Cannabis DUI Charge in Will County
In Illinois you can be charged with DUI if a test finds 5 nanograms or more of THC per milliliter of whole blood, or 10 nanograms or more in another bodily substance, within 2 hours of driving. Impairment is a separate way to be charged, and it does not need a number.
Your deadlines
- Day 46. Your statutory summary suspension starts, counted from the day you got the notice.
- Day 90. The last day to file a petition to rescind that suspension.
What happens next
- An officer stops you and says they smell cannabis or see signs of impairment.
- You may be asked to do field sobriety tests and to give a blood or other sample.
- If you are arrested, you get a notice of suspension and a court date at the Will County Courthouse in Joliet.
- The suspension starts on the 46th day after the notice. Asking for a hearing does not delay it. Only a judge's order rescinding it stops it.
- Your case moves through arraignment, discovery and then a plea, a trial or another resolution.
The THC limit in the statute
Section 11-501(a)(7) of the Vehicle Code makes it a DUI to have a set THC concentration within 2 hours of driving or being in actual physical control of a vehicle. Section 11-501.2 sets the numbers.
| Sample type | THC level that counts |
|---|---|
| Whole blood | 5 nanograms or more per milliliter |
| Other bodily substance | 10 nanograms or more per milliliter |
The 2 hour window matters. The statute counts it from the time you were driving or in control of the vehicle, so the timing of the sample is part of the case.
The presumption and what it leaves open
At trial, a result of 5 or 10 nanograms or more raises a presumption that you were under the influence of cannabis. A presumption can be answered with other evidence.
A result under those levels does not create a presumption either way. The court may still weigh it with other evidence on whether you were impaired. So a low number does not end a case, and a high number does not end one either.
Arrested for DUI? Call Jeff now.
The license clock starts the day you get the notice. During office hours, Jeff answers the phone himself.Office hours: Monday to Friday 8:30 AM to 6 PM, Saturday 10 AM to noon. After hours, leave your name, number and the best time to call back.
Jeff McCarthy, Inspired Law Group, 136 E 9th St, Lockport, IL 60441
The medical cannabis exception
The (a)(7) THC rule does not apply to lawful use by a qualifying patient who holds a valid registry card under the Compassionate Use of Medical Cannabis Program Act. There is a catch. The exception stops working if you are impaired by the cannabis. The law also says that being legally allowed to use cannabis is not a defense to a DUI charge by itself.
If you have a card, bring it to your first meeting with Jeff.
Penalties and license effects
A first cannabis DUI under subsection (a) is a Class A misdemeanor. The Secretary of State must revoke the license of a person convicted of DUI. Other consequences can start before the case ends.
- A test at or above those THC levels brings a 6 month statutory summary suspension for a first offender. Refusing a test brings 12 months.
- An officer who has reasonable suspicion of cannabis impairment can ask for field sobriety tests. Refusing them, failing to finish them, or failing them brings a field sobriety suspension on the 46th day. A court hearing request does not stop it from starting.
- A court can order an alcohol and drug evaluation and a victim impact panel.
Questions Jeff asks first
- When did you last use cannabis, and in what form?
- When were you stopped, and when was the sample taken?
- Were you asked to do field sobriety tests, and did you finish them?
- Do you hold a medical cannabis registry card?
The answers decide which parts of the statute apply and which dates matter. Tell Jeff the full story, including the parts that seem to hurt.
How Jeff defends this charge
- He checks the timeline. If the sample was taken long after the stop, he asks how the state ties the number to the 2 hours.
- He looks at what kind of sample it was, because the 5 and 10 nanogram levels depend on whole blood or another substance.
- He reviews who drew the blood and how the lab handled it, using the rules in section 11-501.2.
- He asks whether the officer had a legal reason for the stop and for the field tests.
- He checks whether a medical cannabis card changes the charge.
- He reviews the smell and observation notes, since an odor alone does not measure impairment.
Each case turns on its own facts, and none of these points predicts a result.
Sources
Reviewed by Jeff McCarthy, Attorney, Inspired Law Group, 136 E 9th St, Lockport, IL 60441.
Questions people ask about cannabis dui
Short answers first. Jeff McCarthy reviews every answer on this page.
The DUI law uses 5 nanograms of THC per milliliter of whole blood, or 10 nanograms per milliliter of another bodily substance, tested within 2 hours of driving.
The THC concentration rule in (a)(7) looks at the number in a test taken within 2 hours. A person can also be charged for being impaired. A medical card holder is treated differently unless impaired.
It protects against the THC number rule only. If the state says the cannabis impaired you, the charge can still go forward. Being allowed to use cannabis is not a defense by itself.
The statute does not say how long THC stays in the body. It looks at the concentration within 2 hours of driving. Jeff reviews the timing of your test against that window.
You can refuse, but refusing brings a field sobriety suspension on the 46th day. The suspension is automatic and a hearing request does not pause it.
A first DUI under subsection (a) is a Class A misdemeanor. It can become a felony in cases like a crash with great bodily harm or a third offense.
Keep reading
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Every case comes down to its facts and its deadlines. Talk with Jeff McCarthy so you can:
- Get clear on your legal options.
- Avoid costly mistakes.
- Know what happens next, and when.

