Citation

Johnson M. Transp. Res. Circular 2009; (E-C132): 224-234.

Copyright

(Copyright © 2009, U.S. National Academy of Sciences Transportation Research Board)

DOI

unavailable

PMID

unavailable

Abstract

Ever since illegal impaired driving could be defined in terms of a specific blood alcohol concentration (BAC), safety specialists have expressed concern about the absence of a method for a driver to measure his or her own BAC. Those who oppose lower BAC limits argue that it is practically impossible for a drinker to determine his or her status with respect to the law. When both the driver?s BAC and the legal driving limit are known, however, drivers presumably will make more rational choices when weighing the risks associated with driving after drinking. Several studies have been conducted of drinkers? ability to estimate their own BACs. These studies suggest that individuals rely on internal sensations or on counting drinks to make their estimates, which often are different from their actual BAC levels. There is a reasonable argument that the drinking public could make more rational decisions about driving after drinking if they could accurately measure their BACs. Nevertheless, few studies have examined the effect of BAC estimation tools on impaired driving, and to the author's knowledge, no research has investigated how BAC feedback affects drinkers? perceptions of their impairment and their risk of driving under the influence (DUI) arrest. This paper briefly discusses the tools for estimating BACs and the risks of providing BAC estimates in real-world settings. It then reports the results of two studies. The first study interpreted the magnitude of the correlation between BAC and subjective impairment ratings as an indicator of sensitivity to driving impairment. The second study took place in a real world drinking environment and examined whether providing BAC estimation tools would have any effect on alcohol consumption of drivers and passengers.