The Gas Guzzler Tax was created in 1978 when SUV, minivan and trucks were rarely used for non-commercial purposes. This is not the case today and the Gas Guzzler Tax needs to be reformed so it can continue to be effective at discouraging the production and purchase of fuel-inefficient vehicles.
More info on the Gas Guzzler Tax: http://www.epa.gov/fueleconomy/guzzler/