The objective of this study was to re-examine and refine estimates for alcohol-related relative risk of driver involvement in fatal crashes by age and gender as a function of blood alcohol concentration (BAC) using recent data. The method of study was logistic regression, which was used to estimate age/sex specific relative risk of fatal crash involvement as a function of the BAC of fatally injured and surviving drivers by combining crash data from the Fatality Analysis Reporting System with exposure data from the 1996 National Roadside Survey of Drivers. In general, the relative risk of involvement in a fatal passenger vehicle crash increased steadily with increasing driver BAC in every age/sex group among both fatally injured and surviving drivers. A .02 percentage point BAC increase among 16-20 year old male drivers was estimated to more than double the relative risk of fatal single vehicle crash injury. At the midpoint of the .08-.10 BAC range, the relative risk of a fatal single-vehicle crash injury varied between 11.4 (drivers 30 and older) and 51.9 (male drivers, 16-20). With few exceptions, older drivers had lower risk of being fatally injured in a single vehicle crash than younger drivers, and females were at lower risk than comparable males. This is the first study that systematically estimated relative risk for drinking drivers with BACs between .08% and .10% (these relative risk estimates apply to BAC range mid-points at .09%). The results clearly show that drivers at non-zero BACs somewhat below .10% pose substantially elevated risk both to themselves and to other road users. (A)
Abstract