Australian design rule (ADR) 22a requires head restraints to be fitted to driver and front left seats of all new cars in australia from 1975 models onwards. This study was based on 1977-78 claims to a "no-fault" injury compensation scheme operated by the motor accidents board (MAB) in victoria. Potential benefit groups (front outboard seat occupants in rear end impacts) and disbenefit groups (front and rear seat occupants in front end impacts) were considered. The study concluded that ADR 22a head restraints are effective in reducing whiplash injuries to female front occupants aged 17-49 involved in rear end impacts. The analysis was inconclusive regarding the benefits to male front occupants in these impacts due to the possibility that their benefit (if any) from ADR 22a may be offset or eroded by an increase in whiplash injuries due to increased seat belt wearing in the front seats of ADR 22a cars, resulting in little or no apparent benefit. The absence of information on crash severity and seat belt wearing from the analysed data limited the conclusions to being suggestive, not definitive. However, there appears to be a case for upgrading ADR 22a to increase the minimum height of head restraints, so that male front seat occupants are more frequently protected. Installation of head restraints in rear seats does not appear to be justified by the number of whiplash injuries occurring.
Samenvatting