A new report indicates that a person who drives a car within three hours of smoking marijuana is nearly twice as likely to be involved in a serious car accident, causing an injury or death, than a completely sober driver. While the dangers of driving under the influence of marijuana receive much less attention that the danger of drunk driving, for a person injured by an impaired driver the pain and injuries are just as destructive.
The new report collected data from a variety of previous reports on the dangers of impaired driving. While the data showed a substantially increased risk of causing an accident for those drivers who used marijuana prior to driving, the risk for a driver at or above the legal limit for drunk driving was even higher.
Previous studies on the risks of driving after having smoked marijuana had not all been consistent, and the effects can be more difficult to measure as the level of impairment does not correlate with the presence of the active ingredient in marijuana as strongly as it does for blood alcohol concentrations.
Regardless of the cause of impairment, whether it be alcohol, marijuana, or even simply being overly tired. Any driver who is not able to fully concentrate on the road and traffic around them and make appropriate judgments in a reasonable amount of time poses a a serious danger to everyone on the road.
Source: Time, "Stoned Driving Nearly Doubles the Risk of a Fatal Crash," Maia, Szalavitz, Feb. 10, 2012