About 14% of Washington state drivers with children in their car recently used marijuana,
a rate similar to those without children.
Researchers stopped just over 2,000 drivers on Fridays and Saturdays in 2014 and 2015,
taking voluntary fluid, blood and breath samples and asking them to fill out questionnaires.
Among drivers with children in the car, 0.2% had some alcohol in their system and
none were above the legal limit compared to 4.5% and 1%, respectively, among drivers
About 14% of drivers with a child in the car tested positive for tetrahydrocannabinol
(THC), the active ingredient in marijuana, compared to 17.7% of those without a child.
The difference is not statistically significant.
Most of those surveyed said they believed marijuana impaired driving. Among those,
8.9% with a child in the car tested positive for THC. Among who didn’t think it was
risky, 40.6% of those with a child in the car tested positive. Both figures were statistically
the same as for drivers without a child in the car.
Authors noted the presence of THC did not prove a driver was impaired.
“Nevertheless, the possibility that at least some of those drivers were impaired is
a source of concern, particularly given the wave of legal and social norm changes
reshaping the use of cannabis in the country,” they wrote.