Illinois residents may be aware that several states recently legalized the recreational use of marijuana. As restrictions on marijuana use loosen around the country, there are growing concerns about how to prevent motor vehicle accidents by drivers that may be impaired by marijuana. As of yet, there is no reliable testing method for marijuana impairment that can be used during traffic stops.

A study by the Automobile Association of America found that marijuana affects people differently, so there is no way to scientifically measure a driver’s level of marijuana intoxication. Another problem with roadside testing for marijuana intoxication is that THC can still be detected in a person’s blood or urine for weeks after the person last smoked pot.

Despite the problems with marijuana testing, there are many companies looking to cash in on marijuana field tests. Several companies have obtained patents for marijuana testing devices including marijuana breath tests. Even if a company develops technology that can quickly and reliably detect a driver’s THC level, it is unclear what THC level will be considered unsafe for drivers. The AAA report said that legal limits for marijuana impairment should be abandoned in favor of behavioral and physiological measurements of impairment.

Because THC stays in the body for weeks, a driver could be charged for driving under the influence of marijuana even if they have not consumed any marijuana for weeks. A person who has been handed a marijuana-related DUI charge may want to work with a criminal defense attorney to dispute their charge. An attorney may help the defendant to prove that they were not intoxicated at the time of the traffic stop.