The State of Illinois decriminalized the use of medical cannabis (also known as marijuana or “pot”) on August 1st, 2013, when Governor Quinn signed the Compassionate Use of Medical Cannabis Pilot Program Act (“Medical Cannabis Act” or “Act”). The Illinois Medical Cannabis Act allows registered individuals to purchase and possess cannabis for the treatment of a “debilitating medical condition.” With the passage of the Act, certain Illinois motorists may be allowed to legally operate a motor vehicle with cannabis in their systems, provided the motorists are under a doctor’s treatment, and are not impaired.

This Act is a reversal of previous Illinois law, under which drivers were presumed to be “under the influence” if any amount of cannabis was detected in their system. But now, with the passage of the Medical Cannabis Act, drivers who have medical cannabis in their system are not breaking the law if they are capable of driving safely.

What Constitutes Impairment?

Unlike an alcohol-based DUI charge, the basis of which is a blood-alcohol concentration equal to or greater than 0.08, a cannabis-based impairment charge has no established threshold, despite the fact that the level of THC (Tetrahydrocannabinol, the ingredient in cannabis that relieves pain and makes users “high”) in the bloodstream can be measured. This leaves the determination of impairment up to the Arresting Officer. Signs of impaired driving may include, but are not limited to:

• Accelerating or decelerating rapidly
• Weaving
• Straddling a lane line
• Swerving
• Drifting
• Almost striking object or vehicle
• Stopping problems
• Varying speed
• Driving in opposing lanes
• Slow responses to traffic signals
• Driving without headlights at night
• Jerky stops and starts
• Straddling center line or land marker
• Turning with a wide radius
• Stopping without cause in traffic lane
• Failure to signal or signal inconsistent with actions

Once a Police Officer has pulled over a driver suspected of being impaired, he/she will closely observe the motorist and look for other signs of impairment, such as:

• Slurred speech
• Droopy eyelids
• The smell of burnt cannabis coming from the interior of the car, or the driver’s breath
• Difficulty understanding and responding intelligently to the Police Officer’s questions
• Fumbling with driver’s license and/or proof of insurance

Medical Marijuana (Cannabis) Registry Card & Illinois Vehicle Code

Individuals who wish to legally use cannabis for medical purposes must apply for a medical marijuana (cannabis) registry card. Pursuant to 625 ILCS 5/11-502.1 no driver, who is a medical cannabis cardholder, may use medical cannabis within the passenger area of any motor vehicle upon a highway of the State of Illinois, and may not possess medical cannabis within any area of any motor vehicle upon a highway in the State of Illinois except in a sealed, tamper-evident medical cannabis container.

Under the rules proposed by the Illinois Department of Public Health, applicants must agree not to drive while impaired and to submit to Standardized Field Sobriety Tests (SFST’s) if a Police Officer requests the driver to perform the tests. 625 ILCS 5/11-501.2(a-5) states, in pertinent part, that law enforcement officials may use standardized field sobriety tests approved by the National Highway Traffic Safety Administration (NHTSA) when conducting investigations of a violation of Section 11-501 or similar local ordinance by drivers suspected of driving under the influence of cannabis.

Although NHTSA Standardized Field Sobriety Tests were researched, designed and implemented to only detect impairment based upon a driver’s consumption of alcohol, the Illinois General Assembly has found that standardized field sobriety tests approved by the National Highway Traffic Safety Administration are divided attention tasks that are intended to determine if a person is under the influence of cannabis.

If a driver fails the Standardized Field Sobriety Tests (SFST’s), or the Police Officer has reasonable suspicion to believe that the driver may be impaired, the Police Officer may drive the suspect to a hospital for a blood and/or urine draw to test for the presence of THC (Tetrahydrocannabinol).

Test results, however, are subject to interpretation, since THC remains in the body long after the motorist has ingested cannabis and has experienced the initial high induced by the THC. A cannabis-based impairment charge, unlike an alcohol-based DUI offense, has no established quantifiable per se threshold. Some states however, such as Colorado, have established a quantifiable threshold of .05 nanograms to create per se impairment based upon the ingestion of cannabis. Complicating the determination of a cannabis-based impairment threshold is the fact that individuals react differently to the same amount of THC; while one individual may have impaired driving skills at a certain THC threshold, another driver may not.