I don't see *exactly* how it's the fault of vehicles, per se. Perhaps a better way to tweak the collective nose of California government is for the refiners of petroleum fuels to stop selling their products in the state.
How long do you think it'll take the State to convert to solar (or hydrogen, from electrolyzed water) powered cars on their own volition?
I thought so too.
Of course, fusion reaction of seawater would be exceptionally clean and non-polluting, if only they could get that whole magnetic plasma chamber containment thing down.
And what about all those California cheese commercials? Bovines produce as much methane as those protected wetlands do, if not more.
Putting up a wall and proclaiming it 'crazy monkey land' is starting to sound better and better. Unfortunately, it'd play into the hands of the Aztlan group, who would create another third-world hellhole on our western border with environmental problems worse than the provinces surrounding old Soviet weapons plants.