How Do Cannabis DUIs Work in Illinois?

 Posted on February 18, 2025 in DUI

While cannabis is legal for adults over the age of 21 years old to possess and use in Illinois, it is not legal to drive while you are under the influence of THC. Some recent studies reported by the National Institutes of Health have found that cannabis use is not associated with an increased risk of causing a car accident. Anecdotally, you have likely heard others argue that they are, in fact, better drivers after consuming THC products. However, a large number of traffic accidents are attributed at least partially to cannabis impairment and it remains illegal to drive on a public roadway while you are under the influence. If you have been charged with a DUI because you tested positive for THC, you need a knowledgeable Arlington Heights, IL drug DUI lawyer by your side. Drug DUIs and the technology used to detect them are always changing, so it is important to have an attorney who stays up to date on DUI law and chemical testing technology.

Testing For THC Levels 

In the past, people used to be charged with DUIs if they merely tested positive for THC metabolites. This was incredibly problematic for drivers and the legal system alike. The mere presence of THC in your body does not suggest that you are actively impaired - it only indicates that you have used cannabis fairly recently. THC can remain detectable in a person’s bodily fluids for over a month after he or she stops using. As you can imagine, this led to people being arrested simply because they used cannabis days before being pulled over while perfectly sober.

The law is beginning to catch up to these realities. There is now a limit for how much THC can appear in your blood, saliva, or urine before the state will presume that you are impaired by cannabis. You can be charged with an alcohol DUI if your blood alcohol content is equal to or higher than 0.08 percent. At that level, you are presumed to be drunk. Likewise, you can be charged with a cannabis DUI if your THC levels are equal to or higher than five nanograms per milliliter of blood or 10 nanograms per milliliter of urine or saliva. At those levels, the state can presume that you consumed cannabis very recently and are presently under the influence.

THC level testing is not perfect. There is often room for an attorney to argue that an error made by law enforcement or a flawed test led to an artificially high result.

Contact an Arlington Heights, IL Defense Lawyer 

Scott F. Anderson, Attorney at Law is always up-to-date on the latest law changes regarding drug DUIs and drug DUI testing. Our experienced Cook County, IL drug DUI attorneys will develop a customized defense strategy for your case. Contact us at 847-253-3400 for a complimentary consultation.