If you look at the
fuel taxes, you'll find that california's fuel taxes are not excessive - about $0.59 per gallon right now. However, AB 32, the first "climate change bill" passed by a state in the US years ago just implemented a rather large tax on fuel refineries operating in the state* which is pretty sneaky - consumers won't see this additional tax as an additional cost on their fuel since it's charged during refining, rather than at the pump. So the documents linked above specifically note that the effects of AB 32 are not included in the cost, though it's pretty clear that California's fuel prices are significantly higher than the national average, despite the taxes and actual fuel being largely the same.
So you can thank your government for jacking up your fuel prices in an attempt to save the earth, though it's nice of them to cleverly hide them so it's not immediately clear that it's an additional tax on consumers, and what's worse, disproportionately affects the poor.
Oh, and it enriches the state coffers by 5 billion a year too, so there's that.
*it's not clear if it affects refineries operating out of state making fuel intended for california, but I'm guessing that they've closed that loophole