Drug-Impairment Methods of Detection

Did You Know?
Driving under the influence is difficult to prove when the driver is impaired by drugs other than alcohol.

Although driving under the influence of drugs (DUID) has increased significantly over the years (see Prevalence page), driving under the influence is difficult to prove when the driver is impaired by drugs other than alcohol. Polysubstance use or driving under the influence of multiple drugs can have a multiplicative effect on impairment (see Polysubstance section) and significantly increases crash risk. Additionally, research has shown that combining alcohol and Cannabis/Marijuana can result in greater impairment than when used alone (see Dangers section). Drug testing needs to be increased among impaired drivers to adequately deal with this increased risky driving behavior.

Polysubstance-use Impaired driving

According to the International Association of Chiefs of Police (IACP), in 2018 of the 863 drug recognition evaluations performed by drug recognition experts (DREs), 426 cases likely involved polydrug impairment.

There is no standardized testing technology for substances other than alcohol. A toxicology test (drug test or “tox screen”) identifies traces of drugs in blood, urine, hair, sweat, or saliva. However, drugs rapidly metabolize and by the time a test has been taken, the drug levels may  have decreased, therefore not demonstrating the concentration levels at the time of driving. Chemical evidence in the blood dissipates quickly but driver impairment can last for hours.

Common drugs that are tested for impairment include:

  • Marijuana
  • Cocaine
  • Opioids (Codeine, morphine, heroin, hydrocodone, hydromorphone, oxycodone, oxymorphone)
  • Phencyclidine (PCP)
  • Amphetamines, Methamphetamines, and Methylenedioxymethamphetamine (MDMA)

Testing and Technology

Chemical research

Testing methods to determine drug use include blood, urine, oral fluid (primarily saliva), sweat, and hair samples. A toxicology test cannot identify addiction issues, or the amount of drug used or when. A toxicity test is only able to tell if certain drugs are (or have recently been) in the body. Long after a user inhales, injects, or ingests, legal and illegal drugs stay in the body.

Drug Screen Blood Sample

Blood Testing

Blood testing is considered the standard for identifying the presence of drugs with DUID traffic stops. The United States Supreme Court case Missouri v. McNeely, 569 U.S. 141 (2013) ruled that police must generally obtain a warrant before subjecting a drunken-driving suspect to a blood test, and that the natural metabolism of blood alcohol does not establish a per se exigency that would justify a blood draw without consent. Usually blood is drawn from a vein the arm. The sample will then be tested at a lab. Lab results are mailed to the officer and added to the arrest report. These results can be used as evidence when determining a DUID conviction.

Urine Testing

A urine specimen is collected and sent to a certified laboratory for analysis to determine drug use. Here lab results are again mailed to the officer and added to the arrest report. These results can be used as evidence when determining a DUID conviction.

Oral fluid girl with stick in mouth

Oral Fluid Testing

Oral fluid (OF) testing is increasing in use by states since the technology is minimally invasive, more economical than traditional testing methods and has been deemed reliable in identifying recent drug use. Currently oral fluid testing is not considered evidentiary and is only used as a screening tool.

Oral fluid testing is used for preliminary screening by law enforcement during a roadside drug impaired driving investigation which identifies recent use and various classes of drugs. OF  testing has been considered in various states for its fast (within 10 min) and accurate results and because use does not require a warrant (as with blood draws). Use of OF is usually conducted after an officer has concluded a driver is impaired and a Standard Field Sobriety Test (SFST) has been conducted. Oral fluids allows for appropriate allocation of limited resources since these are used as a screening device to identifying where further are needed for proof of drug impairment. Oral fluids only show the presence of drug use.

Technology used to test oral fluids for drugs

According to the National Conference of State Legislatures, currently, at least 23 states authorize some form of oral fluid testing at roadside screening sites or for evidentiary purposes in court cases to show drug presence or recent drug use. For an interactive map of state oral fluid laws click here. Most of these states, however, have not yet established active oral fluid testing programs.

Other Testing Devices

There are several devices on the market that can be used to screen for drug use. Several have been created to be used in the workplace for companies that employ fleet and other drivers.

The National Safety Council (NSC) has recently conducted an Impairment Environmental Scan Project with other nonprofit organizations to investigate the need for a new workplace impairment training course and the efficacy of impairment detection technologies (for example, psychomotor vigilance testing) used to ensure workplace safety. During the course of this project, 10 devices were reviewed and feedback was provided by an expert advisory panel regarding potential and barriers to implementation. This project is currently still in progress; however, detailed information on each of these devices included in this study are currently available by clicking on their links below. Please note: NSC has not formally vetted these technologies for employer use and has not publicly posted any information on this project.

The devices included:

  • MFP100 Impairment Screen
    SafetyScan detects psychomotor impairment caused by alcohol, drugs, and cognitive fatigue via a tracking test of involuntary eye movement. An infrared camera tracks this eye movement and the test result is analyzed using a proprietary algorithm. The results of the current test are compared to a previously established baseline. The result of this comparison is either PASS (meaning no impairment is found) or REFER (meaning impairment has been found). Next steps following a REFER are dictated by each company’s HR policies.
  • AlertMeter
    The AlertMeter® alertness test is a fast and easy graphic test whose interface displays different shapes that the user must identify accurately and quickly. The patented design does not simulate any particular job function but challenges a number of key brain functions that are necessary for all jobs. AlertMeter looks at accuracy, situational awareness, and reaction time.
  • DRUIDapp
    The DRUIDapp measures cognitive abilities and performance on tasks related to driving, operating heavy machinery, and making critical decisions. DRUID acts like a video game, but is a sophisticated measurement tool for cognitive impairment. The DRUIDapp is designed to measure cognitive and behavior impairment of any cause including consumption of drugs, alcohol, lack of sleep, or injury.
  • PVT-192
    The PVT-192 Psychomotor Vigilance Task Monitor provides a hand-held, self-contained system to record and store reaction time measurements. The PVT test, combined with easy-to-use React software, has proven to be a valuable tool wherever measures of performance or sleepiness are needed.
  • Workplace Impairment Test
    The Workplace Impairment Test (WIT) is comprised of 4 divided attention psychophysical tests as a tablet-based app, which is user friendly. It starts with general questions to determine if the subject is in need of medical attention. Next, are the psychophysical and eye tests. The examiner will use check boxes to score the performance on the tests, and our proprietary algorithm will determine if the subject is “likely impaired,” “not likely impaired,” or “unsure, further testing suggested.”
  • PVT WorkFit
    PVT WorkFit is scientifically validated and widely recognized as the gold standard assay of neurobehavioral alertness. Employees take a 10-minute Psychomotor Vigilance Test (PVT) as part of a fitness for work assessment. Clinicians can access test results instantly along with advanced analytics and normative data to aid interpretation.
  • SeeingMachines (formerly Guardian)
    Human factors science was used to create artificial intelligence (AI) technology that observes the driver’s attention – reliably, unobtrusively, and in real time – and intervenes seamlessly when necessary. The algorithms can robustly, accurately and in real-time, measure a driver’s visual attention to their environment, assess their degree of drowsiness, and ultimately detect if the driver has passed a threshold of risk. Mitigating the risk is then enacted through intelligent alerting of the driver as well as informing a vehicle’s wider control systems.
  • ExceleRATE
    ExceleRATE is an all-in-one commercial driver risk management program that features a comprehensive assessment that looks at the various skills critical for safe driving. ExceleRATE assigns each driver, easy-to-understand, risk factors based on medications or medical conditions that may have affected the specific mental abilities necessary for safe operation of a motor vehicle. It looks at actual behind-the-wheel performance to identify where and how significant skills may be affected. ExceleRATE provides managers the tools to make quick and informed decisions about safety. ExceleRATE is comprised of two assessments, VITALS and CORE. VITALS is executed in-office and designed to assess critical cognitive skills, while CORE is designed to break down which driving errors are caused by cognitive issues and which are the result of bad habits. 
  • SmartEye
    Smart Eye’s Driver Monitoring System (DMS) solution offers eye tracking software for integration in passenger cars and other vehicles to facilitate better safety and other functions that improve the user experience. By studying a person’s eye, face and head movements, Smart Eye’s interior vehicle algorithms can draw conclusions about a person’s alertness, attention and focus. Today, car manufacturers that have included the technology include German premium car manufacturers as well as one of China’s largest original equipment manufacturers, Geely. Smart Eye is the market leader within the Automotive industry, paving the way for high performance reliability, precision, optimized costs, and availability. The company’s research instruments offer unparalleled performance in complex, real-world situations, paving the way for new insights in aerospace, automotive, aviation, psychology, communication, neuroscience, medicine, and clinical research.
  • FIT 2000
    The hardware device performs eye tracking to measure changes in pupil diameters, latency, and speed to determine an individual’s level of risk. Individuals are required to take 10 initial tests to create a baseline and then each test is compared to the baseline to determine one’s level of risk.

For questions regarding this project, please contact Claire Stroer at Claire.Stroer@nsc.org.

Hand in glove holds a jar with urine analysis where mark a positive test for doping or drug

Get the Facts!

  • Testing methods to determine drug use include blood, urine, oral fluid (primarily saliva), sweat, and hair samples.
  • A toxicology test cannot identify addiction issues, or the amount of drug used or when. A toxicity test is only able to tell if certain drugs are (or have recently been) in the body.
  • Long after a user inhales, injects, or ingests, legal and illegal drugs stay in the body.
  • Traces of opiates can be found in the urine a few days after they are taken.
  • Signs of marijuana in blood, urine, hair and oral fluid can last up to three weeks.
  • Oral Fluid (primarily saliva) is collected with an absorptive device placed in the mouth. The device is then sent to a laboratory for testing to obtain results.
  • OF testing reflects free drugs in the blood.
  • OF can be collected more quickly following a traffic incident which is a more reliable indicator of drugs present in the body at the time of the stop.
  • Active drugs detected in saliva (e.g., THC or cocaine) are indicative of recent intake, not historical use.
  • States with active oral fluid programs include:
    • Alabama, which initially conducted a pilot program that transitioned to a permanent oral fluid toxicology program in both screening and evidentiary capacities.
    • Michigan is conducting a statewide oral fluid pilot program that was extended to Sept. 30, 2020.
    • Illinois has a pending bill (HB 5194) that would establish an oral fluid roadside analysis pilot program for one year.
  • In 2019, Kansas, North Dakota and South Dakota amended their laws to include testing of saliva, oral fluids or other bodily substances.
  • This year (2020), New York (AB 968/SB 321) has a pending bill that would add saliva tests to the chemical tests a driver must submit to at an officer’s request.
  • Electronic warrants or the equivalent may be needed to assure that a blood or urine sample can be obtained relatively quickly.

Law Enforcement Programs

Male police officer with dog patrolling city street

ARIDE program

The Advanced Roadside Impaired Driving Enforcement (ARIDE) program was developed by the National Highway Traffic Safety Administration (NHTSA) with input from the International Association of Chiefs of Police (IACP), Technical Advisory Panel (TAP), and the Virginia Association of Chiefs of Police.

ARIDE is intended to bridge the gap between the Standardized Field Sobriety Testing (SFST)  and Drug Evaluation and Classification/ Drug Recognition Experts (DEC/DRE) Programs by providing officers with general knowledge related to drug impairment and by promoting the use of DREs in states that have the DEC Program. The ARIDE course trains law enforcement officers to observe, identify and articulate the signs of impairment related to drugs, alcohol, or a combination of both, in order to reduce the number of impaired driving incidents as well as crashes which result in serious injuries and fatalities.

Police Officer - Eye Coordination

Drug Evaluation and Classification (DEC/DRE) Program

A drug recognition expert or drug recognition evaluator (DRE) is a police officer trained to recognize impairment in drivers under the influence of drugs other than, or in addition to, alcohol. DEC programs are active in all 50 states and internationally.

The International Association of Chiefs of Police (IACP) coordinates the International Drug Evaluation and Classification (IDEC) Program with support from the National Highway Traffic Safety Administration (NHTSA). DEC Program also educates prosecutors and toxicologists on the DRE process and the drug categories to provide a better understanding of the science behind the determination of driver impairment when used as evidence in a court hearing.

Once called to the scene of a suspected drug impaired driver, the DRE will conduct a 12-step evaluation usually in a controlled environment to identify potential driver impairment. The DRE will identify potential impairment by seven classifications of drugs:

  • Central Nervous System (CNS) Depressants: Valium, Librium, Xanax, Prozac, and Thorazine), GHB (gamma hydroxybutyrate), Rohypnol, and many other anti-depressants (e.g., Zoloft, Paxil).
  • CNS Stimulants: cocaine, “crack” cocaine, amphetamines, and methamphetamine (“crank”).
  • Hallucinogens: LSD, peyote, psilocybin and MDMA (Ecstasy).
  • Dissociative Anesthetics: PCP, Ketamine, and Dextromethorphan, an active ingredient in some over-the-counter cold medicines.
  • Narcotic Analgesics: e.g., opium, codeine, heroin, demerol, darvon, morphine, methadone, Vicodin, and oxycontin.
  • Inhalants: Toluene, plastic cement, paint, gasoline, paint thinners, hair sprays, and various anesthetic gases.
  • Cannabis/Marijuana. The active ingredient in cannabis is delta-9 tetrahydrocannabinol, or THC. This category includes cannabinoids and synthetics like Dronabinol.
Pulled over by police car

Get the Facts!

  • The SFST program trains officers to identify and assess drivers suspected of being under the influence of alcohol.
  • The DEC/DRE program provides more advanced training to evaluate suspected drug impairment.
  • The SFST assessment is typically administered at roadside during a traffic stop or sobriety checkpoint.
  • A Drug Recognition Expert (DRE) officer trained through the DEC program conducts a 12-step evaluation in a more controlled environment such as a jail or a detention facility.
  • ARIDE was created to address the gap in training between the Standardized Field Sobriety Testing (SFST) and the Drug Evaluation and Classification (DEC/DRE) Program.
  • ARIDE graduates must demonstrate proficiency with the SFST requirement. The ARIDE program stresses the importance of the signs and symptoms of the seven drug categories.
  • A DRE conducts a detailed, diagnostic examination of persons arrested or suspected of drug-impaired driving or similar offenses. Based on the results of the drug evaluation, the DRE forms an expert opinion on the following:
    • Is the person impaired? If so, is the person able to operate a vehicle safely? If the DRE concludes that the person is impaired…
    • Is the impairment due to an injury, illness or other medical complication, or is it drug-related? If the impairment is due to drugs…
    • Which category or combination of categories of drugs is the most likely source of the impairment?
  • DREs conduct their evaluations in a controlled environment, typically at police precincts, intake centers, troop headquarters or other locations where impaired drivers are transported after arrest.
    • The drug evaluation is not normally done at roadside and is typically a post-arrest procedure.
  • In most cases, the DRE will be called upon to conduct the evaluation after the driver was arrested by another officer.
  • A DRE is requested to assist in the investigation because of his or her special expertise and skills in identifying drug impairment.
  • The DRE drug evaluation takes approximately one hour to complete.
  • The DRE evaluates and assesses the person’s appearance and behavior.
  • A DRE carefully measures and records vital signs and makes precise observations of the person’s automatic responses and reactions.
  • A DRE administers carefully designed psychophysical tests to evaluate the driver’s judgment, information processing ability, coordination and various other characteristics.
  • A DRE will systematically consider everything about the person that could indicate the influence of drugs.

Admissibility in Court

Justice sign on a Courtroom Building.

Oral Fluids

Laboratory testing of oral fluid specimens incorporates validated protocols similar to currently accepted practices for blood testing. Therefore, oral fluids have been considered extremely reliable and admissible.

On-site oral fluid devices vary widely. Oral fluid devices are mostly used as screening devices where additional specimens will be collected for laboratory testing. Therefore, admissibility is not a significant issue. In Maryland v. King, the U.S. Supreme Court recognized that oral fluid DNA testing is far less intrusive, dangerous, and painful than blood testing, and that taking a cheek swab to verify a person’s identity through DNA testing is a legitimate police booking procedure and permissible under the Fourth Amendment.

Drug Evaluation and Classification (DEC)/Drug Recognition Expert (DRE) Program

The DRE/DEC program has been considered an effective although imperfect approach to detect drug impairment. On February 3, 2000, The Supreme Court of Washington, En Banc. STATE of Washington, Appellant, v. Michael BAITY and Edward Arnestad, Respondents Case No. 66876-found that “DRE evidence is admissible under Frye because it is generally accepted in the relevant scientific communities.  A properly qualified expert may use the 12-step protocol and the chart of categories of drugs to relate an opinion about the presence or absence of certain categories of drugs in a suspect’s system.”

However, because of the challenges previously presented identifying impairment by drugs when driving, there are some jurisdictions that may still challenge the DRE program despite its validations as stated above. More research is needed in this regard.

What Employers Can Do