Actually, in California, the state sales tax on gas is 2.25%.
The excise tax per gallon went up 17.3 cents and the sales tax went down July 1, 2010.
Per the State Board of Equalization:
3. How does the Gas Tax Swap apply to motor vehicle fuel?
Beginning July 1, 2010, the retail sale of motor vehicle fuel is partially exempt from sales and use tax. The partial exemption applies to 6 percent of the current state sales and use tax rate. Therefore, retail sales on or after July 1, 2010 are subject to sales and use tax at a rate of 2.25 percent plus applicable district taxes.
Additionally, beginning July 1, 2010, the state excise motor vehicle fuel tax goes up by 17.3 cents ($0.173) per gallon. As of July 1, 2010, the new state excise motor vehicle fuel tax rate is 35.3 cents ($0.353) per gallon.
http://boe.ca.gov/sutax/gasswapfaq.htm
And what is the total amount of tax per gallon paid at the pump?
Also, how do you feel about congestion pricing? That will certainly had to the cost of motoring where it will be applied.