That’s the good news. The bad news is that there are other drivers out there under the influence of some kind of narcotic. Only as recently as 2007 did NHTSA begin to screen for substances other than alcohol, and its findings were not pretty.
According to NHTSA, 16.3% of nighttime weekend drivers tested positive for some type of drug — 8.6% were impaired by marijuana, 3.9% by cocaine and 3.9% by over-the-counter or prescription drugs. That means there are people who wouldn’t get behind the wheel after drinking, but who feel perfectly fine about it after doing cocaine or smoking pot.
NHTSA will conduct further studies to figure out how to test more accurately for drug use and find ways to discourage people from engaging in the kind of behavior that can risk lives on the road.