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Will I Have To Take Field Sobriety Tests If I Am Suspected Of Being Under The Influence Of Marijuana?


If the police suspect that you are under the influence of marijuana or alcohol, they will most likely ask you to take field sobriety tests. In this context, a field sobriety test refers to a chemical test, such as a blood, breath, or urine test. Standardized field sobriety testing refers to the physical tests, the most common of which are the walk-and-turn, the one-legged stand, and the horizontal gaze nystagmus test. The physical field sobriety tests can be refused without any consequence; refusal of a chemical test, however, will result in the suspension of your driver’s license.

The physical field sobriety tests were designed to determine whether you are under the influence of alcohol—not cannabis or really any other type of drug. Until fairly recently, we were able to exclude those physical field sobriety tests from trials involving cannabis and other drugs. However, under the new medical marijuana statute, performance on the field sobriety tests can be admitted into the trial as evidence of impairment or intoxication for cannabis. This is a relatively new law, and we are still waiting to see how it will take shape and how the courts will interpret it. We are also anticipating that, since Illinois has legalized recreational marijuana use as of January 1, 2020, the field sobriety tests will be admissible in court to prove impairment of cannabis or marijuana in the absence of a medical marijuana card as well.

What If I Refused To Take The Tests?

If you refuse the physical field sobriety tests, there will be no collateral consequences with the exception of the prosecutors being able to say during trial that you refused. If you refuse the chemical field sobriety tests, then your driver’s license will be suspended.

How Will They Check For Marijuana In My System? What About Inactive THC Levels?

In order to test for cannabis in your system, they will perform a blood or urine test to determine inactive THC levels. Specifically, they will be looking for five nanograms of THC per milliliter of whole blood, or 10 nanograms of THC per milliliter of sterile blood.

What Are The Penalties For Driving Under The Influence Of Marijuana In Illinois?

In Illinois, the penalties for driving under the influence of marijuana are basically the same as the penalties for driving under the influence of alcohol. The first couple of offenses are usually misdemeanors, but as you accumulate convictions, the penalties increase and mandatory minimums can be imposed. This includes DUIs that you may have had from years ago. In Illinois, DUIs stay on your driving record for ever. This includes DUIs in which you were sentenced to Court Supervision. A first-time offense could be a felony based on having had a suspended driver’s license when you committed your first DUI, not having insurance, or causing an accident in which someone was injured or killed.

Should I Ever Admit To Officers That I Am Legally Allowed To Use Marijuana For Medicinal Purposes?

Ordinarily, I am against admitting anything to law enforcement—especially if they are questioning you in anticipation of placing you under arrest. However, I don’t see any reason to hide the fact that you are allowed to use marijuana for medicinal purposes, as they will find out about it anyway. This doesn’t necessarily mean that you should volunteer such information when being stopped for a completely unrelated matter, but if the police ask questions about your consumption of marijuana, then it would be okay to inform them that you are a medical marijuana cardholder. As far as admitting how much marijuana you have smoked or consumed, or when you smoked or consumed, that information is something that law enforcement would most likely use against you if you are arrested for DUI.

For more information on Sobriety Tests In A Marijuana Related DUI, a free initial consultation is your next best step. Get the information and legal answers you are seeking by calling (815) 290-9170 today.

Donald N. Macneil, Esq.

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