The number of U.S. drivers under the influence of alcohol is steadily dropping, but the use of illegal drugs by drivers is on the rise, new data from a U.S. Transportation Department survey showed on Friday.
While about eight percent of drivers during weekend nighttime hours had alcohol in their system, only one percent were found with breath alcohol content higher than 0.08 percent- the legal limit in every state, according to the survey by the Department of Transportation's National Highway Traffic Safety Administration (NHTSA).
This is a marked reduction from the 30 percent in the 2007 survey and down 80 percent from the first survey in 1973, the survey stated.
Despite that, the use of illegal drugs and medicines that can impair driving capabilities is on the rise.
The number of weekend nighttime drivers who were found with drugs in their system jumped from 16.3 percent in 2007 to 20 percent in 2014.
The number of drivers with marijuana in their system grew by nearly 50 percent.
The survey also found that marijuana users are more likely to find themselves in an accident, mostly because they are more likely to be in groups at higher risk of crashes, the NHTSA survey said.