Taxes on a gallon of gasoline include the retail costs at the pump (in Washington, there are federal, State, and county taxes for this), the taxes for drilling the crude (federal), and taxes for processing, and taxes for shipping stuff around.
For a typical station in King County, WA; total taxes come to about $1.05 per gallon. This includes the drilling tax of 18.5 cents, the production tax of 14 cents, the federal retail tax of 18.4 cents, the State retail tax of 49.4 cents, and the county tax of 4.94 cents.
Currently, Inslee is considering an additional tax of 46 cents/gal for cap and trade.
While Washington State currently has the highest State gas tax in the nation, the SDTC has the highest combined taxes per gallon, due to county and local taxes, in some places such as Los Angeles coming to $1.29 per gallon. Not to be outdone by Washington, King Newsom is also considering adding a hefty additional tax.
Meanwhile, in nearby Idaho, they have a State gas tax of 32 cents/gal and no county taxes, bringing that total to only $0.82 /gal, which is why Idaho fuel prices are lower than Washington.
Sources: federal and various State revenue departments, and State and county laws.