Driving Under the Influence (DUI)

“Driving Under the Influence” is defined as operating a motor vehicle while impaired by alcohol, other drugs, including cannabis (marijuana) prescribed for medical purposes, or intoxicating compounds and methamphetamine. In Illinois, you are legally considered to be under the influence if you: (1) have a blood-alcohol con-tent (BAC) of .08% or more; (2) have a tetrahydrocannabinol (cannabis) concentration (THC) of either 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substance; (3) have used any other controlled substance; or (4) are impaired by medication.  

Blood-Alcohol Content (BAC)

BAC is a measurement of the amount of alcohol in your system based on a test of your breath, blood or urine. It is illegal to drive if your BAC is .08% or more. However, you can be convicted of a DUI if your BAC is less than .08% and your driving ability is impaired.  Your BAC is determined primarily by two fac-tors: how much alcohol you drink and how much time passes between drinks. Other con-tributing factors include gender, body weight, alcohol tolerance, mood, environment and the amount of food consumed. 

From your first drink, alcohol affects your coordination and judgment. Even with a BAC well below .08%, your reaction time slows. Your risk of being in a crash begins to climb with a BAC between .04% and .05% and increases rapidly after that. By the time you reach a BAC of .06%, you are twice as likely to be involved in a fatal crash as a non-drinking driver. By the time you reach a BAC of .08%, you are 11 times more likely to be killed in a single-vehicle crash than a non-drinking driver.  The only way to rid the body of alcohol is time. Fresh air, coffee, a shower and food cannot change your BAC or make you sober. It takes about one hour for the body to metabolize one drink. Each of the following has a comparable amount of alcohol and counts as one drink: one 12-ounce mug of beer, one 5-ounce glass of wine or one 1.5-ounce shot of hard liquor. (The amount of alcohol in a poured/mixed drink is dependent on the type of drink and the person who pours it.) 

Medical and Recreational Cannabis (Marijuana) 

Illinois law allows for the medical and recreational use of cannabis if you are age 21 or older. Individuals who wish to use cannabis for medicinal purposes may enroll in the Compassionate Use of Medical Cannabis Program, administered by the Illinois Department of Public Health. The Department of Public Health will issue a registry ID card, and a notation will be made on the registrant’s Illinois driving record.  

It is illegal to operate a motor vehicle while impaired by the use of cannabis, whether used medically or recreationally. If you are carrying cannabis in your vehicle, the container must be sealed, odor-proof and child resistant. No driver or passenger may use cannabis in a motor vehicle. Suppose a law enforcement officer stops your vehicle and has reasonable suspicion to believe you are impaired by the use of cannabis. In that case, you must submit to field sobriety testing and/or validated roadside chemical tests. Refusal to submit to testing or failure of field sobriety tests and/or validated roadside chemical tests will result in the suspension of your driver’s license.  

Driving while impaired by the use of cannabis or illegal transportation of cannabis in a motor vehicle may result in the loss of your driving privileges and the revocation of your medical cannabis card, if applicable. 

The DUI Arrest

  • An officer stops a vehicle at a roadside safety check or for probable cause, reasonable suspicion or unusual operation.
  • The officer observes the driver and requests a driver’s license, vehicle registration and proof of insurance.
  • If the officer suspects the driver is under the influence, the driver is asked to submit to field sobriety tests.
  • If the officer does not suspect the driver is under the influence, the driver is released without any applicable violations.
  • If the officer has probable cause based on the field sobriety tests, the driver is placed under arrest for DUI and taken to the police station. The driver is asked to submit to chemical testing of breath, blood, urine or other bodily substances.
  • If a tested driver has a BAC of more than .05% but less than .08%, a THC of less than either 5 nanograms or more per milliliter of whole blood or 10 nano grams or more per milliliter of other bodily substance, and no drugs found in their  system, no statutory summary suspension will apply; however, the associated DUI charge will remain until appropriate action is taken by the court.
  • If the driver refuses to submit to or fails to complete chemical testing, a statutory summary suspension will be imposed. If the driver is a first-time DUI offender, they may be eligible for a Monitoring Device Driving Permit. If the driver is a repeat DUI offender, they may be eligible for a Restricted Driving Permit (RDP).
  • If the driver’s test results show a BAC of .08% or more, a THC of either 5 nano -grams or more per milliliter of whole blood or 10 nanograms or more per milli-liter of other bodily substance, or any trace of a drug  (other than cannabis), illegal substance or intoxicating compound, the driver will be issued a law  enforcement sworn report notifying the driver of a statutory summary suspension.
  • If the driver’s license is valid, a receipt is issued allowing driving for 45 days.
  • A driver may obtain additional testing at their own expense; the results are admissible in court.
  • The offender is required to post bond and may be detained until bond is posted.
  • The offender’s vehicle may be towed, impounded or seized.

Statutory Summary Suspension of Your Driver's License

A statutory summary suspension is the automatic suspension of your driving privi-leges resulting in a DUI arrest for failing, refusing to submit to, or failing to complete chemical testing. Failure of chemical testing means you have a BAC of .08% or more, a THC of either 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substance, or a trace of other drugs. Statutory summary suspensions are automatic and effective on the 46th day from the date of your suspension notice. This suspension does not replace criminal penalties for a DUI conviction. You may request a judicial hearing to challenge the arrest; however, the request does not stop your suspension from taking effect.   

If you refuse to submit to chemical testing in another state, your  driving privileges will be suspended. A statutory summary suspension does not apply if your BAC is less than .08%. A statutory summary suspension does not apply if you have a THC of less than either 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substance  unless you are a CDL holder. If your BAC is more than .05% and additional evidence such as an open container warrants a DUI arrest, the outcome of the court case will determine if penalties apply. If you are a commercial driver’s license holder and receive a statutory summary suspension, your CDL privileges will be disqualified for one year for a first offense; a lifetime disqualification applies for a second offense.  

Suppose you are convicted of DUI and your driving privileges were suspended because of a statutory summary suspension. In that case, you will have that time credited to the minimum period of revocation of driving privileges. The DUI criminal charge is prosecuted and  adjudicated in the courts. This charge is separate from the statutory summary suspension penalties, which is the administrative process. For more information on the criminal penalties for a DUI conviction.  

A law enforcement officer is required to request a chemical test when there is probable cause to suspect DUI is a factor when a crash results in personal injury or death. If you refuse to submit to such testing, your driving privileges will be revoked for a minimum of one year.  

If you are subject to chemical testing, you may be liable for the medical costs associated with the blood test (up to $500) if you are consequently convicted of DUI.  

Your driver’s license may be subject to multiple suspensions or revocations simultaneously. No single suspension or revocation serves to negate, invalidate, cancel, postpone or lessen the effect of any other suspension or revocation.

Failed Chemical Testing

  • First offense — Suspension of driving privileges for six months (eligible for a Monitoring Device Driving Permit).
  • Second or subsequent offense within five years — Suspension of driving privileges for one year.

Refusing to Submit to Chemical Testing

  • First offense — Suspension of driving privileges for 12 months (eligible for a Monitoring Device Driving Permit).
  • Second or subsequent offense within five years — Suspension of driving privileges for three years.

*A DUI offender eligible for driving relief and issued a Monitoring Device Driving Permit (MDDP) must operate only vehicles installed with a Breath Alcohol Ignition Interlock Device (BAIID) unless exempted by employment. The offender is subject to all MDDP rules and BAIID fees.

Contest Your Driver's License Suspension 

You may request a judicial hearing to challenge a statutory summary suspension or statutory summary revocation within 90 days after the notice date. The hearing must be conducted within 30 days of the request or on the first court date to consider the criminal charges. 

Legally, only certain issues may be considered: 

  • Whether you were arrested for DUI.
  • Whether there were reasonable grounds to believe that you were driving at the time of arrest or in physical control of the vehicle while under the influence of alcohol or other drugs.
  • Whether you, after being informed of the impending summary suspension, refused to submit to chemical testing.
  • Whether, after being advised of the suspension, you submitted to chemical test-ing that showed a BAC of .08% or more; a THC of either 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substance; or any trace of a controlled substance, methamphetamine and/or intoxicating compounds.
  • Whether, in the case of a statutory summary revocation, you were involved in a motor vehicle crash that caused personal injury or death.
  • Whether the officer had reasonable suspicion to believe that you were driving or in actual physical control of a motor vehicle while impaired by the use of cannabis.