The study to analyze the effects of cannabis on driving performance found that it caused almost no impairment.
Researchers at the University of Iowa’s National Advanced Driving Simulator carried out the study, sponsored by National Highway Traffic Safety Administration, National Institute of Drug Abuse, and the Office of National Drug Control Policy.
“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 showed no/zero problems .
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.”
Cannabis, when taken in moderate amounts, seems to cause no driving impairment. In fact, it makes them drive safer or slower.
The study’s findings further illuminate the fact that alcohol is a much more dangerous drug than cannabis, and somehow the former is legal while the latter is not.