Effectiveness of ADR 69: A case-control study of crashed vehicles equipped with airbags

Authors: Morris, A., Barnes, J., Fildes, B., Bentivegna, F. & Seyer, K

Australian Transport Safety Bureau - Contract Report No. 199

Full report in .pdf format [908KB]

Abstract

Australian Design Rule (ADR) 69 called for all new passenger cars to comply with a dynamic full frontal barrier crash test requirement, similar to US safety standard FMVSS 208 but with restrained test dummies. This study set out to evaluate how effective ADR 69 has been at preventing injuries and Harm to passenger car occupants in Australia since its introduction.

A case-control study of real-world crashed vehicles equipped with and without Supplementary Restraint Systems was conducted. Data included 253 drivers in airbag-equipped vehicles and 130 drivers in non-airbag vehicles, involved in a frontal collision. The analysis revealed reductions in the numbers of injuries to the head, face, chest and neck in the airbag-equipped vehicles although the numbers of upper extremity injuries increased. At higher injury severities (AIS2+) reductions were also observed in injuries to the head, face, neck and chest. Further analysis using Harm as an outcome measure found that the mean Harm per driver (in terms of $AUD) was 60% greater in the non-airbag vehicles compared with the airbag-equipped vehicles. The main conclusion from the study was that the results offer a strong indication that the Australian Design Rule (ADR) 69 requirement has been successful in addressing some of the outstanding issues that remain for injury prevention for drivers involved in frontal impacts.

Executive Summary

In 1989, the Australian Federal Office of Road Safety (FORS) embarked upon a comprehensive 3-year crash investigation, testing and standards development programme. The aim of this programme was to examine passenger car occupant injuries in frontal crashes and to develop appropriate countermeasures to minimise the level and type of injuries occurring.

The end result of the programme was the introduction of a dynamic full frontal crash protection requirement on passenger cars sold in Australia: Australian Design Rule (ADR) 69. This performance-based standard requires vehicle manufacturers to design their Australian passenger models to meet specific injury level criteria for a particular crash configuration. The type of vehicle design changes incorporated to meet the new ADR requirements were left to individual manufacturers.

The regulation was based on the US Federal Motor Vehicle Safety Standard FMVSS208 but importantly specified that the Hybrid III test dummies be restrained with a seat belt. This led to the adoption of Supplementary Restraint Systems in Australian vehicles, which are less aggressive and fire at higher thresholds than their American counterparts.

The ADR 69 took effect on 1 July 1995 with design changes in response to the ADR being quickly implemented in the Australian market place. This was clearly demonstrated by the increased availability of airbags across new model ranges. Although airbags were not the only option open to vehicle manufacturers to meet ADR 69 requirements, the majority of vehicle manufacturers demonstrated a strong preference for them.

In order to evaluate the impact of ADR 69 on passenger car occupant injuries, the Federal Office of Road Safety commissioned the Monash University Accident Research Centre to undertake an analysis of real-world crashes to evaluate its effectiveness. A programme was subsequently developed that allowed occupant injuries to be compared in a representative sample of pre- and post-ADR 69 passenger vehicles.

Study Objectives

The objectives of the study were:

  • to assess the effectiveness of new occupant protection measures, particularly the airbag, in reducing trauma on the road;
  • to identify any problems associated with new occupant protection measures (e.g. failure of airbag to deploy, injuries caused by the new safety devices);
  • to ensure that information about the impact of ADR 69 and airbags is available for public policy purposes; and
  • to highlight areas where further improvement in occupant protection systems are still required.

The methodology adopted for the study involved a case-control analysis of crashed vehicles equipped with and without SRS airbag technology. Vehicles were inspected and occupants interviewed according to the National Accident Sampling System (NASS). Overall data were available for 476 individual vehicles involved in frontal impacts. This sample was further refined so that comparative groups could be defined particularly in terms of crash severity.

Study Results

There was a total of 383 belted drivers involved in frontal crashes in the comparative sample groups, including 253 drivers in airbag-equipped vehicles and 130 drivers in non-airbag vehicles. The analysis revealed statistically significant reductions in the numbers of injuries (at all levels) to the neck (p<0.007) in the airbag-equipped vehicles although the numbers of upper extremity injuries increased significantly (p<0.001).

Other reductions in injury frequency were observed which were non-significant. At higher injury severities (AIS2+), significant reductions were observed in injuries to the head (p<0.02), neck (p<0.05) and chest (p<0.01).

Further analysis found that the average societal Harm per driver (in $AUD) was 60% greater in the non-airbag vehicles compared with the airbag-equipped vehicles. Thus airbags in Australia offer a significant saving in terms of costs to society when used in conjunction with the seat belt.

Conclusions

This study is the most comprehensive study of the ADR 69 requirement that has been performed to date in Australia. The results offer a strong indication that it has been successful at addressing injuries sustained by front seat occupants in frontal crashes. These benefits accrue from an improved occupant protection system including a driver’s side airbag and an improved seat belt system.

Manufacturers are now in the process of developing second generation airbags and it is important that evaluations of these systems are also undertaken through real-world studies such as this. This is particularly as laboratory crash tests of improved vehicle technology and enhanced legislation can never provide a thorough analysis of the effectiveness of such advancements.