IL HB4590

Adds prohibition against driving or being in actual physical control of a vehicle while under the influence of cannabis as a new violation under Illinois Vehicle Code Section 11-501.

Establishes that a person violates the law if they have any tetrahydrocannabinol (THC) concentration in whole blood or bodily substance within 2 hours of driving, with exception for medical cannabis patients with valid registry cards unless impaired.

First violation of driving under cannabis influence is a Class A misdemeanor; second violation carries mandatory minimum of 5 days imprisonment or 240 hours community service.

Exempts qualified medical cannabis patients licensed under the Compassionate Use of Medical Cannabis Program Act from THC concentration violation if they possess valid registry card and are not impaired.

Establishes that legal entitlement to use cannabis does not constitute a defense to charges of impaired driving.