DENVER (CBS4) – For the fourth time a Colorado state lawmaker will try to pass a law setting a limit for driving while high on marijuana.

The bill passed a review committee Friday and will be introduced in January. The proposal would limit drivers to five nanograms of THC per milliliter of blood. THC is the active ingredient of marijuana.

Similar bills have failed three times in Colorado. Opponents say medical marijuana users can have high THC blood levels and not be impaired.