Lower leg injuries are the most frequent severe injury (AIS/3) to car occupants resulting from frontal impacts. Consequently it is important to be able to detect and quantify the risk of these injuries from car impact tests. The need for a more biofidelic instrumented lower leg and the development of well-founded injury criteria has been clearly identified. At present there are insufficient biomechanical data available to aid the design and construction of such a dummy leg or to define injury risk criteria. Three phases of a research rogramme are reported. In phase one, a driving simulator trial was carried out using 24 subjects to investigate the positioning and bracing of the driver's lower leg prior to an emergecy-braking event. In the second phase of the work, low energy impact tests have been carried out on post mortem human surrogate (PMHS) legs and volunteers. Comparative tests were performed on existing Hybrid III and GM/FTSS dummy feet/ankles. A new method to generate an Achilles force is reported which has been used to enable studies to be carried out into the effect of bracing by plantar flexion, such as emergency braking. Dynamic tests were based on the EEVC foot certification test procedure. The programme included tests to produce inversion and eversion. Additional toe impact tests were performed to assess lower leg behaviour with pre-impact bracing, allowing for future comparisons with the ALEx leg. Difficulties inherent in the interpretation of PMHS testing are reviewed and comparisons between tests on PMHS subjects and human volunteers are presented. The final part of the paper reports the findings of an in-depth retrospective accident analysis based on data in the UK Co-operative Crash Injury Study database. (A)
Abstract