Present state of traffic accidents

The traffic accident rate in Japan peaked for the first time in 1970, then fell steeply until the late 1970s. Then the rate began to rise again until 11,451 fatalities occurred in 1992. The number of fatalities has fallen since that year, but the number of traffic accidents and people injured by them have both continued to rise, with new records set every year.

Changing Numbers of Traffic Accident Fatalities, Injuries, and Accidents Causing Personal Injury/Death in Recent Years

The following chart shows the state of concentration of accidents based on traffic accident data for the five year period beginning in 1990. It shows that on uninterrupted flow sections, 53.6% of all accidents are concentrated on 9.1% of the total length of all arterial roads, and at intersections, 29.3% of all accidents are concentrated on 6.6% of all intersections on arterial roads. These data show that traffic accidents do not occur with the same frequency everywhere; they occur with higher frequency in certain road sections or at certain intersections.

Traffic accidents vary by location

Research by the Advanced Road Design and Safety Division

Accident Analysis

We believe that to obtain the greatest possible accident reduction effects with limited budgetary resources, it is important that measures be based on scientific and objective surveys of the causes of accidents. The Division’s research mainly analyzes the relationship of traffic accidents with road and traffic conditions to support the enactment of traffic safety measures that can be implemented to reduce the number of traffic accidents caused by factors related to the road environment.

Differences in the accident rate according to presence/absence of center median （note）Accident rate referred to here means the number of accidents per 100 million automobile miles.

（Explanation） 　　This chart is based on an analysis of differences in the accident rate between 4-lane road sections with and without a center strip. It shows that installing a center strip with a width or 1.0 m, or in other words installing a separator between the lanes, is an effective way to lower the accident rate.

Density of Accidents Involving Pedestrians Walking on Uninterrupted Flow Sections

（Explanation） 　　Accidents involving pedestrians are categorized as those occurring while walking along a road and while crossing a road. Pedestrian accidents occurring while the pedestrians are walking along roads in sections with sidewalks and in sections without sidewalks have been compared to study the effectiveness of constructing sidewalks, and it can be concluded that sidewalks are effective in reducing pedestrian accidents in this category.

Surveys of causes of accidents at frequent accident locations

To effectively and efficiently reduce traffic accidents at frequent accident locations, we must accurately answer these two questions. “Why do accidents happen here so often?” “What are the actual differences between frequent accident locations and locations where accidents rarely occur?” The Division is, therefore, performing surveys to support the enactment of effective traffic safety measures by hypothesizing the causes of accidents at locations where they have occurred frequently and performing analyses of each accident cause and of the accident reduction effects of traffic safety measures that have been introduced.