The Illinois legal BAC limit for a standard non-commercial driver over age 21 is 0.08 under 625 ILCS 5/11-501(a)(1). At 0.08 or above, the state can secure a DUI conviction based on the number alone, without proving actual impairment. Commercial drivers face a lower limit of 0.04 under 625 ILCS 5/6-515. Drivers under 21 are subject to zero tolerance under 625 ILCS 5/11-501.8, meaning any measurable alcohol (0.00 to 0.08) triggers license suspension even without a DUI conviction. Illinois also has a high-BAC enhancement at 0.16 or above, which adds mandatory minimum jail or community service to a first-offense conviction. Refusal to submit to testing triggers a separate 12-month suspension.
