create a variable tax on transportation fuels creating a floor price as a means to stimulating fuel efficient technology

A variable tax that puts a floor price on fuel would raise revenues for use in stimulating green technology and add the incentive to consumers to demand more efficient technology in transportation. The tax would, for example, set a floor price on gasoline with the difference between the cost plus state taxes being the federal variable tax. Everyone would know the long term cost of fuel which would provide greater certainty in personal and business planning.