The accuracy of estimating the sobriety of drinking drivers

Abstract

The mere act of driving with a blood alcohol level (BAL) of 10% + is punishable in many states. In addition, under the so-called dram shop law the proprietor of an establishment or a host at a private party at which liquor is served to a person who subsequently commits an alcohol-related offense may be prosecuted and held liable for damages incurred by that individual. It is apparent that an increasingly larger number of law enforcement personnel and private citizens will be required to Judge the sobriety of others. The purpose of this paper is to evaluate the accuracy of such estimates. BAL data were obtained from 1,115 drivers at a roadside survey during which each interviewer was required to estimate the sobriety of the driver. At highway patrol sobriety checkpoints the number of drivers arrested was compared with the number of drivers in the sample estimated to possess BALs of .10% or higher. Both sources correctly identified approximately 21% of those drivers with BALs of .10% or higher.