This paper reports on the development of a new legform to test contact sensors of active safety systems that could be used to deploy pedestrian protection systems. To test the systems accurately a test tool is required with properties that are as close as possible to human responses. Current legforms were not designed to test sensors, but were designed to assess passive protection by imparting a concentrated force to selected parts of the vehicle. Due to the characteristics of the legform it is believed that the bumper sensor threshold could be set too high, causing a late deployment or even preventing the active system from deploying. The possibility of serious or life threatening head injuries occurring could be increased if the active system does not deploy as intended.

To achieve a better force distribution on the bumper sensors, the revised impactor needs to be as biofidelic as possible. Data on the mechanical properties of human bone and flesh have been researched and materials selected to provide the most realistic response during a vehicle to pedestrian impact. The purpose of the impactor is to assess contact sensor technology that could be used in active safety pedestrian systems to distinguish an impact between a vehicle and a pedestrian and a vehicle and another object. The paper reviews the legform design specification in terms of its requirements and biofidelity data. Through finite element modelling, the use and limits of the test tool with regard to bumper reference height and the use of an upper body mass are discussed.