As many as 500 railroad crossings in Japan are closed to road traffic for a total of 40 or more minutes an hour during peak train traffic, the Land, Infrastructure and Transport Ministry said Tuesday.

Six crossings in Tokyo were found to remain closed for as long as an hour, while 11 crossings in Tokyo and the cities of Osaka and Yokohama were only open for one minute per hour.

To help street-traffic flow, the ministry said it will undertake such measures as construction of bridges and underpasses for 27 crossings by the end of March, and for another 40 at a later date.

The 500 crossings include 266 in Tokyo, 102 in Osaka and 74 in Kanagawa Prefecture. Eleven other prefectures have crossings with frequently closed bars, the ministry said.