Illinois BAC Limits & DUI Consequences

0.08

Source: Illinois Rules of the Road 2026, Chapter 6: Blood-Alcohol Concentration, p. 48 · Verified Sep 2026

Illinois runs zero tolerance under age 21. Any trace of alcohol in a driver under 21 suspends driving privileges for a minimum of three months, and a Zero Tolerance Violation is defined as an alcohol concentration greater than 0.00 but less than 0.08 in a person under age 21. The under-21 threshold is therefore 0.00 rather than a measurable allowance.

Source: Illinois Rules of the Road 2026, Chapter 6: Drivers Under Age 21, p. 52 ("If you are under age 21 and found to have any trace of alcohol in your system while operating a motor vehicle, you will have your driving privileges suspended for a minimum of three months."); the 0.00 figure itself is on Chapter 8, p. 60: "Zero Tolerance Violation - Having an alcohol concentration of greater than 0.00, but less than 0.08, by a person under age 21." · Verified Sep 2026

A commercial driver is disqualified for driving a commercial motor vehicle with an alcohol concentration of 0.04 or more, half the 0.08 limit that applies to an ordinary driver, with a disqualification of at least 12 months for a first violation. A separate rule bites well below that: a commercial driver may not drive with any alcohol in their system at all, and any amount means being placed out of service for at least 24 hours. So 0.04 is where the license is lost and any measurable amount is where the trip ends.

Source: 625 ILCS 5/6-514(a)(2): disqualification for "Operating a commercial motor vehicle while the alcohol concentration of the person's blood, breath, other bodily substance, or urine is at least 0.04". 625 ILCS 5/6-515(a)-(b): no driving a commercial motor vehicle "while having any alcohol, other drug, or both in such person's system", with a mandatory out-of-service period of at least 24 hours. Illinois Rules of the Road 2026 refers commercial drivers to the separate Commercial Driver's License Study Guide (Chapter 1, p. 4) and does not print the figure. · Verified Sep 2026

Driving on Illinois roadways is consent by operation of law to chemical testing. If a police officer has probable cause to believe a driver is under the influence of alcohol, cannabis, other drugs, or intoxicating compounds, the officer will request a breath, blood, urine, or other bodily-substance test. In a personal-injury or fatal crash where probable cause exists, the officer must request a drug or alcohol test. A first refusal triggers a statutory summary suspension of one year. A driver counted as a second offender faces three years for refusing the test, or one year for failing it. Second-offender status comes from any one of four priors in the last five years: an earlier Illinois statutory summary suspension or revocation, an out-of-state suspension for refusing a test, court supervision for DUI, or a DUI conviction. An earlier refusal is only one of those four routes, so a driver whose only prior is a DUI conviction is still a second offender. Refusal can also be used as evidence in court. If the driver refuses a breath test, or the officer believes a blood test may disclose drugs, the driver may be held financially liable up to $500 for the cost of the blood tests if found guilty of DUI. After a crash with serious personal injury or death, refusing chemical testing results in a minimum one-year revocation of driving privileges.

Source: Illinois Rules of the Road 2026, Chapter 6: Implied Consent Law and Statutory Summary Suspension/Revocation Law, pp. 49-50 · Verified Sep 2026

A first DUI conviction in Illinois triggers a minimum one-year revocation of driving privileges (Chapter 6, p. 50). Separately, the statutory summary suspension imposes a six-month suspension if the driver fails chemical testing (BAC of .08 or more) or a one-year suspension if the driver refuses chemical testing; the suspension begins on the 46th day after the officer's notice. A BAC of .16 or more, or a DUI while transporting a child under age 16, triggers enhanced penalties. Before reinstatement, the driver must complete an alcohol and drug evaluation, complete a rehabilitation or alcohol/drug education program, attend an administrative hearing with the Secretary of State, pay a reinstatement fee, and file SR-22 financial responsibility insurance for three years. A first-time offender may petition for a Monitoring Device Driving Permit (MDDP), which requires installation of a Breath Alcohol Ignition Interlock Device (BAIID) on the offender's vehicle at the offender's expense; choosing not to participate and driving anyway during the suspension is a felony. The handbook narrates these outcomes but does not state the specific fine amount or jail term; 625 ILCS 5/11-501(c)(1) makes a first DUI a Class A misdemeanor, and the Class A misdemeanor range at 730 ILCS 5/5-4.5-55 is a jail term of less than one year, with a fine of up to $2,500. One carve-out matters more than any other for a reader using this book, because most of them are the ones it applies to: a driver under 21 convicted of a first DUI faces a revocation of at least two years, not one. The under-21 track also runs below the adult threshold. Any trace of alcohol in the system while driving suspends the license for at least three months, with no DUI charge required, and a conviction or court supervision for illegal consumption, purchase, possession, or receiving alcohol as a gift costs driving privileges too, whether or not a vehicle was involved.

Source: Illinois Rules of the Road 2026, Chapter 6: DUI Laws, Statutory Summary Suspension/Revocation Law, and DUI Conviction, pp. 49-50; offense class per 625 ILCS 5/11-501(c)(1) ("any person convicted of violating subsection (a) of this Section is guilty of a Class A misdemeanor") and sentencing range per 730 ILCS 5/5-4.5-55. Illinois Rules of the Road 2026, Chapter 6: Drivers Under Age 21, p. 52: "If you are under age 21 and convicted of DUI, you face the revocation of your driving privileges for a minimum of two years for a first conviction" and "If you are under age 21 and found to have any trace of alcohol in your system while operating a motor vehicle, you will have your driving privileges suspended for a minimum of three months." · Verified Sep 2026

conditional

Source: Illinois Rules of the Road 2026, Chapter 6: Breath Alcohol Ignition Interlock Device (BAIID), p. 50 · Verified Sep 2026