An analysis of drug recognition expert evaluations and comparisons with police issued citations in Maryland, 2017-2021.

Abstract

Objective: Drug Recognition Expert (DRE) officers utilize standardized evaluations to assess physiological and behavioral indicators of drug impairment. This study analyzed data from Maryland DRE officers (2017-2021), comparing their drug category/ies assessments with blood tests results. DRE evaluation records were linked to citations issued for alcohol/drug-impaired driving, to examine the agreement between charges, DRE evaluation, arrest outcomes, and repeat offenses.

Methods: Data from 4,931 DRE evaluations were analyzed, involving 4,727 drivers linked to citation records for alcohol/drug-impaired driving offenses. Agreement between DRE opinions and blood test results was quantified by estimating binomial success probabilities with 95% confidence intervals. Citation outcomes and repeat offense rates for DRE and non-DRE cases were also presented.

Results: Of 4,931 unique evaluations, blood specimens were collected in 2,118 (42.9%), yielding 1,599 positive drug test results (75.5%). Most evaluated drivers were white (67.6%), male (73.8%), and aged 21-34 years (43.2%). Comparison of DRE opinion with blood test results revealed an overall success probability of 84.2 ± 0.65%. DRE accuracy improved to 91.8 ± 0.85% when none or one drug was detected and decreased to 80.5 ± 0.87% when two or more drugs were involved. When linked to citation data, 3,237 drivers (68.5%) received 36,878 citations, with 88.1% having two or more drug-related offenses and 72.5% having at least one negligent driving offense. Matched DRE drivers were involved in 9,105 traffic stops, with approximately 48.4% receiving over five citations during their first stop. 97.3% were cited for drug impairment, with only 87 drivers avoiding such citations.

Conclusions: This study highlights the effectiveness of the DRE program in identifying impaired drivers, providing insights into driver demographics and impairment patterns, while emphasizing need for improved polysubstance impairment data collection. A high degree of agreement between DRE opinions and blood test results for all tested drug categories were statistically established. Despite the program's success, significant gaps remain in testing methods and integrating alcohol and drug evaluations. Future research should enhance testing protocols, expanding data collection, and examining the link between substance use disorders and impaired driving to strengthen prevention, enforcement, and intervention efforts.