"Although this sector must be included in the cap, having a downstream point of regulation (i.e, the point were the emissions occur) is not workable. Owners or operators of vehicles, the sources that actually emit greenhouse gases is this sector, are too numerous to include in a cap-and-trade program."
Regulating the transportation sector's carbon emissions will probably work by estimating the contribution of individual drivers. The only question seems to be how much share of the cost of carbon to put on the gas and automobile industry. The white paper ends the transportation section saying "consumer demand is also an important piece of the puzzle that must be addressed."
Who do you think should pay for carbon pollution from cars? 100 percent of car's carbon pollution paid by the consumer? 50 percent paid by car industry and 50 percent gas industry? 33 percent car industry, 33 percent gas industry, and 33 percent consumer?
[Source: The House Committee on Energy and Commerce]