The American Fuel Affordability Act repeals federal excise taxes on diesel fuel, which are currently applied at the point of sale and distribution. The bill eliminates these taxes effective immediately upon enactment and requires the Treasury Department to compensate the Highway Trust Fund and the Leaking Underground Storage Tank Trust Fund for the lost revenue so these programs can continue operating. Additionally, the legislation creates three new tax incentives for oil refinery companies: a 35 percent investment tax credit for construction of new refineries between now and 2032, a five-cent-per-gallon production credit for gasoline and diesel made at newly constructed refineries, and a permanent special depreciation allowance for refinery equipment. The bill is designed to lower fuel costs for consumers and businesses while encouraging domestic refinery expansion, though it will reduce federal tax revenue that would need to be offset through other government revenues or spending cuts.