Both ethanol and THC have been shown to impair driving. But ethanol has a far shorter half-life than THC, making a determination of when a person became intoxicated by THC far less clear. A new study reduces that uncertainty.
marijuana and driving
There is some truth to the urban myth that those high on marijuana tend to drive more slowly and at greater distances from other cars. Whether out of an old-time fear of being pulled over or because of some impairment of their perceptions.  With eighteen states (and the District of Columbia) with recreational pot sales, and an inability to determine the presence of marijuana as an intoxicant, as we do for alcohol, there is rising concern about marijuana’s impact on traffic accidents and fatalities. Here is the latest data.