Those taxes are supposed to pay for highway repair, which is why they were originally passed. Now it just goes into general funds and therefore gets spent on un-needed wars and bank bailouts.
But yes, the oil companies make roughly 9-10% profit which on $3.00/gallon gasoline is not quite 30 cents per gallon profit.
With the new Ohio tax as of July 1 Ohio taxes gasoline at 28.01 cents/gallon, add in the federal tax of 18.4 cents/gallon and you have the government making 46.41 cents/gal here in Ohio while the oil company makes 30 cents.
Ohio was one of the lowest state tax (next to Alaska and Missouri) before this hike. Now we are more around the 15th cheapest state now.
California and Pennsylvania are the highest, which is why if I am traveling east I try to fill up in Ohio before I start driving through PA.