Marijuana users may face hidden driving danger that standard tests can miss
Cannabis edible users registered THC levels nearly 10 times lower than smokers despite similar driving impairment, exposing a potential road safety gap.

TL;DR
- Driving after consuming cannabis edibles can cause significant impairment, even with THC levels below legal limits.
- Edibles are absorbed more slowly than smoked cannabis, leading to impairment at lower blood THC concentrations.
- A study found that drivers who consumed 10- and 20-milligram THC gummies showed impaired lane control, slower reaction times, and inconsistent speed.
- Blood THC levels in impaired edible users were significantly lower than those in previously studied smoked cannabis users, yet impairment was comparable.
- Standard blood tests may fail to identify unsafe drivers who have consumed edibles due to the delayed absorption of THC.
- Policymakers and law enforcement face challenges in developing reliable roadside tools to detect impairment from edibles.