; and Voas, R.B.
In Proceedings of the 16th International Conference on Alcohol, Drugs and Traffic Safety
pgs. 67-71 , Montreal, Canada: Société de l'assurance automobile du Québec (2002)
Editor(s): Mahew, D.R.; and Dussault, C.The evaluation of the effectiveness of new alcohol safety laws and programs is critical to the development of a successful national system for reducing alcohol-related crashes. Although evaluations of U.S. laws, such as those reducing the legal blood alcohol concentration (BAC) limit to .08 or establishing zero tolerance laws for youth 21 years old and younger, have been conducted, it often has been difficult to compare the results because of the differing outcome measures used. The measures reported include all crashes, single-vehicle crashes, nighttime crashes, "had-been-drinking" crashes, and crashes involving drivers with positive or high BACs. All of these measures fail to include a term reflecting the underlying rate of non-alcohol-related crashes, which can be influenced by the quality of vehicles, roadways, urbanization, and the economy, among other factors.
A standard method for reporting health statistics is to use population as the normalizing measure. However, since access to a vehicle varies by socioeconomic class and urban rural location, vehicle miles of driving (VMT) appears to be the method of choice for normalizing highway injuries. However, VMT is of limited value for normalizing alcohol-related injuries because the proportion of vehicle miles of travel that involve an impaired driver is more difficult to determine and not available in the state estimates derived from state gas taxes. Conversely, non-alcohol-related crashes occurring at the same times or locations or to the same groups of drivers can provide a more specific method of normalizing alcohol-related events by controlling more specifically for vehicle type, roadway conditions, or driver characteristics. Thus, for example, the frequency of alcohol-related crash involvements to non-alcohol-related crash involvements can be compared for specific at-risk groups such as African American males ages 21 to 35, a specific group for which vehicle miles of travel are not available. This paper illustrates the use of that type of normalization in comparison vehicle miles of travel in analyzing alcohol-related crash involvements by age and gender.