Data from police random breath testing (RBT) and alcohol tests of crash-involved drivers were used to assess the effects of a reduction in the maximum permitted blood alcohol concentration (BAC) for driving. Most debate on selection of legal drink-driving limits has focused on the assessment of driving impairment and crash risks at BACs below the current legal limit in the relevant jurisdiction. However, some previous research has indicated that one of the major benefits of a lower BAC limit may be a reduction in drink driving at very high BAC levels, well above the original limit. Results from this study support that hypothesis. The maximum legal BAC for driving in the Australian Capital Territory (ACT) was changed from .08 to .05 on 1 January 1991. RBT results for 1991 showed a reduction of 41 per cent in the incidence of drink driving at BACs above .15, compared to 1990, as well as a reduction of about 90 per cent in drink-driving at BAC levels between .05 and .08.
Type: Research and Analysis Report
Sub Type: Minor Report
Author(s): Chris Brooks & Dominic Zaal
Publication Date: 01/09/92