Fatal crash data. Data from 1982 to date from the seven provinces for which these data are available (Alberta, British Columbia, Manitoba, New Brunswick, Ontario, Prince Edward Island, and Saskatchewan) were provided by the Transport Injury Research Foundation (TIRF). The data differ slightly from the United States FARS data in three ways. First, they record driver fatalities rather than driver involvements in fatal crashes. Second, they aggregate drivers age 16-19 rather than drivers under 21 as has been used for the United States. Finally, the TIRF file does not estimate alcohol presence for a driver without a BAC test. The proportion of fatally injured drivers with a positive BAC is calculated only for the drivers with a BAC test. Most drivers are tested: 76 percent of the age 16-19 driver fatalities in 1982 and 93 percent in 1997.
These differences may affect comparisons between the Canadian and United States data somewhat. For example, if BAC tests are available less frequently for sober drivers than for drinking drivers, then the proportion of fatally-injured drivers with a positive BAC calculated only from the tested drivers may overstate the proportion for all fatally-injured drivers. But these differences should not affect the trends over time or trend comparisons between the two countries.
Figure 31 shows the trend in Canadian fatally-injured drinking drivers aged 16-19. It looks rather similar to the United States trend of Figure 1, with a rapid decrease through about 1993 and no substantial change since then. (The Canadian trend fluctuates more from year to year than the United States trend since the absolute number of Canadian traffic fatalities is much smaller.) Figure 32 shows how very similar the two trends are by plotting both using a base of 1982 = 100 percent.
Figure 31.
Canadian Driver Fatalities, Age 16-19, with Positive BAC
Figure 32.
US and Canadian Trends, Percentage Change from 1982
US: drivers under age 21 in fatal crashes with positive BAC (FARS)
Canada: driver fatalities age 16-19 with positive BAC (TIRF)
Figure 33 shows the trend in the proportion of fatally-injured Canadian drivers with a positive BAC. The trend is similar to the corresponding United States trend of Figure 3. The absolute percentages are higher in Canada: 67 percent in 1982 (compared to 43 percent in the United States) and 39 percent in 1997 (compared to 21 percent). Some of this difference may be a result of the different methods used to estimate alcohol involvement in the two data files. Some may in fact reflect higher drinking and driving rates in Canada. But the trends in the two countries again appear very similar. Figure 34 compares the trends directly.
Figure 33.
Percent of Canadian Driver Fatalities, Age 16-19, with Positive BAC
Figure 34.
US and Canadian Trends, Percentage Change from 1982
US: percentage of drivers under age 21 in fatal crashes with positive BAC (FARS)
Canada: percentage of driver fatalities age 16-19 with positive BAC (TIRF)
Figures 32 and 34 show the same thing:
as measured by fatal crash data, youth drinking and driving decreases in the United States and Canada from 1982 to 1997 were virtually identical. Other data strengthen this conclusion. In both countries, the number of young drinking drivers in fatal crashes decreased more rapidly than the number of older drinking drivers. A roadside survey in British Columbia produced results similar to Roeper and Voas (1999): a much smaller proportion of drivers age 16-19 than older drivers had a positive BAC, or a BAC exceeding the legal limit of 0.08 (Mayhew and Simpson, 1999).
Survey data. Smart, Adlaf, and Walsh (1994) report on biennial surveys of about 4,000 Ontario high school students similar to the Monitoring the Future surveys in the United States. Table 17 summarizes self-reported drinking changes from 1979 to 1991 from the two surveys.
Since the Ontario data come from a sample of students in grades 7-13, while the United States data come from high school seniors, it's no surprise that overall self-reported drinking levels are lower in Ontario. The reductions, though, are generally similar: a modest reduction in annual drinking, substantial reductions in binge drinking, and reductions close to 50 percent in both daily drinking (at low levels in both countries) and driving after drinking.