If you're speaking about the federal gas tax which goes to the Highway Trust Fund[1], it's currently $0.184 per gallon of petrol and $0.244 per gallon of diesel.

There are also state gasoline taxes, vehicle weight fees (for commercial interstate trucks) registration fees, and tolls[2].

1. https://en.wikipedia.org/wiki/Highway_Trust_Fund 2. https://www.citylab.com/transportation/2017/07/us-transporta...