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Marijuana DUI Defense Attorney

Driving under the influence of Marijuana and Blood Tests

By: Lain A. Lawrence - DUI Defense Attorney Oct. 24, 2024

In 2012, Colorado legalized recreational marijuana. This was mostly a good decision by the state. Prosecuting people for marijuana possession was exceedingly unpopular. A consistent trend throughout the country showed individuals in favor of legalization. 

Additional regulations concerning driving under the influence of marijuana follow legalization. Advances in testing resulted in added police procedures when investigating a suspected Driving under the Influence of Drugs ("DUID"). 

A DUI involving THC is complex when compared to a driving under the influence of alcohol case. Simultaneously, it is substantially easier to get convicted of such a charge. Consulting with a Colorado DUI attorney is always advisable if facing these cases.

What is driving under the influence in Colorado?

Driving under the influence is operating a motor vehicle while under the influence. Operation of a vehicle means driving or being in actual physical control of the vehicle. Under the influence means a person is substantially incapable of safely operating their vehicle because of intoxication.

Intoxication can be a result of alcohol or drugs. In some cases, it can be a combination of both. With respect to THC, authorities presume anyone with 5 nanograms per milliliter to be under the influence.

Colorado law has a lesser included offense of driving while ability is impaired. Driving while impaired means operating a vehicle when a person's ability to drive is affected, even a little. Unlike alcohol, the law does not provide a limit on what is impaired to the slightest degree of THC.

How does Law Enforcement Test for Marijuana during a DUI?

Police investigation of a DUI focuses on the entire interaction with the defendant. Police will start their investigation by looking at signs of impaired driving. This could be anything from weaving to speeding.

Upon initial contact, officers look for any indicia of intoxication. This includes bloodshot and watery eyes, slurred speech, and the odor of marijuana. Police also question individuals about possible impairment and use of marijuana.

During these interactions, questioning is often non-confrontational. The idea is to obtain cooperation by answering questions.

If the law enforcement officers establish probable cause, they will offer a standard field sobriety test. The SFST has three main components, a horizontal gaze nystagmus test (“HGN”), walk-and-turn test, and one-legged stand test. When investigators look for possible marijuana, they offer a fourth modified Romberg test.

The SFST are problematic when applied to cases involving THC. The impact of THC and alcohol on a person’s ability to perform these tests varies widely. 

For example, the SFST tests were created by the National Highway Traffic Safety Administration. Their research found that marijuana would not impact an individual’s optic nerves. Alcohol will affect a person’s optic nerves and cause involuntary jerking, or nystagmus, which is observed during an HGN test. The lack of impact means that nystagmus should not occur when only weed is in a person’s system.

If a person fails to perform as a sober individual, the authorities will arrest the driver and request a blood test. 

How does a blood test work in a THC DUI?

The Colorado express consent statute requires a defendant to submit to chemical testing if requested by law enforcement. Law enforcement requires probable cause to believe a person is driving under the influence before requesting a test. The test can be of a person’s breath or blood. However, it can be limited to only blood if drugs are the sole suspected cause of intoxication.

If a blood test is performed, two vials of blood are collected. One vial is for the cops, and the other is for the defendant to retest if requested. They typically collect the blood within two hours of driving.

A certified toxicologist then receives the blood. The toxicologist will perform an initial test to determine whether cannabinoids are present. Cannabinoids are a chemical compound associated with marijuana. These can include several types of metabolites found in someone who smokes marijuana.

After this initial test, researchers will conduct a second test to determine the type and levels of specific cannabinoids. The key metabolite is delta 9-tetrahydrocannabinol. This is the active metabolite in marijuana that causes the person to be intoxicated. A Regular smoker has inactive metabolites in their blood as well.

Individuals are free to refuse a blood test. As mentioned above, authorities have already arrested the person and charged them with DUI. The refusal's strength or weakness depends on the totality of the case.

How is THC different from Alcohol in Colorado?

Absorption is one of the primary differences between alcohol and weed. Marijuana is typically smoked, and the drug is absorbed through the lungs. This results in a quicker metabolism as the metabolites enter the bloodstream quicker.

Considering the amount of THC in an average joint, a person will quickly be above the legal limit after consumption. Arguments concerning raising THC levels in the blood are usually not workable.

The rate of elimination is also different. The average rate at which a body eliminates alcohol is about one drink per hour or .015 grams per 100 milliliters. 

Marijuana is eliminated in half-lives. This means a person that has ten nanograms of THC in their blood will have about five nanograms after an hour.

Finally, smoking causes a significant odor. This is crucial because smell is a primary tool used by officers during investigations. Smoke will stick to a defendant and their surroundings. 

Smoking in a vehicle is also extremely problematic as the smell could potentially linger for several days. This becomes a problem if officers smell burnt marijuana a person is likely getting arrested.

SPEAK WITH A THC DUI DEFENSE ATTORNEY TODAY

A DUI can seriously impact a defendant’s life. It may seem simple and straightforward, but this kind of case can be complicated. Talking to a DUI defense lawyer who knows the details of a DUI case is important. This helps create the best defense strategies.  

With 10 years of experience, our firm routinely handles DUI Cases and continues to study THC and its impact. We are ready, willing, and able to provide you with the representation you deserve. We offer free consultations and flexible payment plans. 

Our goal is to offer strong support to anyone who needs it. We do not turn away any defendants due to budget issues. The Experienced DUI lawyers at the Lawrence Law Firm are here to help.

The trial attorneys at the Lawrence Law Firm often handle cases about field sobriety tests and DUI arrests. We are familiar with what impairs driving, and we will fight. We have experienced reduced charges, including reckless driving.

Our legal representation routinely represents clients in Arapahoe, Denver, Adams, Jefferson, and any metro criminal case. If you have DUI charges, request an appointment with our officer. We do offer afternoon and weekend appointments.