The criminalization of impaired driving in Canada: assessing the deterrent impact of Canada's first per se law.
OBJECTIVE
The goal of this article is to assess the effectiveness of Canada's first per se law criminalizing driving with a blood alcohol concentration of over 0.08%, the Breathalyser Law introduced in 1969, in reducing drinking-driver-related fatalities. We also examine the long-term deterrent effect of this law on driver fatality rates. In the analyses we include such potentially confounding influences on drinking-driver fatality rates as the founding of Mothers Against Drunk Driving (MADD), Canada; the introduction of Ontario's mandatory seatbelt law; per capita alcohol consumption; the unemployment rate; vehicles registered per capita; and precipitation rates.


METHODS
Interrupted time series analysis with auto-regressive integrated moving average modeling was applied to the annual number of motor vehicle driver fatalities in Ontario for the period 1962-1996 to examine drinking- and nondrinking-driver fatalities.


RESULTS
A significant intervention effect was found for the Breathalyser Law in Ontario, which was associated with an estimated reduction of 18% in the number of fatally injured drinking drivers. No corresponding effect was observed for nondrinking-driver fatalities. Per capita alcohol consumption was positively associated with drinking-driver fatalities; Ontario's mandatory seatbelt law was linked to nondrinking-driver fatalities; and the formation of MADD, Canada, was strongly associated with drinking- and nondrinking-driver fatalities.


CONCLUSIONS
These data provide evidence that Canada's per se law had a specific deterrent effect that resulted in a reduction in drinking-driver fatalities. A long-term deterrent effect was also observed, which is in contrast to the early policy literature on impaired driving.
Asbridge
Mark
M
Department of Community Health and Epidemiology, Dalhousie University, 5790 University Avenue, Halifax, Nova Scotia B3H 1V7, Canada. Mark.Asbridge@dal.ca
Mann
Robert E
RE
Flam-Zalcman
Rosely
R
Stoduto
Gina
G
D000428:Alcohol Drinking / Q000453:epidemiology* / Q000331:legislation & jurisprudence*; D001334:Automobile Driving / Q000706:statistics & numerical data*; D001944:Breath Tests / Q000379:methods; D002170:Canada / Q000453:epidemiology; D003416:Criminal Law / Q000331:legislation & jurisprudence* / Q000706:statistics & numerical data*; D006801:Humans