Evaluation of the Euro NCAP Whiplash Protocol Using Real-World Crash Data

Whiplash injuries account for the vast majority of casualties in road traffic crashes, leading to long-term consequences. The majority occur in rear-ends crashes. Consumer crash tests play an important role in promoting effective concepts to reduce the problem. The current Euro New Car Assessment Program (NCAP) whiplash test protocol includes three sled tests at varying impact speeds and pulse shapes using a BioRID test dummy and 8 measures to assess whiplash potential based on previous best practice. Given the complexity of the test and with more experience, a real-world evaluation of the current protocol was undertaken. Three analyses were undertaken comprising an analysis of test outcome data, a logistic regression analysis, a receiver operating characteristic (ROC) analysis, and a correlation analysis comparing crash and injury outcome. 13,389 drivers reporting whiplash injury symptoms to Folksam Insurance in Sweden were studied, of which 1,266 occurred in cars tested by Euro NCAP. For all occupants reporting initial symptoms, the risk of permanent medical impairment was followed up according to the procedure used by Swedish insurance companies. Test scores according to Euro NCAP, JNCAP and IIWPG protocols were calculated, as well as combinations of the three Euro NCAP pulses. For each combination or protocol, the test score was compared with the real-world outcome. A correlation analysis of the included injury criteria was also performed for the three crash pulses included. The results showed that overall Euro NCAP, Japan New Car Assessment Program (JNCAP) and International Insurance Whiplash Prevention Group (IIWPG) all predict real-world whiplash injury outcome in terms of Permanent Medical Impairment (PMI). Based on limited data available, there was no statistical evidence using logistic regression and ROC analyses that any of the three tests performed better than any other. Correlations between the test scenarios of each of the three protocols, as well as the outcome associations with crash outcomes, suggested consistent improvements in the risk of permanent medical impairment. The main strength of the analyses conducted here was to show the validity of Euro NCAP, JNCAP and IIWPG whiplash test protocols when measured against real-world crash outcomes, which are the most important criteria showing that the tests are appropriately designed to help prevent injuries among the community. Some caution needs to be taken with these findings as many were not statistically significant because of the limited number of cases available. Further evaluation when additional data are available is warranted.