It is my understanding that California uses slightly less petroleum based fuel on a per capita basis than the rest of the US, due to a very slightly higher mileage than average vehicle fleet. California has more natural gas vehicles than the rest of the country, as well. California is only about 10% of the population and only uses only about 10% of the nations petroleum fuel? Transit overall is still only about 3% of all trips. California does use considerably less (virtually zero) oil for electrical generation.