The gasoline tax would achieve the 10 percent reduction
at the lowest cost of the three policy alternatives examined.
Under the demand and supply responses that CBO
assumed, a 46-cent-per-gallon tax increase would achieve
the targeted reduction and would impose a welfare cost of
$2.9 billion per year—3 percent less than the cost of
CAFE standards with trading and 19 percent less than
the cost of the standards without trading.