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Saliva Testing the Latest Tool in DUI Enforcement

Posted on in DUI Defense

Illinois DUI defense lawyerBreath testing for blood-alcohol content (BAC) has been the gold standard in DUI law enforcement for decades. However, with marijuana use on the rise, as well as concerns about opioid use, there is a clear need for faster and more accurate methods of testing for drug-impaired driving.

Illinois Law on Drug-Impaired Driving

Illinois law defines the offense of “driving under the influence” in seven distinct ways, using both subjective and numeric measures. In the broadest terms, it is illegal to drive under the influence of any combination of intoxicating compounds, alcohol, or other drugs “to a degree that renders the person incapable of safely driving.”

In addition to that subjective standard, Illinois also has established several measurable standards to facilitate enforcement of the law (625 ILCS 5/11-501).

DUI-marijuana: A person must not drive when they have, within 2 hours of driving, a THC concentration of either 5 nanograms or more per milliliter of whole blood or 10 nanograms or more per milliliter of other bodily substance. THC is the psychoactive chemical found in marijuana.

DUI-other drugs: A person must not drive with “any amount” in the person’s breath, blood, urine, or other bodily substance of a controlled substance listed in the Illinois Controlled Substances Act, an intoxicating compound listed in the Use of Intoxicating Compounds Act, or methamphetamine as listed in the Methamphetamine Control and Community Protection Act.

Saliva Tests May Be the New Standard for Marijuana DUI

To determine if someone is too high on marijuana to drive safely, the current method is a blood test. This is not ideal, however, because there is a relatively weak correlation between the level of THC in the blood and the degree of physical and mental impairment. THC remains active in the brain for several hours, so a driver can remain impaired even after their blood-THC drops below the legal level.

Since THC is not a water-soluble substance, marijuana use can be detected in saliva either as residual smoke or the “parent drug” within minutes of use and for no more than 24 hours after. This provides a better correlation between the test results and the ability to drive safely.

In contrast, it can take as long as 24 hours for the body to metabolize marijuana and THC to the point where the metabolites (e.g., THC-COOH) can be detected in a urine sample and then can remain detectable for several days in regular users, long after the psychoactive effect has worn off. In other words, someone could test over the legal limit for THC in their blood or urine, but their ability to drive safely would not be affected.

For police officers, saliva swabs offer a faster, easier, and less invasive method of collecting a testable sample for DUI enforcement. Saliva tests can produce results within 10 minutes, detecting a range of substances including alcohol, cocaine, marijuana, meth, and opiates. In contrast, blood or urine testing requires taking suspects to a central collection site such as a medical center and waiting sometimes days for test results to come back.

Consult a Knowledgeable Oak Brook DUI Defense Lawyer

If you have been arrested for DUI and tested over the Illinois legal limit for THC due to marijuana use, do not give up or give in. Call a knowledgeable DuPage County DUI defense attorney to discuss your options. There are many ways we can help you get a better outcome to your case through investigation, negotiation, and litigation. Call McMahon Law Offices at 630-953-4400. We offer free consultations as well as weekend and evening hours.






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