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What Tests are Used to Determine Impairment in Marijuana DUI Cases?

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How Can Officers Tell if a Person is Driving Under the Influence of Marijuana?

Despite the legalization of marijuana in Colorado for both medicinal and recreational purposes, driving under the influence of marijuana remains illegal and can result in serious consequences.

The state’s laws aim to deter motorists from driving while impaired by imposing strict penalties and fines. The legal framework includes specific limits for THC levels in the bloodstream and emphasizes the importance of enforcing laws against impaired driving to protect public safety.

However, the reliability of the methods specifically used to determine marijuana impairment is still a subject of heated debate. Currently, determining marijuana impairment in Colorado drivers may involve a combination of field sobriety tests (FSTs), oral fluid and blood testing, and officer observations. If you’ve been charged with a marijuana DUI, it’s vital to contact a knowledgeable Colorado DUI defense lawyer who can evaluate the circumstances of your arrest and uphold your legal rights.

What Are Colorado’s Marijuana DUI Laws?

Under C.R.S. 42-4-1301, a motorist can be charged with a marijuana DUI if, due to marijuana use, they are substantially incapable, mentally or physically, of safely operating their vehicle. The penalties for a first conviction of marijuana DUI include:

  • Jail time ranging from five days to one year.
  • Fines between $600 to $1,000.
  • Additional penalties may apply for aggravating circumstances like prior convictions, potentially leading to felony charges with up to two years in prison, probation, and fines up to $500,000.

Legal Limits and Testing

Colorado sets a legal limit of five nanograms of delta-9-THC per milliliter of blood for prosecuting DUI cases involving marijuana. However, the accuracy and practicality of THC testing have been questioned due to THC’s fat-soluble nature, which can lead to a prolonged presence in the bloodstream even after impairment has subsided. Critics argue that the effects of five nanograms of THC are not scientifically quantifiable and do not provide a sufficient basis for impairment.

How Do Law Enforcement Officers Test For Marijuana Impairment?

To determine impairment in marijuana DUI cases, law enforcement officers typically use a combination of tests and observations. There is currently no universally accepted breath test for marijuana DUIs, and the reliability of existing breath tests for detecting THC is questionable. Here’s a detailed look at the currently accepted methods of testing for marijuana impairment:

Field Sobriety Tests (FSTs)

Officers may conduct Standardized Field Sobriety Tests (SFSTs) to assess a driver’s physical and cognitive abilities. These tests can include:

  • Eye examinations: Checking for signs of impairment through eye movements.
  • Physical coordination tests: These may include standing on one leg or performing a walk-and-turn test. The tests are designed to assess balance, attention, and motor skills.

However, it’s important to note that while these tests are effective for detecting alcohol impairment, research indicates that their reliability for detecting marijuana impairment is questionable.

Oral Fluid, Blood, and Other Tests

If an officer suspects a driver has drugs in their system during a DUI stop, they can demand an oral fluid sample. The sample is taken with a swab and tested using Approved Drug Screening Equipment (ADSE), which can detect the presence of THC (the main impairing chemical in cannabis) and other drugs. Unfortunately, saliva testing may produce positive results for weeks after THC ingestion. A positive test can lead to further testing at a police station, including attention tests, physiological evaluations, and blood or urine tests.

Blood tests can detect THC and its metabolites. However, they do not reliably indicate impairment due to the variable effects of THC on individuals and the fact that THC can remain detectable long after its psychoactive effects have worn off. The detection window for THC in blood can be over 12 hours, and for frequent users, it can be detectable for up to a week. Individuals with higher body fat percentages may show signs of THC in their blood for much longer than others because THC is stored in fat.

Urine tests can also detect marijuana use, but like blood tests, they face challenges in accurately determining impairment at the time of driving. Urine testing can detect marijuana in casual users up to three days later and in heavy users for ten days or more. Hair samples can also detect marijuana consumption but are not useful for DUI cases because it takes about a week for THC to appear in hair follicles.

Officer Observations

Officers may rely on observations such as erratic driving, red eyes, muscle tremors, or unusual speech patterns to establish reasonable suspicion. If a driver fails an SFST or provides a positive oral fluid sample, they may be arrested and subjected to further testing to corroborate the observations.

The testimony of the arresting officer is frequently used as evidence in DUI cases involving marijuana. Officers may report observations such as the smell of marijuana, the presence of paraphernalia, distracted behavior, dilated pupils, or other signs of impairment. Some officers are trained as drug recognition experts (DREs) and have taken courses on drug detection, although the requirements for DRE certification vary by state.

How Can an Experienced DUI Attorney Assist You?

A marijuana DUI conviction in Colorado can result in severe ramifications, including fines, jail time, and a lasting mark on your criminal record. However, many doubts still exist about the reliability of the tests used to determine marijuana impairment. With so much on the line, it’s essential to seek the opinion of an experienced DUI-D defense lawyer who can evaluate the circumstances of your arrest and determine your legal options for fighting the charges. Contact Liberty Law Center today at 719-602-7381 to request a free consultation.

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