A Study on Problems of Safety Management in Cherry Trees on A Street of the Tokyo Prefectural Road by an Analysis of Traces of a Collision with a Car and a State of Management

Abstract

We aimed at clarifying problems of safety management in roadside trees on A street of the Tokyo prefectural road in Japan. We investigated and analyzed the data in connection with an accident by a collision between a roadside tree and a car and cherry roadside trees on the street where a lot of such accidents occurred on that data. As the result, it became clear that there was a big difference in the number of accidents between the results of the data analysis and the site investigation, so that the road administrator was not able to understand the occurrence of the accident enough. And on A street, trunks and branches of trees that incline to the roadway side and that distance to the roadway is short are big traffic obstacles. It is important for the prevention of such accidents to cut thin branches expected to become a traffic obstacles in the future as soon as possible and to correct a tree form because the group that the diameter of the pruned branch was larger tended to have more individuals that the prune sign was decayed.