The Best Defense for a DUID Charge

First things first, you have to understand that the charges against you do not so much concern the levels of THC found in your blood, but rather how impaired you were while driving. Your mentality should be to prove that you were not impaired, instead of trying to prove that you hadn’t consumed marijuana within the last few days.

In order to defend yourself against a DWAI/DUID charge, you’ll have to first understand the laws and sciences behind your charges. According to Colorado House Bill 1325, which was passed back in 2013, the legal definition of impairment for marijuana is set to five nanograms of active delta 9-tetrahydrocannabinol (THC) per milliliter of blood.

So the question remains, how much is that exactly? The simple answer – no one knows. The hardest aspect of Marijuana DWAI cases for the prosecutors is the fact that it’s extremely difficult to prove impairment solely through test results. In fact, blood test results never prove impairment, but instead merely show marijuana’s presence in the body, which again is not always directly correlated to impairment. There are hundreds of contradicting studies that try to peg a number on impairment, but thus far there has been very little consensus in the scientific community.

Marijuana transfers rapidly through the bloodstream, typically reaching peak concentrations of more than 100 nanograms per milliliter of blood (ng/mL) within the first five to ten minutes. THC concentration then rapidly decreases to between one and four ng/mL within the first three to four hours in a typical occasional smoker. However, habitual marijuana users have been found to test positive for active levels of THC for as long as a full week after abstention (with the highest concentration detected being three ng/mL in the study). Therefore, if you are a medical marijuana patient who takes their medicine daily, your active THC levels will have a much longer life expectancy than the occasional smoker. Further, the amount of traceable THC that remains in someone’s blood (and for how long) greatly varies person to person. Depending on your percentage of body fat, frequency of use, and even age, your results may differ immensely from someone who’s ingested the same amount of marijuana.

How can you prove your innocence?

Knowing that a person can test positive for impairment due to THC as long as days after ingesting marijuana, you should build your defense on proving that you were not “impaired.” According to the National Highway Traffic Safety Administration, “Marijuana has been shown to impair performance on driving simulator tasks and on open and closed driving courses for up to approximately 3 hours.” Thus, as long as you can prove that you hadn’t smoked 5 hours previously to getting pulled over, you can cite the National Highway Traffic Safety Administration as a source. Jurors are inherently sympathetic to drivers who, through no fault of their own, are cursed with debilitating illnesses and who are required to take medicines in order to live partially normal lives. So although being a medical marijuana patient does not allow you to drive after smoking, showing that you’re being medicated daily may convince the jury that the blood test results should be deemed invalid.


Be sure to read our DUID (Marijuana) In Colorado FAQ article.

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Revised: May 16, 2022, 6:22 a.m.
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