Today, the number of traffic accident fatalities in Japan exceeds 10,000 a year, of which approximately 30% involves pedestrians. From the standpoint of social cost alone, it is necessary to reduce not only fatalities but also injuries that require long periods of rehabilitation. One approach to pedestrian protection might be the prevention of accidents through the improvement of road conditions and the education of drivers and the other road users.

This report will first introduce the statistical data on pedestrian accidents in Japan, with emphasis on the high frequency of head and leg injuries and the high percentage of pedestrians who are hit from the side by vehicles. Further, this report describes leg impactor tests carried out by J ARl/ JAMA as part of our pedestrian protection studies. Specifically, these tests were aimed at (l) determining the influence of upper body mass on leg impact and (2) comparing the indirect measuring method (the knee- angle-measuring method) and the direct measuring method (the force-measuring method). The vehicle frontal shape in terms of bumper height, bumper lead, and hood edge height was used as the main parameter.

Results indicated:​ (1) The presence or absence of an upper body mass did not affect tendencies of varied measurement values, except for knee tensile force. Although absolute values of knee tensile force and knee angle were affected by upper body mass, it was believed that the addition of an upper body mass is not an imperative test condition. (2) Among the leg impactor measured items, knee angle (dynamic deformation angle) and force (bending moment and shearing force) indicated different responses to the parameter under certain conditions. Therefore, it is judged inappropriate to consider knee angle and force as identical evaluation criteria. For the leg protection, however, there is no adequate index to be applied to the criteria except the knee angles and forces In the future, it will be necessary to confirm which impact conditions affect leg injuries by means of validation tests (e.g., accident reconstruction test, cadaver test). And, it will be also necessary to study the correlation between leg injuries in actual accidents and the test results in order to clarify for the effective leg injury criteria.