According to data from the National Highway Traffic Safety Administration, an increasing number of drivers in Illinois and across the U.S. are being to have marijuana in their systems. As more states legalize medical and recreational use of marijuana, researchers are trying to establish a THC threshold test similar to the blood alcohol level tests used for drunk drivers.
To that end, in June, the National Institute on Drug Abuse released a study examining the effect THC has on driving performance. Researchers had 18 occasional marijuana users, who ranged between the ages of 21 and 37, take six simulated driving tests after consuming different amounts and combinations of THC, alcohol and placebos. Researchers particularly scrutinized the number of times the car left the lane, weaving within the lane and the speed of any weaving. They found that, unlike alcohol, marijuana did not effect the number of times the car veered from the lane. However, drivers who had THC blood concentrations of 13.1 ug/L weaved their cars in manner similar to drivers with a .08 blood alcohol level. In Washington and Colorado, 5 ug/L is the legal THC limit for drivers, and .08 is the legal alcohol limit for drivers in all 50 states.
The researchers also noted that consuming alcohol with marijuana increased the absorption of THC in the body, intensifying the high. Mixing THC with alcohol also delayed the time it took for drinkers to feel impaired. The authors of the study believe such information is imperative for marijuana users to understand before they get behind the wheel.
Illinois residents charged with impaired driving may benefit by contacting a criminal defense attorney immediately after arrest. An attorney can often dispute the accuracy of tests used to establish impairment.