The Gifu Prefectural Government submitted to the prefectural assembly Thursday an ordinance calling for an environmental conservation tax on buses and taxis that use the nation's highest highway, on Mount Norikura, in the Japan Alps National Park.

The local government hopes to impose the tax, the first levy to protect the environment of a national park, in May if it is approved by the assembly and endorsed by the national government, prefectural officials said.

The prefecture envisions collecting 30 million yen a year, which would go toward research on rare grouse in the area and financing nature guides and environment patrols, they said.

The tax would range from 1,500 yen to 3,000 yen for buses and 300 yen for taxis. Personal vehicles would be banned from the Norikura Skyline highway starting in May.

The highway will be toll-free from May because tolls collected so far have redeemed its construction costs. Some 210,000 vehicles have used the road annually during its open periods, from May 15 to Oct. 31.

Opened in 1973, the highway is about 2,700 meters above sea level along the 3,026-meter mountain on the border of Gifu and Nagano prefectures.