A great news for marijuana users made the headlines as the first study regarding the "effects of cannabis on driving performance" emerged.
As per the Free Thought Project, researchers at the University of Iowa's National Diving Simulator did a study which was sponsored by National Highway Traffic Safety Administration, National Institute of Drug Abuse, and the Office of National Drug Control Policy stated that cannabis does not cause impairment in driving performance, which was compared to the impairment caused by alcohol consumption.
"Once in the simulator-a 1996 Malibu sedan mounted in a 24-feet diameter dome-the drivers were assessed on weaving within the lane, how often the car left the lane, and the speed of the weaving. Drivers with only alcohol in their systems showed impairment in all three areas while those strictly under the influence of vaporized cannabis only demonstrated problems weaving within the lane. Drivers with blood concentrations of 13.1 ug/L THC, or delta-9-tetrahydrocannabinol, the active ingredient in marijuana, showed increased weaving that was similar to those with a .08 breath alcohol concentration, the legal limit in most states. The legal limit for THC in Washington and Colorado is 5 ug/L, the same amount other states have considered."
As per the studies, mixing alcohol and cannabis however can cause further damage which isn't safe, but using cannabis alone does not cause impairment. And some users, argued that it cannabis consumption makes then driver safer, more cautious and slower.
Additional studies then cited that:
"The study also found that analysing a driver's oral fluids can detect recent use of marijuana but is not a reliable measure of impairment. Everyone wants a Breathalyzer which works for alcohol because alcohol is metabolized in the lungs but for cannabis this isn't as simple due to THC's metabolic and chemical properties."
The Westword and Alter Net websites provided additional support in regards to the study.