Marijuana DUI Test (2024): Can They Prove You’re High?

What You Need to Know About Marijuana Use and Driving

According to the U.S. Centers for Disease Control and Prevention (CDC), driving laws regarding impairment aren’t limited to alcohol; they also encompass drugs like marijuana [1]. This substance can significantly affect your ability to drive safely by impairing essential skills such as reaction time, decision-making, coordination, and perception.

Studies have shown an association between acute marijuana use and car crashes, but more research is needed. It is difficult to connect the presence of marijuana or concentration of tetrahydrocannabinol (THC), the compound responsible for marijuana’s psychoactive properties (the “high”), to impairment in driving performance for an individual person. Studies have shown that the use of multiple substances (such as marijuana and alcohol) at the same time can increase impairment –  Agency stated.

How Do the Police Prove Impairment in Marijuana DUI Cases?

According to the LACL, in many DUI cases, the arrest process begins with a driver being pulled over by the police for a traffic violation [2]. The driver’s behavior during the stop, such as weaving, running stop signs, or red lights, can be used as evidence of impairment. However, some arrests occur without apparent signs of impaired driving, such as when the driver is stopped for an equipment violation or at a DUI checkpoint.

During the stop, the officer will interact with the driver and may notice signs of marijuana use, such as the smell of marijuana, physical symptoms of intoxication, or the driver’s admission of recent marijuana use.

The officer may call a Drug Recognition Expert (“DRE”) officer to assist in the investigation. These officers receive specialized training in recognizing the symptoms of drug intoxication. The driver will be asked to participate in a series of field sobriety tests designed to determine impairment. The officer’s notes regarding the driver’s performance on these tests can be used as evidence of impairment – LACL stated.

What is the Romberg Test for Marijuana?

According to Sean Black of Black Law Offices, officers who have completed Standardized Field Sobriety Testing (SFST) training may undergo further training in Advanced Roadside Impaired Driving Enforcement (ARIDE) or Drug Recognition Evaluation (DRE). Both ARIDE and DRE training include the Modified Romberg Test (MRB), which is used to assess a driver’s level of impairment [3]. However, some critics argue that the MRB, like many roadside testing methods, is flawed and biased in favor of supporting the officer’s decision to arrest.

An officer conducting a Modified Romberg Test is looking for three indicators: time estimation, tremors, and swaying. These are all being looked for a the same time. Tremors may be eyelid or body or muscle tremors. Sway may be front-to-back, side-to-side or circular/rotational. Time sense is measured by the subject’s estimation of thirty seconds as compared to an actual clock. In addition, the test is described as a divided attention test since it requires the subject to follow a set of instructions given before the onset of the test, the agency stated.

The test consists of two stages: instruction and balancing. During the instruction stage, the driver is instructed to stand with feet together and arms down at their sides. They are told to maintain this position while receiving instructions and not to begin the balancing stage until instructed to do so. The officer should ensure that the driver understands the instructions before proceeding.

In the balancing stage, the driver is told to tilt their head back slightly, close their eyes, and estimate the passage of thirty seconds. Once they believe thirty seconds have passed, they are instructed to tilt their head forward, open their eyes, and say “Stop.” The officer observes the subject for tremors and sway while monitoring the time. If the person takes 90 seconds or more, the officer will end the test. After the test, the officer may ask the person to estimate how much time has passed to confirm their perception of time.

In evaluating the test results, time estimates within five seconds of the target are considered normal. Times less than 25 seconds or greater than 35 seconds are considered significant and may indicate the presence of substances affecting the internal clock. Swaying is rated based on the degree of movement from the center point, and tremors are assessed based on their location and type, which can indicate the presence of certain substances in the system.

Marijuana DUI Statistics

• In 2018, an estimated 10,511 alcohol-impaired driving deaths occurred.
• The contribution of marijuana and other illicit drugs to impaired driving deaths is unknown.
• In 2014, 12.4% of people aged 16–25 reported driving under the influence of alcohol, and 3.2% reported driving under the influence of marijuana.
• The effects of illicit substances and psychoactive drugs on driving are less understood compared to alcohol.
• In 2018, 12 million (4.7%) U.S. residents reported driving under the influence of marijuana in the past 12 months, and 2.3 million (0.9%) reported driving under the influence of illicit drugs other than marijuana.
• Driving under the influence was more prevalent among males and persons aged 16–34 years.

Source: CDC [4].

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• 2023 Colorado Psychedelic Mushroom Law
• Am I Allowed to Drive After Taking CBD?

FAQs

What types of tests are used to detect marijuana impairment in drivers?

Several types of tests are used to detect marijuana impairment, including blood tests, which measure the concentration of THC in the bloodstream; saliva tests, which can detect recent marijuana use; and urine tests, which identify the presence of THC metabolites. Field sobriety tests may also be used to assess impairment based on physical and cognitive responses.

How accurate are marijuana DUI tests?

The accuracy of marijuana DUI tests can vary. Blood tests are considered the most accurate for detecting THC levels, but they may not directly correlate with impairment. Saliva tests are less invasive but may be less reliable, especially for frequent users. Urine tests can detect THC metabolites long after impairment has subsided, making them less useful for determining current intoxication.

Can a person be charged with a DUI for marijuana even if they are not impaired?

Yes, a person can be charged with a DUI for marijuana even if they are not impaired, depending on the state’s laws. In zero-tolerance states, any detectable amount of THC in the system can lead to a DUI charge, regardless of whether the driver shows signs of impairment.

If you feel affected by any of these matters, contact our criminal defense attorney today.

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References:

1. https://www.cdc.gov/marijuana/health-effects/driving.html
2. https://www.losangelescriminallawyer.pro/how-can-the-police-prove-impairment-in-dui-marijuana-cases.html
3. https://www.duiguru.com/the-modified-romberg-test-why-you-should-not-do-it
4. https://www.cdc.gov/mmwr/volumes/68/wr/mm6850a1.htm