Footrest Design to Reduce Lower Leg Injury in Frontal Crashes

The frontal impact is the most common vehicle crash type in accidents involving cars. During a vehicle frontal impact, the injuries are caused by occupant body moving forward and impacting the vehicle interior parts. The performance of the vehicle body and the interior parts design may influence on the occupant injury levels. Injuries in the occupant lower body are usually affected by the vehicle lower body deformation and the design of the interior lower parts (lower instrument panel, pedals, floor and footrest). When the purpose is to reduce the injury of a specific body region, the modification of the interior part design can be more effective in terms of impacts in mass, costs and development time than a modification in the vehicle body. The objective of the study was to develop a new footrest design to reduce the injury level of the left driver leg in a frontal crash condition. It was also evaluated the influence of the vehicle body deformation on the driver leg injury. There were manufactured footrest prototypes with different shapes and materials to check the influence on the leg injury. There were performed physical sled tests to evaluate the performance of different parts designs. The tests shown an average of 40% reduction in the leg injury with the new parts. The influence on the footrest usability (comfort) with the different shapes and materials was also considered. It was possible to reduce the injury to required levels and keep footrest comfort at acceptable levels. The best solution meet the safety, comfort and costs targets to allow parts regular production.