Gasbuddy.com has some interesting information on gas prices including a great graphic located here. I put a smaller version on the right. The dark green equates to low gas prices, and the dark red equates with high gas prices. Because prices tend to change dramatically across state lines, I'm willing to bet that state gas taxes, regulations, and mandates are the major contributors to the differences.
South Carolina seems to have the cheapest gas, with Missouri close behind, even though they are not major oil producing or refining states. In the northeast, New Jersey seems to be an island of cheaper gas. What is really striking though is how California is solid dark red. The West Coast has dramatically higher gas prices than the rest of the U.S. In the northeast, New York and Connecticut stand out amongst the rest.
Because you can't read the key at the bottom right here is a list of select states and their average gasoline prices. Source here.
South Carolina - $3.85
Missouri - $3.85
Texas - $3.95
New Jersey - $3.97
Florida - $4.02
Massachusetts - $4.05
New York - $4.25
California - $4.59
California is paying 74 cents more than South Carolina. If your state wants to lower gas prices, they should try to not do what California is doing.
As much as I and other stereotype California's problems stemming from being more left-wing it doesn't really explain why Massachusetts isn't having such problems. Why California in particular is wracked by crisis after crisis is anyone's guess. Even when compared to other states that get ample media exposure it seems to have far more problems. Perhaps while the Northeast tends to be on the left it has more economic literacy due to it's heavy concentration of financial services.