Abstract
The Seibu Road runs through the Natural World Heritage area of Yakushima Island, Japan. The volume of traffic and velocity of cars using the road were investigated in February, 1995. During daytime (8:30-17:30), 32 cars used this road on average (range 29-37 cars). One-fourth of them were considered to be tourist traffic. The velocity of cars running along the road was 33km/hr on average (range 21-52km/hr) where the road width was thinnest (4m). Judging from the traffic volume of the road, setting a speed limit for cars of 20km/hr would be sufficient for road safety. Intensive construction work for widening the road width is not required for safety. Moreover, it will greatly damage wildlife and the natural environment of the World Heritage.
