7 Types of DUI in Illinois

DUI Based on an Alcohol Concentration of .08 or More

Under subsection (a)(1), a person may be charged when the alcohol concentration in the person’s blood, other bodily substance, or breath is .08 or more.

This is sometimes called a per se DUI, but that phrase can obscure the most important point for a client: if the State proves an admissible chemical test showing an alcohol concentration of .08 or greater, it does not also have to prove that the driver looked drunk, drove poorly, or felt intoxicated.

In other words, an (a)(1) charge generally cannot be defeated simply by arguing, “I wasn’t drunk,” “I felt fine,” or “I was driving normally.” The prohibited alcohol concentration itself is the basis of the charge.

That does not mean the chemical result is beyond challenge. Depending on the facts, the defense may examine the legality of the stop and arrest, the testing procedure, timing, equipment and records, blood collection and analysis, foundational requirements, and whether the result can be admitted and relied upon in court.

DUI Based on Being Under the Influence of Alcohol

Subsection (a)(2) creates a different type of alcohol DUI. It prohibits driving or being in actual physical control of a vehicle while under the influence of alcohol.

Unlike subsection (a)(1), the State does not need a BAC of .08 or greater to prosecute an (a)(2) DUI. A driver may provide a chemical test below .08 and still face an (a)(2) charge if the prosecution believes the other evidence proves that the driver was under the influence of alcohol.

The State may rely on evidence such as the manner of driving, physical appearance, speech, balance, field sobriety testing, statements, body-camera or squad-car video, and the observations of police officers or other witnesses.

This is why an (a)(1) case and an (a)(2) case should not be treated as the same charge. One focuses on whether the State can prove a prohibited alcohol concentration. The other focuses on whether the State can prove the driver was under the influence of alcohol.

DUI Based on an Intoxicating Compound

Subsection (a)(3) prohibits driving while under the influence of an intoxicating compound, or combination of intoxicating compounds, to a degree that renders the person incapable of driving safely.

These cases may involve substances other than alcohol or traditional controlled substances. The prosecution must connect the alleged intoxicating compound with the person’s inability to drive safely.

The particular substance, evidence of consumption, police observations, toxicology evidence, medical explanations, and circumstances surrounding the arrest can therefore become important parts of the defense analysis.

DUI Based on Drugs

Under subsection (a)(4), a person may be charged with driving under the influence of another drug or combination of drugs to a degree that renders the person incapable of safely driving.

This provision can apply even when the drug involved is a medication the person was legally entitled to use. Having a valid prescription does not by itself answer the separate question of whether the person was under the influence to the degree required by the statute.

A defense may examine the particular medication or drug, dosage and timing, toxicology results, observed behavior, medical conditions, video evidence, and whether the evidence actually establishes an inability to drive safely.

DUI Based on the Combined Influence of Alcohol and Drugs

Subsection (a)(5) prohibits driving while under the combined influence of alcohol, other drugs, or intoxicating compounds to a degree that renders the person incapable of safely driving.

These cases may involve several forms of evidence at once. A driver might have consumed alcohol but have a BAC below .08, for example, while the State also alleges that a medication or another drug contributed to the impairment.

The presence of more than one substance does not eliminate the prosecution’s obligation to prove the elements of the subsection actually charged.

DUI Based on Any Amount Resulting From Unlawful Drug Use

Subsection (a)(6) is materially different from the impairment-based provisions above. It applies when testing reveals any amount of a qualifying drug, substance, or compound resulting from unlawful use or consumption.

This provision is aimed at unlawful use or consumption of controlled substances and other substances specifically identified by Illinois law. Unlike an impairment-based drug DUI under subsection (a)(4), the State does not separately have to prove that the amount detected rendered the person incapable of safely driving.

Put more simply: an (a)(6) prosecution can be about the unlawful substance being present, rather than about how impaired the driver appeared to be.

The defense analysis may therefore focus heavily on the identity of the substance, the chemical testing, whether the detected substance resulted from unlawful use or consumption, and whether the State can establish the evidentiary foundation necessary to prove the test result.

DUI Based on THC Concentration

Subsection (a)(7) addresses tetrahydrocannabinol, or THC. It applies when a person has, within two hours of driving or being in actual physical control of a vehicle, a THC concentration meeting the statutory standard defined in Section 11-501.2.

Under the current statutory definition, that concentration is 5 nanograms or more of delta-9-THC per milliliter of whole blood or 10 nanograms or more per milliliter of another bodily substance.

Illinois law also contains a specific provision concerning lawful cannabis consumption by a qualifying patient under the Compassionate Use of Medical Cannabis Program Act who possesses a valid registry card. The application of that provision depends upon the facts of the case and the statutory requirements.