Preventive Traffic Restrictions on Direct National Road Underpasses
Overview
In light of continued heavy rain across Japan since the August 2026 Chiba heavy rain event, the Ministry of Land, Infrastructure, Transport and Tourism will expand the introduction of preventive advance traffic restrictions at underpasses on direct national roads. Fifteen new sites will be added, bringing the nationwide total to 22 sites. Restriction criteria will be established based on disaster weather information and hourly rainfall, with details to be announced later by each Regional Development Bureau.
Key points
- The introduction of preventive advance traffic restrictions will be expanded at underpasses on direct national roads.
- Fifteen new sites will be added, bringing the total to 22 sites.
- Restriction criteria will be established based on disaster weather information and hourly rainfall.
Overview
In light of continued heavy rain across Japan since the August 2026 Chiba heavy rain event, the Ministry of Land, Infrastructure, Transport and Tourism decided to expand the introduction of preventive advance traffic restrictions for underpasses on direct national roads.
The operation, for which introduction has been pursued at seven sites nationwide, will be expanded by adding new sites based on flooding records and other factors, bringing the nationwide total to 22 sites.
Impact
During the August 2026 Chiba heavy rain event, flooding at an underpass caused casualties and other damage. The introduction of these restrictions is intended to prevent similar flooding accidents during future heavy rain events.
Details
The covered locations are underpasses on direct national roads nationwide, including the National Route 16 Muratamachi Underpass.
Restriction criteria are to be established based on disaster weather information and hourly rainfall.
Details of the restriction criteria will be announced later by the respective Regional Development Bureaus. The locations covered by the expansion are listed in a separate document.