I'm not aware of the US-situation, but as this article is about Germany, I can tell you that 2/3 of the german oil price are taxes. We usually pay $6-7 per gallon.

The gas tax at the pump is somewhat complicated here as each state does their own tax. This can create interesting price differences as you drive across state lines. Also, we have a change over in the summer to a "summer blend" of gas which causes a change in prices (usually upwards) as I believe it's more expensive to produce.

https://taxfoundation.org/state-gasoline-tax-rates-2017/