The Effect of Sun Glare on Traffic Accidents in Chiba Prefecture, Japan

Abstract

This study aims to clarify the effect of sun glare on traffic accident occurrence. Analyses of traffic accidents were carried out to calculate the position of the sun relative to the first vehicle concerned (i.e., the vehicle most responsible for causing the accident) at the accident time and location by using the traffic accident database of Chiba Prefecture, Japan. The traffic accident rate was found to increase when the viewing angle decreased to less than 90 degrees. When the sun was in front of the first vehicle concerned, there was a higher occurrence of pedestrian accidents, bicycle accidents and accidents at intersections, and a slightly higher occurrence of right-turning accidents and accidents in winter. However, the tendency for vehicle drivers to be affected adversely by sun glare was not observed to increase with increases in vehicle speed. Traffic safety measures against such kinds of accidents are needed.