80 underpasses in Japan saw vehicles submerged over past decade: survey

CHIBA, Japan (Kyodo) -- A Kyodo News survey revealed that at least 80 underpasses in the prefectural capitals of Japan have experienced vehicles being submerged in floodwaters over the past decade. The survey, conducted since September, found that these incidents involved 134 vehicles across 33 prefectural capitals. The tragedy was highlighted by two deaths in Chiba Prefecture near Tokyo in August during torrential rain.

Despite the need for infrastructure improvements, both central and local governments have struggled to address the issue. The survey was distributed to the central government, prefectures, and cities managing underpasses in prefectural capitals, with responses received from all 104 managing bodies, covering 866 underpasses in total.

Of these, 415 underpasses, or approximately 48 percent, have warning signs linked to water gauges and other systems installed to prevent vehicles from entering flooded areas. Additionally, 54 underpasses, or about 6 percent, have barriers that can be operated remotely or activate automatically, underscoring the limited physical equipment to block vehicle entry.

Following the August torrential rain in Chiba Prefecture, the Ministry of Land, Infrastructure, Transport and Tourism has begun preemptively restricting traffic at certain locations during heavy rain, urging local governments to adopt similar measures.