Using a passive alcohol sensor to detect legally intoxicated drivers

Objectives. We examined whether a passive alcohol sensor could be used for mass screening of motorists to accurately and quickly detect drivers whose blood alcohol concentration exceeded a variety of levels often established as per se evidence of legal intoxication. Methods. In a voluntary roadside survey, 1181 late-night drivers in Minnesota were interviewed. Breath measurements were taken with both a passive alcohol sensor and an evidentiary quality portable breath-test device. Results. Measurements could be taken much more easily and quickly with the passive sensor, whose readings correlated very strongly (r = .87) with the evidentiary device. Moreover, for criterion blood alcohol concentration levels ranging from 100 mg/dL to 20 mg/dL, a large proportion of motorists could be accurately identified as being above or below the criterion, with relatively few false-negative or false-positive identifications. Conclusions. The use of passive alcohol sensors at sobriety checkpoints should allow motorists to be processed very quickly with minimal inconvenience. At the same time, detection of legally intoxicated motorists will probably be substantially increased and the general deterrent value of per se alcohol-impaired driving laws enhanced.