Research Papers

Abstract

In the spring of 2010, the Government of British Columbia announced new measures to deal with drinking drivers that would be implemented in the fall. As part of an evaluation of the impact of these new measures on the drinking-driving behaviour of drivers, a random survey of nighttime drivers was conducted to gather information on the prevalence of alcohol and drug use. In addition, the survey extended the findings from a previous Roadside Survey to include a community in Northern British Columbia as well as a community from the interior. Drivers were randomly selected from the traffic stream between the hours of 9 PM and 3 AM on Wednesday to Saturday nights and asked to provide a voluntary breath sample to measure their alcohol use and an oral fluid sample to be tested subsequently for the presence of drugs. Unique to this study was the quantification of cannabis in oral fluid samples. Of the 2,840 vehicles selected, 86% of drivers provided a breath sample and 71% provided a sample of oral fluid. It was found that 9.9% of drivers had been drinking. More importantly, 1.4% of drivers had a BAC between 50 and 80 mg% and 2.2% had a BAC in excess of 80 mg%, including several drivers with BACs over 160mg%. It was found that 7.2% of drivers tested positive for drug use. Cannabis and cocaine were the drugs most frequently detected in drivers. The quantification of the positive cannabis samples indicates that drivers are using a significant amount of the drug prior to driving with the majority of samples being over 40 ng/ml. Similar to the 2008 study, alcohol use among drivers was most common on weekends and during late-night hours; drug use was more evenly distributed across all survey nights and times. Community differences were also observed. Alcohol and drug use among drivers remains a common behaviour on British Columbia roadways.

Erin Beasley and Douglas J, Beirness