The National Highway Traffic Safety Administration (NHTSA) has reported that what it calls drugged driving is rising and also a large increase in the number of drivers using marijuana and illegal drugs.
In a 2014 survey almost one in four drivers tested positive for at least one drug that could affect safety.
The number of weekend nighttime drivers with evidence of drugs in their system rose from 16 percent in 2007 to 20 percent in 2014. The number of drivers with marijuana in their system grew by nearly 50 percent. More than 15 percent of drivers tested positive for at least one illegal drug, up from 12 percent in 2007.
Additional findings were that drivers at a breath alcohol level of .08 percent were about four times more likely to crash than sober drivers.
Marijuana users were about 25 percent more likely to be involved in a crash than drivers with no evidence of marijuana use.