Updated correlation of results from the Australian New Car Assessment Program with real crash data from 1987 to 1996

Monash University Accident Research Centre – Report #152 - 1999

Authors: S.V. Newstead & M.H. Cameron

Full report in .pdf format [1.4MB]

Abstract:

A number of ongoing major initiatives have been established to assess relative vehicle occupant protection performance for consumer information. Two of these initiatives are the Australian New Car Assessment Program (ANCAP) and the Used Car Safety Ratings (also known as Vehicle Crashworthiness Ratings and Driver Protection Ratings). The first of these estimates the relative occupant safety of current model vehicles by measuring dummy responses in controlled crash testing. The second initiative estimates the relative risk of severe driver injury for individual models of vehicles involved in real crashes by examining mass crash data. A study by Newstead and Cameron (1997) has examined the relationship between the results from these two programs. The broad aim of this project was to further assess the relationships between the results of these two programs using more current data and covering a wider range of vehicle models.

The results of correlation of ANCAP test results with real crash outcomes as measured by crashworthiness ratings suggest a number of relationships. Firstly, whilst the results from full frontal ANCAP testing have some association with real crash outcomes, the associations between offset ANCAP testing and real crashes are much stronger. The ANCAP test results and their associated measures have strong association with both the injury risk and injury severity components of the crashworthiness rating when considering all crash types, and with the injury severity component of crashworthiness rating when considering two-car head-on crashes. Correlations were generally stronger between ANCAP results and two-car head-on crashes than with all crash types but this difference was not large. Mass adjustment of the ANCAP probability measures also improved their relationship with real crash outcomes. Detailed analysis of injury data by body region generally confirmed the results of the correlation analysis using a more detailed and specific method of analysis.

Logistic regression models of crashworthiness ratings and its components as a function of ANCAP measures were built, providing a direct functional relationship between the two programs as compatible and consistent measures of relative vehicle occupant protection.

Executive Summary

Motor vehicle occupant protection continues to be a growing issue not only for Government authorities concerned with road safety, but also for motor vehicle consumers and manufacturers. A number of ongoing major initiatives have been established to assess relative vehicle occupant protection performance for consumer information. Two of these initiatives are the Australian New Car Assessment Program (ANCAP) and the Used Car Safety Ratings (also known as Vehicle Crashworthiness Ratings and Driver Protection Ratings). The first of these estimates the relative occupant safety of current model vehicles by measuring dummy responses in controlled crash testing. The second initiative estimates the relative risk of severe driver injury for individual models of vehicles involved in real crashes by examining mass crash data.

A study by Newstead and Cameron (1997) has examined the relationship between the results from these two programs. The broad aim of this project was to further assess the relationships between the results of these two programs using more current data covering a wider range of vehicle models whose relative occupant protection has been assessed in both programs. Comparison has been made using the most currently available crashworthiness ratings based on all crash types, limited crashworthiness ratings derived from crashes of specific types, and modelling of crash outcomes as a function of ANCAP test results. A second stage of the project examined the relationship between injuries recorded in Transport Accident Commission claim data and the corresponding measurements taken from the crash test dummies in the ANCAP test procedures.

The results of correlation of ANCAP test results with real crash outcomes as measured by crashworthiness ratings suggest a number of relationships. Firstly, whilst the results from full frontal ANCAP testing have some association with real crash outcomes, the associations between offset ANCAP testing and real crashes are much stronger. The ANCAP test results and their associated measures have strong association with both the injury risk and injury severity components of the crashworthiness rating when considering all crash types, and with the injury severity component of crashworthiness rating when considering two-car head-on crashes. Correlations were generally stronger between ANCAP results and two-car head-on crashes than with all crash types but this difference was not large. Mass adjustment of the ANCAP probability measures also improved their relationship with real crash outcomes.

Capitalising on these relationships, logistic regression techniques were able to successfully build accurate models of crashworthiness ratings and its components as a function of ANCAP measures, providing a direct functional relationship between the two programs as compatible and consistent measures of relative vehicle occupant protection.

Detailed analysis of injury data by body region broadly confirmed the results of the correlation analysis and was consistent with results of logistic regression modelling estimated using a more detailed and specific method of analysis. The relationships found, however, were not as strong as in the original study of Newstead and Cameron (1997). A strong statistically significant association was found between full frontal ANCAP femur loading readings and average maximum AIS to the leg region in real crashes along with a strong statistically significant association between the offset ANCAP chest loading and average maximum AIS to the chest in real crashes.

Sponsoring Organisation: NRMA Ltd, New South Wales RTA, VicRoads, Royal Automobile Club of Victoria Ltd. and Federal Office of Road Safety