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Marijuana DUI Laws: Debunking the Science Behind Blood Tests

Would you believe it if the nation’s largest auto club claimed that marijuana DUI laws are scientifically baseless and largely nonsensical? According to AAA and many other groups and prominent figures, the standards used by states to determine impairment related to marijuana have no real connection to a person’s actual impairment status. In other words, a blood test for marijuana cannot definitively determine whether someone is currently high.

The intention behind these state laws is clear – to ensure that impaired drivers, whether due to alcohol or drugs, are kept off the road for the safety of all. By penalizing individuals who operate vehicles with a certain amount of a substance in their system, these laws aim to serve as a deterrent for potential offenders. However, the real issue lies in the seemingly arbitrary numbers set by states to determine impairment.

For instance, let’s consider Colorado, a state with legal marijuana. Colorado has established that driving with five nanograms of THC (the psychoactive compound in marijuana) per milliliter of blood constitutes impairment. This threshold has faced significant criticism and scrutiny.

Firstly, THC tends to linger in the body for an extended period, especially when compared to other substances like alcohol, prescription drugs, or harder illicit drugs such as cocaine. THC can remain detectable in the body for weeks, particularly among chronic users. Furthermore, individuals who use marijuana for medicinal purposes to manage chronic pain may have high levels of THC in their bloodstream without experiencing impairment.

The five-nanogram limit appears to lack a solid scientific foundation and seems to have been arbitrarily chosen by lawmakers. Consequently, many innocent individuals find themselves facing DUI-D (Driving Under the Influence of Drugs) charges despite not being genuinely impaired.

Fortunately, DUI-D cases often provide a solid basis for legal defense, and many of these cases ultimately result in dismissal. The controversy surrounding the science behind marijuana DUI laws has prompted legal challenges and calls for more accurate impairment detection methods.


In conclusion, the debate over marijuana DUI laws continues to highlight the complexities surrounding the regulation of marijuana and impaired driving. While states aim to ensure road safety, these laws’ effectiveness and fairness remain subject to debate. For individuals facing DUI-D charges in Colorado, seeking legal representation from experienced professionals like Thomas & Ahnell, LLC can be essential in navigating the legal system and protecting their rights.

Do you have further questions or concerns? Call us or contact the attorneys at Thomas & Ahnell, LLC, and we will be happy to help.

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