A proposed Illinois law would resolve some of the conflict between liberalized marijuana laws and their impact on DUI.

Under a current Illinois law, known as the “trace law,” you may be convicted of DUI if you have any unlawful substance in your system, even if your driving was not impaired. The trace law makes it easy for prosecutors since they need not prove that a drug influenced your driving. The fact a drug is in your system is enough to convict you of DUI. Because marijuana can remain in your system for up to 30 days, the trace law has led to extremely harsh penalties for actually unimpaired drivers.

If you have a lawful prescription, the prosecution must still prove you were under the influence of the drug. However, a recent Illinois Appellate court held that the push to liberalize marijuana laws did not impact the trace law. People v Rennie. Marijuana is still illegal in Illinois, the court said, and even when marijuana is legal, you are barred from driving with it in your system.

If signed by the governor, the new law would take marijuana out of the trace law. Instead, the law introduces a new standard for determining whether a driver is under the influence of marijuana. A saliva test is now available for marijuana much like the breath test for DUI. Under the new law, you could be convicted of DUI if within two hours of driving or being in actual physical control of a vehicle, you have a concentration of 15 or more nanograms of delta-9-tetrahydrocannabinol (THC) per milliliter of whole blood or 25 or more nanograms of THC per milliliter of other bodily substance.

If you are charged with DUI or similar crime, contact an experienced DUI attorney immediately. An attorney can review your case for your best possible defense. Even if the evidence against you is overwhelming, an experienced attorney who is respected in the courthouse may be able to negotiate a more favorable plea agreement than you could on your own.

Source: HB 218.
If you have questions about this or another related criminal or traffic matter, please contact Matt Keenan at 847-568-0160 or email

(Besides Skokie, Matt Keenan also serves the communities of Arlington Heights, Chicago, Deerfield, Des Plaines, Evanston, Glenview, Morton Grove, Mount Prospect, Niles, Northbrook, Park Ridge, Rolling Meadows, Wilmette and Winnetka.)

About mdkeenan

A criminal and school law attorney with over 17 years of experience, I have successfully represented clients all over the Chicago area. My practice includes DUI, felony, criminal, misdemeanor, homicide, internet crime, retail theft, traffic offenses, cyberstalking, drug crimes, weapons violations, domestic battery and juvenile crime. I also represent families involving school cases. My clients come from all over the Chicago area including Skokie, Wilmette, Niles, Northbrook, Glenview, Evanston, Winnetka, Highland park, Northfield, Park Ridge, Des Plaines and Mount Prospect. I am a member of the ACLU and the Illinois State Bar Association. I serve as a volunteer for First Defense Legal Aid. Se habla espanol.
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