Pilot test of selected driving while intoxicated detection procedures for use at sobriety checkpoints

NHTSA - Behavioral Safety Researchhttps://doi.org/10.21949/15252001985PDFTech ReportCompton, Richard P.United States. National Highway Traffic Safety Administration. Office of Driver and Pedestrian ResearchUnited States. National Highway Traffic Safety AdministrationUnited StatesAlcohol testsDrunk drivingSobriety checkpointsTraffic law enforcementPilot studiesDOT-HS-806-724NTIS-PB86170958This report presents the results of a study designed to evaluate a variety of potential screening procedures police officers could use at the brief initial stop at a sobriety checkpoint to discriminate between impaired and sober drivers. The potential checkpoint screening procedures examined in the study included the horizontal gaze nystagmus test, observations of driving and stopping behavior, the driver's personal appearance, a divided attention task and a passive alcohol sensor. In the study, dosed and sober drivers drove their own cars down a closed street and were stopped by police officers at a sobriety checkpoint. The setting of the experiment and the procedures used were designed to closely simulate the conditions found at real checkpoints. The results indicated that the officers using a test screening procedure were able to accurately discriminate between impaired drivers (those with a breath alcohol level of 0.10% or higher) and sober drivers. The officers correctly identified 95% of the impaired drivers while misidentifying few of the sober drivers. The accurate performance of these officers appeared to be primarily due to the use of the gaze nystagmus test. Also, the passive alcohol sensor was accurate in detecting whether the driver had been drinking. The sensor correctly identified 94% of the impaired drivers (who had BACs of 0.10% or higher) as having been drinking, while misidentifying 10% of the sober drivers. These screening procedures produced a more accurate discrimination between impaired and sober drivers than did police officers using a common technique of stopping a vehicle, speaking briefly with driver and then making a subjective judgment. These results suggest that the typical checkpoint screening procedure (where the officers simply observe the driver and form a subjective opinion) can be improved by the use of techniques like the nystagmus test or a properly designed and used passive sensor. /Abstract from report summary page/129