A Comparative Analysis of the Pedestrian Injury Risk Predicted by Mechanical Impactors and Post Mortem Human Surrogates

The objective of this study is to compare the risk of injury to pedestrians involved in vehicle-pedestrian impacts as predicted by two different types of risk assessment tools: the pedestrian subsystem impactors recommended by the European Enhanced Vehicle-Safety Committee (EEVC) and post-mortem human surrogates (PMHS). Seven replicate full-scale vehicle-pedestrian impact tests were performed with PMHS and a mid-sized sedan travelling at 40 km/h. The PMHS were instrumented with six-degree-of-freedom sensor cubes and sensor data were transformed and translated to predict impact kinematics at the head center of gravity, proximal tibiae, and knee joints. Single EEVC WG 17/EuroNCAP adult headform, upper legform and lower legform impactor tests of the same vehicle were selected for comparison based on the proximity of their impact locations to that of the PMHS. The PMHS experienced higher HIC values (1830/2160) and lower impact velocities (8.5/7.5 m/s) than the impactor (1532 and 11.1 m/s) in impacts at the lower fourth of the windshield. The lower legform impactor (31 degrees) and PMHS (right: 25-40 degrees, and left: 24-39 degrees) predicted similar maximum knee bending angles. Some PMHS tibial accelerations (114-613 g) exceeded the proposed acceptance criteria (150-200 g) in both the absence and presence of distal tibial fracture, with the impactor predicting a similar result (335 g). The upper legform impactor test resulted in bending moments (361 Nm) and forces (6.3 kN) exceeding the acceptance criteria, while PMHS sustained pelvic injuries in 6 out of 7 tests.