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Field Evaluation of the Los Angeles Police Department Drug Detection Program

NCJ Number
Date Published
51 pages
A 3-month field study was conducted in 1985 to evaluate the ability of trained Los Angeles Police Department drug recognition experts (DRE's) to identify drug-impaired drivers and the class of drug involved (e.g., stimulants, depressants, marijuana).
A total of 219 suspects were evaluated by 25 DRE's using a combined interview, physiological symptom, and behavioral testing procedure. Suspects' blood samples were analyzed for eight substances, including alcohol. When DRE's judged drugs other than alcohol to be present, they were detected 94 percent of the time in the blood samples. DRE's were able to correctly identify at least one drug other than alcohol in 87 percent of the suspects. When DRE's identified a suspect as impaired by a specific drug, that drug was detected in the blood sample 79 percent of the time. The accuracy of drug identification varied among drugs, with accuracy being greatest for phenycyclidine and least for cocaine. Supplemental research information is appended. 9 tables and 3 references. (Author abstract modified)