"The United States federal excise tax on gasoline, as of February 2011, is 18.4 cents per gallon and 24.4 cents per gallon for diesel fuel. In January 2011, motor gasoline taxes averaged 48.1 cents per gallon and diesel fuel taxes averaged 53.1 cents per gallon."
The latter figures include state taxes, you can't blame the "elite academics" for that one. The FED is only milking 18.4-24.4 cents per gallon on your fuel. The rest is the whim of the guy controlling the spigot. Last time I checked the oil companies don't fix roads or bridges.
Meanwhile, the list of top revenue companies in the world are filled with OIL companies. They are exporting the out-of-spec diesel because it makes them more money. This comes at the cost of domestic diesel prices.