Illinois amends DUI law to set a “legal limit” for Marijuana DUIs

Governor Rauner has signed SB 2228, which, among other things, amends the DUI statute, removing the provision that made it a DUI if a person drives or is in actual physical control with any amount of cannabis in his or her blood, breath or urine (i.e., a “zero tolerance” law), and adding a new section of the DUI law which makes it a violation to drive or be in actual physical control of a motor vehicle with more than 5 ng of THC per ml of whole blood or 10 ng of THC per ml of any other bodily substance.

While this law is not perfect (a recent federal study found that 13 ng of THC is the closest equivalent to the 0.08 blood alcohol limit in terms of causing impairment), it is a major improvement from the zero tolerance standard, which made it illegal to drive so long as any THC remained in a person’s system, regardless of impairment.  Theoretically, under the old law, a person could be charged with DUI a month after using marijuana.

(The new law does not change the pre-existing law in Illinois which makes it a DUI to drive while under the influence of cannabis.  At trial, this would have to be proved by the arresting officer’s expert testimony that the person was impaired due to consumption of cannabis.  Like a DUI for alcohol, a person can be found guilty even if he or she is under the “legal limit” if the court finds that he or she was impaired to the point that he or she was unable to safely operate a motor vehicle).

The law also decriminalized possession of marijuana and marijuana paraphernalia.  Possession of less than 10 grams of marijuana is now a fine-only civil offense, and there will be automatic expungement of these citations.