The focus of this report is on the head testing component of pedestrian impact testing. Current pedestrian testing protocols evaluate vehicle performance at a single crash speed. Vehicles that perform well at the test speed may perform poorly at a slightly higher test speed if there is minimal clearance between the bonnet and harder structures beneath. Measurement of this clearance may aid in giving the vehicle a more appropriate assessment. In previous work, a method has been developed for evaluating performance across a range of speeds, taking account of underbonnet clearance. In this report, a new practical methodology is presented for measuring underbonnet clearance, by drilling holes in the outer surface of the bonnet. This method was used to measure underbonnet clearance for 64 test locations on five vehicles tested by the Australasian New Car Assessment Program, and the resulting clearance measurements were used to evaluate each vehicle. This evaluation took into account the result from the original test, the clearance measurements, the distribution of speeds in real pedestrian crashes, and a function for predicting fatal head injury risk from Head Injury Criterion values. The resulting evaluations showed that knowledge of the underbonnet clearance measurements affected the evaluation of specific individual test locations and could potentially affect the overall evaluation of each vehicle. The clearance measurements may also be of use in monitoring performance, encouraging safer designs and in other evaluation schemes that were not considered. (Author/publisher)
Abstract