DRE’s are often called in to perform a 12-step evaluation on a driver suspected of being under the influence of a drug after the driver has been involved in a motor vehicle crash. Since the DRE spends time clearing the driver of possible medical and/or physical impairment during step 3 of the evaluation, the DRE feels administering an evaluation on a driver involved in a crash is acceptable. But is it acceptable?
There are 2 NHTSA studies that validated the DRE program, the 1984 Johns Hopkins Laboratory Validation Study (DOT HS 806 753) and the 1985 LAPD Field Validation Study (DOT HS 807 012). Both studies are available in our members only virtual library.
The 1985 field validation study was based on 173 people arrested on suspicion of driving under the influence of drugs. Twenty‐eight DREs from LAPD and the Los Angeles area participated in the study.
The key finding of this study was for more than nine out of ten of the subjects (92.5%), the blood test confirmed the presence of at least one drug category opined by the DREs. But there is a rarely taught and often forgotten take-away from this study: None of the 173 subjects were involved a crash.
According to the NHTSA DRE student manual, “[Researchers] excluded all cases that involved crashes since the subjects’ injuries could have confounded the drug examination.” (2018 revision, session 3, page 14). So even during the initial validation of the DRE program, researchers realized DRE’s could confuse injuries for drug impairment.
Bottom line: DRE evaluation + motor vehicle crash = invalid and unreliable opinion.