Defenses and Strategies for DUI Marijuana Charges: A Legal Guide with Case References
As marijuana legalization spreads, so too have DUI charges related to cannabis use. While most people are familiar with DUI charges involving alcohol, marijuana DUIs present unique challenges and complexities. In contrast to alcohol, where impairment can be measured by a standard Blood Alcohol Content (BAC) level, there is no universally accepted level of THC (the psychoactive compound in marijuana) that constitutes impairment.
This blog will explore common defenses and strategies that attorneys use to fight marijuana DUI charges, with references to real cases that illustrate how these defenses have worked in court.
Understanding Marijuana DUIs
Before diving into defenses, it’s essential to understand what constitutes a DUI for marijuana. Generally, a marijuana DUI occurs when a person is operating a vehicle while impaired by cannabis. Law enforcement uses various methods to detect impairment, including field sobriety tests, blood or urine tests to measure THC levels, and observations of behavior. However, there are major flaws in determining marijuana impairment, leading to opportunities for defense.
Unlike alcohol, THC stays in the bloodstream for days or even weeks after use, making it difficult to establish actual impairment at the time of driving. As a result, marijuana DUI charges can be more subjective, often relying on circumstantial evidence.
Top Defenses for Marijuana DUI Charges
1. Challenging the Legality of the Traffic Stop
A common defense strategy in any DUI case is to challenge the legality of the initial traffic stop. Under the Fourth Amendment, law enforcement officers must have reasonable suspicion to pull a driver over. This means the officer must have observed behavior suggesting the driver committed a traffic violation or crime.
If the stop is deemed unlawful, any evidence obtained during the stop—including field sobriety tests and blood/urine tests—may be suppressed.
Case Reference: In People v. Brendlin, 551 U.S. 249 (2007), the U.S. Supreme Court held that evidence obtained after an illegal stop cannot be used in court. This case underscores the importance of lawful police conduct during DUI investigations. If the officer lacked reasonable suspicion, the evidence from the stop could be excluded, leading to dismissal of the charges.
2. Questioning the Validity of Field Sobriety Tests (FSTs)
Field sobriety tests are often used to detect impairment, but these tests are subjective and have no specific correlation to marijuana impairment. Common tests, such as walking in a straight line or standing on one leg, are designed to detect alcohol impairment and can be unreliable for marijuana DUIs.
Physical factors like anxiety, fatigue, or a pre-existing medical condition may cause someone to fail an FST without being impaired by marijuana. An attorney can argue that the results of these tests should not be relied upon to determine impairment by marijuana.
Case Reference: In People v. McKown, 236 Ill. 2d 278 (2010), the Illinois Supreme Court questioned the reliability of FSTs as a sole indicator of impairment, stating that their accuracy can be influenced by factors unrelated to drug use. This case shows how FSTs can be challenged when used as evidence in DUI cases.
3. Challenging THC Blood Test Results
One of the most powerful defenses in a marijuana DUI case is challenging the accuracy and reliability of the blood or urine tests used to measure THC levels. Unlike alcohol, where BAC levels are directly linked to impairment, there is no scientific consensus on how THC levels correspond to driving impairment.
THC can stay in the bloodstream long after the psychoactive effects have worn off. This means a driver could test positive for THC even if they were not impaired at the time of driving. Attorneys often call into question:
- Testing methods and protocols
- Chain of custody issues (i.e., whether the blood sample was handled properly)
- Laboratory errors in processing and analyzing the sample.
Case Reference: In State v. Shupe, 516 P.3d 92 (Utah Ct. App. 2022), the Utah Court of Appeals reversed a marijuana DUI conviction after finding that the blood test results were unreliable due to improper laboratory procedures. This case illustrates the importance of scrutinizing how blood tests are conducted and analyzed in marijuana DUI cases.
4. Arguing Residual THC Levels (Non-impairment)
One of the key issues in marijuana DUI cases is the fact that THC can remain in the bloodstream for days or even weeks after use, long after its impairing effects have subsided. This is particularly problematic for medical marijuana users who may have trace levels of THC in their system at all times, even when they are not impaired.
A strong defense is to argue that while the driver had THC in their system, it was residual and not indicative of impairment at the time of driving.
Case Reference: In Commonwealth v. Etchison, 916 N.E.2d 690 (Mass. 2009), a driver’s marijuana DUI charge was dismissed after the court found that the prosecution could not prove the driver was impaired at the time of the arrest. The court noted that THC levels alone were not sufficient to establish impairment without additional evidence of poor driving or behavior.
5. Medical Marijuana Defense
For drivers who are legally using medical marijuana, it is important to demonstrate that they were using marijuana in accordance with state law and that they were not impaired at the time of driving. While having a medical marijuana card does not grant immunity from DUI charges, it can serve as part of a defense strategy, especially if there is a lack of evidence proving impairment.
Medical marijuana users can argue that their THC levels reflect legal, prescribed use rather than illegal intoxication. However, the defense must still address any claims that the driver was impaired.
Case Reference: In People v. Feezel, 486 Mich. 184 (2010), the Michigan Supreme Court ruled that medical marijuana users cannot be convicted of a DUI simply because of the presence of THC in their system. The state must prove impairment. This case set an important precedent for medical marijuana patients who drive and are later charged with a DUI.
6. Lack of Evidence of Impairment
A key element in any DUI case is proof that the driver was actually impaired while operating the vehicle. If the prosecution relies solely on THC levels and does not present additional evidence of erratic driving or impairment (such as failing a field sobriety test), the defense can argue that there is insufficient evidence to prove the driver was impaired.
Case Reference: In People v. Koon, 494 Mich. 1 (2013), the Michigan Supreme Court held that the presence of THC in a driver’s blood was not enough to sustain a DUI conviction without additional evidence of impairment. The court emphasized that the prosecution must prove the driver was actually impaired while operating the vehicle, not just that they had THC in their system.
Conclusion: Defending Against a Marijuana DUI
Marijuana DUI cases are complex and present unique legal challenges, particularly because there is no clear scientific standard for determining impairment based on THC levels. However, as more states legalize marijuana, courts are increasingly examining the reliability of tests and the evidence needed to prove impairment.
If you are facing a marijuana DUI charge, it is crucial to consult with an attorney experienced in DUI defense. There are numerous defenses available, from challenging the legality of the stop to questioning the validity of the test results, that could lead to the reduction or dismissal of charges. As the cases above illustrate, successful defenses often rely on scrutinizing every aspect of the prosecution’s evidence and holding law enforcement to the highest standards.
This blog post is for informational purposes only and does not constitute legal advice. Laws regarding this may vary by jurisdiction, and the circumstances of each case are unique. If you have specific legal concerns or questions about your case, it is recommended that you consult a licensed attorney who can provide guidance tailored to your situation.
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