Pot is produced in California but not yet legal for recreational use. If legalization does come, the law will grapple with setting standards for how long users should wait before driving.
Unlike Washington and Colorado, California hasn't yet legalized recreational marijuana use. But the day is coming when a new ballot measure is put before voters, even though the most recent legalization proposition failed in 2010.
We seem to be headed for a world in which the American West is receptive to making pot legal. There are incentives for states to go down this road, including the ability to tax pot and avoid having to spend much enforcing anti-pot laws (in 2011, I wrote about the economics of legalizing pot).
But what should be done about pot users getting behind the wheel?
It's against the law to drive while impaired in California, regardless of the impairing substance — booze, pot, or other drugs. If you get arrested for driving while stoned, it's up to a blood or urine test to determine whether there's enough THC (Tetrahydrocannabinol, the stuff in cannabis that get users high) present to prosecute.