Colorado lawmakers will try a fourth time to pass a law setting a standard for what's considered too stoned to drive.
A transportation committee voted 10-6 Friday to introduce a bill next year. It would mean drivers with 5 nanograms or more of THC per milliliter of blood would be considered impaired to drive. THC is the psychoactive ingredient in marijuana.
Lawmakers have rejected the proposal three times.
Republican Sen. Steve King says he's bringing the bill forward again because public safety is at stake. But opponents worry medical marijuana users will be wrongly convicted of driving under the influence.
Colorado is among 16 states that allow medical marijuana use.
Nevada and Ohio have a 2 nanogram THC limit for driving.