The whole point is that legalization is not going to improve those numbers. It's not okay to drive stoned any more than it's okay to drive drunk, or on Ambien, and anything else that impairs common sense.
I have an ex named Michelle who now thinks it's perfectly ok to drive down the road smoking a pipe full of weed because it's legal now in Colorado. She didn't before because weed was illegal. She's a lousy driver when she's straight and weed will not improve her skill.
Bottom line here - smoke it all you want at home just stay the f&%k off the road!
The whole point is that legalization is not going to improve those numbers.
No, the whole point is the Reefer Madness brigade cooking the books as usual. (And legalization just might improve those numbers, by eliminating the incentive to smoke it as soon as you've got it in order to avoid a possession arrest.)