Skip to main content
You can also sort pages by filters.
Table of Contents
Download the Full Book

Effectiveness: 3 Star Cost: $$
Use: Unknown
Time: Short

Enforcement of drug-impaired-driving laws can be difficult. Investigations often follow from an officer’s suspicion of a driver’s impairment, but when their BAC is not consistent with impairment. If drivers have BACs over the legal limit, many agencies do not allow for additional testing. This additional testing can be costly and in many States poly substance use does not carry additional penalties.

Several devices are available that allow officers to screen suspects for the presence of drug categories at point-of-contact, with varying degrees of sensitivity, specificity, and accuracy, although their efficacy is improving (Buzby et al., 2019; Compton et al., 2009; Dobri et al., 2019; Peaire et al., 2018). For a more in-depth discussion of roadside testing, see Drug-Impaired Driving – Emerging Issues.

NHTSA has developed several courses in collaboration with the International Association of Chiefs of Police (IACP) to assist law enforcement officers with the investigation of suspected drug-impaired driving cases. Law enforcement officers who have completed training in DWI detection and SFST can participate in the Advanced Roadside Impaired Driving Enforcement (ARIDE) program. This is a 16-hour course designed to enhance officers’ knowledge of the impairing effects of alcohol, other drugs, and polydrug use including alcohol. To achieve this, ARIDE trains officers to properly administer SFSTs, and to “observe, identify, and articulate observable signs of drug impairment” (NHTSA, 2018, p. 9) with the seven drug categories[1] established by the Drug Evaluation and Classification (DEC) program. ARIDE serves as a bridge between the SFST and the more advanced DEC program, also known as the drug recognition program (NHTSA, 2018). The DEC program trains law enforcement officers through a three-phase training process: DRE pre-school (16 hours), DRE school (56 hours), and DRE field certification (~40 to 60 hours). Upon completion DREs are certified to conduct a 12-step protocol to determine three things: (1) whether the person is impaired, (2) whether this impairment is related to drug impairment or a possible medical condition, and (3) if drug impaired, the category or categories of drugs likely causing the impairment. In most instances the evaluation takes approximately 1 hour to complete. If drug intoxication is suspected, a blood, oral fluid, or urine sample is collected and submitted to a forensic laboratory for screening and confirmation testing (DEC Program Technical Advisory Panel, 2020; NHTSA, 2018b; NHTSA, 2018c).


As of 2022 there were 8,350 active DREs, of whom 1,605 are also instructors, representing all 50 States and the District of Columbia. In addition, from 2009 to 2022 some 155,875 officers and public safety officials received ARIDE training. Also, in 2022 there were 23,278 drug enforcement evaluations conducted by DREs (IACP, 2023). However, it should be noted that the number of drug-impaired driving arrests cannot be known as many States only record “impaired driving” arrests, and do not separate alcohol from drug arrests. It is suspected that many arrests are a combination of drugs and alcohol. Among the drug recognition evaluation opinions voluntarily reported to the NHTSA DRE Database (ICAP, 2023), CNS stimulants was the most frequently identified drug category, followed by cannabis, narcotic analgesics (opioids), and CNS depressants.


Overall, the evidence supporting the ability of DREs to accurately classify the drug responsible is mixed. While several studies have found above 85% agreement between the DRE and the toxicological test results (NHTSA, 1996), other studies have found lower percentage agreement (Shinar et al., 2000). The accuracy of the evaluation is likely highly dependent on the level of experience of the DRE, the category of drug involved, and the numbers of drugs involved (the consumption of several drugs can hide some signs and symptoms and enhance others).

To date, research has not directly identified strategies to reduce drug-impaired driving over and above those used for alcohol use and driving due to the considerable complexities involved with performing such research. However, there has been considerable work done examining the impacts of decriminalization and legalization of cannabis on several aspects of the DWI system, including prevalence and enforcement. See the joint report by NHTSA, GHSA, and the Volpe National Transportation Systems Center (2017) and Otto et al. (2016) for comparative discussions across States.


As with other enforcement strategies, the primary costs are for law enforcement time and training. The time to conduct a DRE evaluation is approximately 1 hour. Training includes 72 hours of classroom instruction and approximately 50 hours of field work (NHTSA, 2018c). In addition, DREs must be recertified every 2 years. At a minimum this involves four acceptable evaluations since the date of last certification, 8 hours of recertification training, and submission of an updated Curriculum Vitae and rolling log to the appropriate coordinator for review (ICAP, n.d.). The time required for ARIDE training is considerably less, involving 16 hours of classroom instruction (NHTSA, 2018).

Time to Implement:

Drug-impaired driving enforcement can be integrated into other enforcement activities within 3 months; however, time will be needed to train DREs in detecting drug impairment. DRE training consists of 72 hours of classroom instruction, and DRE candidates are also required to perform several supervised field evaluations to become certified (Compton et al., 2009). Providing ARIDE training takes less time to deliver (16 classroom hours), but principal instructors must have suitable qualifications, including current certification as a DRE and completion of the NHTSA/IACP Instructor Development Course (NHTSA, 2018).

Other Considerations:

Drug-impaired driving enforcement shares many of the same issues cited under drug-impaired-driving laws (see Drug-Impaired-Driving Laws – Other Considerations). For example, drug-impaired driving enforcement has equity implications if people of color are disproportionately stopped, evaluated for drug impairment, arrested, convicted, and penalized; therefore, drug-impaired driving enforcement activities should be monitored for potential racial and ethnic bias. If bias is found, prompt action should be taken.

[1] The seven drug categories established by the DEC are cannabis, CNS depressants, CNS stimulants, dissociative anesthetics, hallucinogens, inhalants, and narcotic analgesics (NHTSA, 2018b).