HOW DRUNK ARE U.S. DRIVERS? MEASURING THE EXTENT, RISKS AND COSTS OF DRUNK DRIVING

This study develops and applies an algorithm with broad applicability for estimating vehicle miles traveled by Blood Alcohol Level (BAL) from police accident report data. In the United States, an estimated one in 120 miles was driven drunk in 1992–1993. For 1 in 7 miles driven after 1 AM on weekend evenings, a drunk sat behind the wheel. The estimated cost per DWI vehicle mile was $5.80 compared to $0.11 per sober mile. Males, those age 21 to 29, and those driving between 10 PM and 4 AM had the greatest percentage of alcohol-impaired driving. These estimates are computed, in part, from early-1960s data on crash odds by driver BAL and assume crash odds by BAL relative to sober do not vary with driver age and sex. The method reproduces alcohol-positive miles from roadside surveys at night well, but seems to over-estimate high-BAL miles. Direct field validation is highly desirable.