The Science Behind Marijuana DUIs
High THC Levels Don't Always Mean Impairment:
In Arizona, DUI cases involving Marijuana are becoming more common as Cannabis use increases. However, these cases are not as straightforward as those involving alcohol. THC, the psychoactive compound in Marijuana, behaves very differently in the body than alcohol, and its effects on impairment are much harder to measure. In this post, we’ll explore what THC levels in the blood really mean, why they don’t always equate to impairment, and how these complexities can impact marijuana DUI cases. If you’re facing a Marijuana DUI in Tucson, Arizona, Amanda Bynum at AJB Law Firm, LLC is here to help.
What Do THC Levels in the Blood Really Mean?
When it comes to THC (Tetrahydrocannabinol) in the bloodstream, many people assume that a high concentration directly correlates with impairment. But the science behind THC levels tells a different, much more nuanced story. Unlike alcohol, which has a well-established relationship between blood alcohol concentration (BAC) and impairment, THC behaves unpredictably in the body, making it difficult to draw definitive conclusions about a person’s level of impairment based on a single blood test.
THC levels are typically measured in nanograms per milliliter (ng/mL). You may hear figures like 2 ng/mL, 5 ng/mL, or even higher levels cited in discussions of impairment, but these numbers do not carry the same weight as a BAC measurement. For instance, while a BAC of 0.08% is widely accepted as the threshold for legal impairment, there is no universally agreed-upon THC level that signifies a person is too impaired to drive. This ambiguity creates significant challenges in marijuana DUI cases, where law enforcement often relies on blood test results to support their claims of impairment.
As an example, a concentration of 65 ng/mL of THC is undeniably high and typically reflects recent, heavy marijuana use. This level might occur shortly after consuming a potent form of marijuana, such as through vaping, dabbing, or consuming high-dose edibles. However, the key issue is that THC levels in the blood rise and fall rapidly. After inhaling marijuana, THC levels can spike to 100 ng/mL or more within minutes but may decline sharply within an hour or two. This means that by the time someone is pulled over, subjected to a blood test, and results are obtained, the measured THC level might not accurately reflect their condition when they were actually driving.
Moreover, individual differences in THC metabolism complicate the interpretation of these results. Factors like tolerance, frequency of use, body fat percentage, and metabolism play a major role in how long THC remains detectable and how it affects a person. Chronic users—those who use Marijuana regularly—can often have consistently high THC levels in their blood long after the psychoactive effects have worn off. For these individuals, a reading of 65 ng/mL might not indicate any functional impairment, as their bodies have adapted to the presence of THC. Conversely, an occasional user might experience significant impairment with a much lower THC concentration.
This discrepancy underscores why blood THC levels alone are insufficient to prove impairment. A forensic toxicologist can testify in DUI cases that while a high THC level might suggest recent use, it cannot definitively establish that a person was impaired at the time they were driving. Behavioral evidence, such as performance on field sobriety tests or erratic driving behavior, is far more indicative of impairment than a single blood test result. Additionally, field sobriety tests themselves are problematic when it comes to detecting marijuana impairment, as they were developed to identify alcohol-related impairment and lack scientific validation or correlation to marijuana use.
For law enforcement and prosecutors, these challenges mean that proving impairment to the slightest degree due to Marijuana requires more than just a number on a toxicology report. For defense attorneys, this opens avenues to challenge the prosecution's case by questioning the reliability of THC tests to prove impairment, the timing of blood draws, and the subjective nature of impairment assessments. If you’re navigating a marijuana DUI case, Tucson DUI attorney Amanda Bynum can guide you through this complex process.
Why THC Levels Don't Prove Impairment
Unlike alcohol, where blood alcohol concentration (BAC) has a clear correlation with impairment, THC doesn't work the same way. THC’s effects depend on many factors, including how it is consumed, the user’s tolerance, and their unique body chemistry. Two people could have identical THC levels but vastly different levels of impairment—or no impairment at all. This lack of consistency creates challenges for prosecutors who try to argue that a specific THC level is evidence of a defendant’s inability to safely operate a vehicle.
Additionally, THC’s psychoactive effects peak quickly and diminish rapidly, while blood levels might remain elevated long after the effects have subsided. This disconnect is why a person might register a high THC concentration in their blood without exhibiting any signs of impairment. It’s also why many legal and scientific experts argue that behavioral evidence, such as driving patterns or physical coordination, should weigh more heavily in DUI cases than blood THC levels alone.
To add another layer of complexity, the method of Marijuana consumption can significantly affect how THC is processed by the body. Smoking or vaping leads to an immediate spike in THC levels, while edibles take longer to metabolize but can result in prolonged psychoactive effects. This variability further complicates the ability of law enforcement to make accurate assessments of impairment based solely on THC blood concentrations.
For individuals accused of a Marijuana DUI in Arizona, these scientific uncertainties can play a critical role in building a defense. Amanda Bynum at AJB Law Firm, LLC, specializes in challenging DUI charges by leveraging the latest research and expert testimony to question the reliability of the evidence presented.
The Role of Behavioral Evidence
While THC blood levels are often cited in Marijuana DUI cases, behavioral evidence remains a crucial component in proving impairment. Law enforcement officers typically rely on field sobriety tests (FSTs) to evaluate a driver’s physical coordination and mental acuity. However, these tests were designed to detect alcohol-related impairment and have not been scientifically validated for marijuana use.
Field sobriety tests often include tasks such as walking in a straight line, standing on one leg, or following a moving object with your eyes. These tests assume that any failure indicates impairment, but other factors, such as nervousness, medical conditions, or even uneven terrain, can affect performance. For Marijuana DUIs, the subjective nature of these tests is a significant weakness in the prosecution’s case.
Forensic toxicologists often emphasize that behavioral observations should be assessed alongside scientific evidence, not in isolation. For instance, a driver who demonstrates clear decision-making and motor skills despite a high THC blood level might not be impaired. Conversely, a low THC level paired with erratic driving behavior could suggest some level of impairment. This nuanced approach is why it’s essential to have a defense attorney who understands both the science and the law. Tucson DUI attorney Amanda Bynum knows how to dissect these complexities to build a strong defense for her clients.
How a DUI Attorney Can Help
Facing a Marijuana DUI charge can be overwhelming, but having an experienced defense attorney can make all the difference. At AJB Law Firm, LLC, Amanda Bynum has years of experience handling DUI cases in Tucson and understands the intricacies of Arizona’s Marijuana and DUI laws. Here are some of the ways she can help:
Scrutinizing THC Test Results: Amanda will examine the timing, accuracy, and methodology of the blood test used in your case. This includes questioning whether the sample was properly handled and whether the results truly reflect impairment.
Challenging Field Sobriety Tests: Many FSTs are unreliable for detecting Marijuana impairment. Amanda will highlight the lack of scientific validation for these tests in your case.
Leveraging Expert Testimony: By working with forensic toxicologists and other experts, Amanda can provide evidence that challenges the prosecution’s interpretation of THC levels.
Presenting Behavioral Evidence: Amanda will use witness testimony, dashcam footage, and other evidence to show that you were not impaired at the time of the alleged offense.
Arizona’s Marijuana DUI laws are strict, but they’re also rooted in outdated assumptions about impairment. Amanda Bynum stays up-to-date on the latest research and legal strategies to give her clients the best possible defense.
Conclusion
Marijuana DUI cases are complex, and the science doesn’t always support the State’s claims. If you’re facing a marijuana DUI in Tucson, Arizona, it’s crucial to have an attorney who understands both the science and the law. Amanda Bynum at AJB Law Firm, LLC has the experience and expertise to challenge the evidence against you and fight for your rights. Contact us today to schedule a consultation and learn how we can help you navigate the legal system and achieve the best possible outcome.
If you’re searching for a trusted Tucson DUI attorney with a proven track record, Amanda Bynum at AJB Law Firm, LLC is here to help. Call us today to discuss your case.
