IL HB4890

Amends Illinois Vehicle Code Section 11-501 to prohibit driving with tetrahydrocannabinol (THC) concentration in breath, blood, or other bodily substance (excluding urine) within 2 hours of driving, rather than limiting the prohibition to whole blood or bodily substance as previously defined.

Excludes lawful cannabis consumption by licensed medical cannabis patients with valid registry cards from the THC driving prohibition, unless the person is impaired by cannabis use.

Modifies Section 11-501.2 to define "delta-9-tetrahydrocannabinol" for trial purposes to include parent delta-9-tetrahydrocannabinol or free delta-9-tetrahydrocannabinol, and establishes THC concentration thresholds of 5 nanograms per milliliter in whole blood or 10 nanograms per milliliter in other bodily substance.

Authorizes law enforcement to use validated roadside chemical tests and standardized field sobriety tests approved by the National Highway Traffic Safety Administration for cannabis-related driving investigations, with results admissible in civil and criminal proceedings.

Maintains existing criminal penalties for DUI violations, including Class A misdemeanor for first offense, mandatory minimums for repeat offenses, and felony charges for aggravated violations involving injuries, deaths, or multiple prior convictions.