The purpose of this scientific review is to provide a summary of the evidence regarding the benefits of reducing the illegal blood alcohol concentration (BAC) for driving and providing a case for enacting a .05 BAC Criminal Code limit in Canada. With regard to the effectiveness of .08 BAC laws, the research is consistent and persuasive that such laws are associated with reductions in alcohol-related crashes. Twelve independent studies have been conducted, covering 18 states that have enacted .08 BAC laws. On average, .08 BAC laws have resulted in 6-16 percent reductions in alcohol-related crashes, fatalities, or injuries. The U.S. has taken the lead in adopting lower BAC limits for underage youth. These “zero tolerance” laws for youth lowered the illegal BAC limits for that population and have proven to be effective in reducing underage drinking driver fatal crashes. A systematic review of zero tolerance laws and their effect on alcohol-related injuries and fatalities showed reductions associated with the implementation of these laws. The international trend continues to be to reduce illegal criminal per se limits to .05 BAC or lower. The illegal limit is .05 BAC in numerous countries including: Australia, Austria, Belgium, Bulgaria, Croatia, Denmark, Finland, France, Germany, Greece, Israel, Italy, the Netherlands, Portugal, South Africa, Spain and Turkey. Russia, Sweden and Norway have a limit of .02 BAC and Poland recently went to .03 BAC. Several countries have reported studies indicating that lowering the illegal per se limit from .08 BAC to .05 BAC reduces alcohol-related fatalities. Laboratory studies indicate that impairment in critical driving functions begins at low BACs and that most subjects are significantly impaired at .05 BAC with regard to visual acuity, vigilance, drowsiness, psychomotor skills, and information processing compared to their performance at .00 BAC. The relative risk of being involved in a fatal crash as a driver is 4 to 10 times greater for drivers with BACs between .05 and .07 compared to drivers with .00 BACs. Leading medical, crash prevention, public health and traffic safety organizations in the world support BAC limits at .05 or lower. A report issued by the Traffic Injury Research Foundation (TIRF) in May 2002, entitled “The Safety Impact of Lowering the BAC Limit for Drivers in Canada,” concluded that “the evaluation literature failed to provide strong, consistent and unqualified support for lowering BAC limits. At best, the results are mixed and the methodological weaknesses in the studies question the robustness and veracity of the evidence” (Beirness & Simpson, 2002). We have conducted a critical review of the Beirness & Simpson report (also referred to as the TIRF report) and find ourselves in disagreement with the TIRF conclusion for several reasons: 1. The methodological limitations cited by Beirness and Simpson in studies of the effects of lower BAC limits are present in most field studies, including those of the effects of administrative license revocation (ALR), graduated driver licensing (GDL) laws, and measures to reduce “hard core” drinking drivers, which TIRF prominently endorses. Even considering these limitations, the scientific community in general has concluded that lower BAC limits are effective, contrary to the TIRF conclusion. 2. The TIRF report fails to note that the U.S. Centers for Disease Control (CDC) reviewed the existing studies on the lowering of the BAC limit from .10 to .08 and came to the conclusion that such laws reduce alcohol-related fatalities by 7%. 3. The interpretations of the results of many of the studies reviewed by TIRF are one-sided and not representative of the body of scientific opinion. If the same interpretations were held for studies of GDL laws, for example, TIRF would have to withdraw their support for such laws. 4. There are other good reasons and other evidence for lowering the BAC limit to .05 in Canada that were not discussed by TIRF in their report (e.g., impairment and crash risk at .05 BAC). 5. Several studies which showed positive findings on the lowering of BAC limits were available to TIRF when they conducted their review but were not mentioned in their report. In conclusion, even considering certain methodological limitations in the studies, there is strong and consistent evidence in the literature that lowering the blood alcohol concentration (BAC) limit from .10 to .08 is effective, that lowering the BAC limit from .08 to .05 is effective, and that lowering the BAC limit for youth to .02 or lower is effective. All of these measures serve as a general deterrent to drinking and driving and ultimately save lives. It is recommended that Canada strongly consider lowering their illegal BAC limit to .05. (Author/publisher)
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