Abstract
In Japan, the number of traffic accidents is increasing every year. Traffic accidents have become serious social problem. Then millimeter-wave radar has got attention as driving safety support system. Since millimeter-wave band has high rectilinear propagation characteristic and strong attenuation characteristic by atmosphere and rainfall scattering, it has remained in use on road with good visibility such as express highway. However, traffic accidents are occurring frequently on road with bad visibility. Automotive millimeter-wave radar has been started in practical application and tends to spread. Application of millimeter-wave radar on road with bad visibility is desired. In this study we examined possibility of millimeter-wave radar on road with bad visibility. We verified experimentally whether ranging by millimeter-wave radar is possible on road with bad visibility. Consequently, at curve inside tunnel, it turned out that ranging to outside of sight can be made possible by reflection of radar wave by wall of tunnel. Possibility of radar on road with bad visibility was found out.
