The Contribution of Beer Consumption to Drink Driving

Federal Office of Road Safety - Contract Report 152

Authors: K. Diamantopoulou, M. Cameron & N. Mullan

Abstract:

The main objective of this project was to estimate the proportion of drink-drivers on the road in Victoria who had consumed beer recently. In addition, the data collected was analysed in a way that allowed the role of beer to be estimated for crash-involved drink-drivers. Data was obtained from reports completed by Breathalyzer operators from drink-drivers apprehended at random breath test stations or through random routine Police cheeks. It was estimated that, during 1993/94, 64% of drink-drivers on the road had consumed beer-only prior to Police apprehension in Melbourne. Results for the rest of Victoria showed 78% of drivers had consumed beer only. Estimates obtained for crash-involved drink-drivers were similar to the on-road results, with 65% and 74% of drink-drivers consuming beer only prior to a crash in Melbourne and the rest of Victoria, respectively. Victorian alcohol sales patterns were compared to other Australian States and Territories and it was concluded that Victoria beer sales patterns were representative of the other jurisdictions.

Executive Summary

There is national interest in the proportion of drink-drivers who have consumed beer, for both drivers on the road generally and for those involved in crashes. This is because the National Road Safety Action Plan Implementation Taskforce has recommended that consideration be given to "increased differential excises and licence fees on alcohol products according to alcohol content to encourage the consumption of light alcohol products by drivers". The current focus is on encouraging a shift in consumption from full strength to low alcohol beer.

The main objective of this project was to estimate the proportion of drink-drivers on the road in Victoria who had consumed beer recently. The data was collected and analysed in a way which also allowed the role of beer to be estimated for crash involved drink-drivers. In addition, Victorian alcohol sales patterns, by type of beverage, were compared with those in other Australian States to assess the representativeness of Victorian alcohol consumption.

Two sources of data were used to obtain information on prior alcohol consumption of drink-drivers on the road. These were drink-drivers apprehended at random breath test stations and drink-drivers apprehended through random routine Police checks. In both cases, the ultimate source was a report completed by the Breathalyzer operator.

It was estimated that, during 1993/94, 64% of drink-drivers on the road had consumed beer only prior to Police apprehension in Melbourne, with 95% confidence limits on this estimate ranging from 61% to 67%. Amongst drink-driver apprehensions in the rest of Victoria, an estimated 78% of drivers had consumed beer only, with a confidence interval from 74% to 82%. An additional 13% of drink-drivers on the road in Melbourne and 11% in the rest of Victoria had consumed beer in combination with other alcoholic beverages.

Information on the relative risks of crash involvement of drink-drivers at specific blood alcohol levels, and in particular age groups, was used to weight the data obtained from drink-drivers on the road so that it provided estimates of the prior alcohol consumption of drink-drivers involved in crashes.

An estimated 65% of drivers involved in crashes had consumed beer only prior to drink-driving in Melbourne. In the rest of Victoria, the estimated proportion of crash involved drink-drivers who had consumed beer only was 74%. Additionally, an estimated 13% of crash-involved drink-drivers in Melbourne and 11% in the rest of Victoria had consumed beer in combination with other alcohol.

Victorian beer sales patterns (and alcohol sales in general) were representative of other Australian States for the 1992/1993 financial year. Hence the estimates of the proportion of drink-drivers who consumed beer in Victoria were considered to reflect the drink-driving patterns of the rest of Australia.