The federal gas tax has been stuck at 18.4cents¢ a gallon since 1993. Today, Americans are driving fewer miles, and vehicles have become more fuel-efficient. Less gas consumption means less gas-tax revenue to repair the nation's roads. Source: Bloomberg News, July 17, 2014 Would a tax per mile driven by more efficient or less efficient than a tax per gallon of gasoline? Which tax would be more regressive? Explain your answers.

1. A Tax per mile driven would be more efficient than a tax per gallon of gasoline.

2. A tax per gallon of gasoline is more regressive.  The tax is based on a fixed dollar per gallon since 1993.  instead of being based on a percentage per the price of gasoline per gallon.  With the current rate, the price of gasoline per gallon may even be less than the tax.  One can then ask, "what is the purpose of the tax?"  Is the tax a road tax or a per gallon use tax?

Explanation:

When the federal gas tax remains at 18.4 cents per gallon for a very long period, the tax can be described as regressive as it does not take into consideration the trend that Americans are driving fewer miles, and vehicles have become more fuel-efficient.  This means that the gas tax is not fit for purpose.  If its purpose is to generate revenue for road repairs, then instead of a gallon tax, government should institute a road use tax.

i might look it up later.