October 31, 2011

Fewer Canadian drivers alcohol-impaired in U.S. fatal car crashes

A new study by researchers at the Johns Hopkins Center for Injury Research and Policy and at Columbia University finds that the rate of alcohol involvement in fatal motor vehicle crashes in the United States is much lower among drivers with Canadian licenses than among drivers with U.S. or Mexican licenses.

The prevalence of alcohol involvement in fatal crashes was 27 percent for both U.S. and Mexican drivers, and 11 percent for Canadian drivers. Similarly, alcohol impairment was found in 23 percent of U.S. and Mexican drivers and 8 percent of Canadian drivers involved in a fatal crash. Research from other countries finds that foreign drivers are at greater risk of crashes than native drivers. In contrast, this study shows that drivers licensed in Mexico and Canada who were involved in fatal crashes in the United States had the same or less alcohol impairment than U.S.-licensed drivers. The report is published in the October issue of Injury Prevention and is available on the journal’s website.

“Our findings were unexpected, partly because the substantial cultural differences between the U.S. and Mexico led us to anticipate differences in alcohol-related crashes,” said lead study author Susan P. Baker, a professor with the Johns Hopkins Center for Injury Research and Policy, part of the Johns Hopkins Bloomberg School of Public Health. “We also anticipated that Canadian drivers in U.S. crashes would be similar to U.S. drivers because the rate of alcohol-related fatal crashes is similar within the two countries.” Together, Mexican and Canadian drivers comprise more than 70 percent of all foreign-licensed drivers involved in fatal crashes in the United States.

As a possible explanation, the researchers speculate that the less prominent role of alcohol in fatal crashes of Canadian-licensed drivers in the United States may suggest that a larger proportion of Canadians were traveling on family vacation or business, situations that may be less likely to involve alcohol. Crashes at night, when alcohol is more likely to be involved, were also least common among Canadian-licensed drivers. And finally, it is also possible that Canadians are less likely to drive after drinking.

Data for this study came from the Fatality Analysis Reporting System, a National Highway Traffic Safety Administration database of fatal traffic crashes. Study subjects were drivers age 16 years or older who were licensed in the United States, Mexico or Canada and involved in a U.S. crash from 1998 to 2008 that resulted in at least one death. Alcohol involvement was defined as having a blood alcohol content of 0.01 g/dl or greater, and alcohol impairment was defined as having a blood alcohol content of 0.08 g/dl or higher.

Additional authors of the study are Joanne E. Brady and Guohua Li, both of Columbia University; and George W. Rebok, of Johns Hopkins.

The research was supported in part by the National Institutes of Health and the National Center for Injury Prevention and Control, part of the Centers for Disease Control and Prevention.