robomatic, I agree with you about the gas tax.

On the subject of "real costs", there are a number of hidden costs that are frequently not factored into the overall equation. One such hidden cost is the cleanup costs and the overall negative impact on the enviornment of oil spills. Also, the impact on the environment of the products of internal combustion. And of course, the costs (both in terms of dollars as well as in terms of loss of human lives) of the wars that are needed in order to secure a steady oil supply. Right now, the most environmentally friendly as well as cost competetive fuel source would seem to be bio-deisel used in hybrid vehicles. But if a way to produce reliable energy is found using hydrogen fuel cells, taking into consideration the cost to the environment of combustion of any sort, the fuel cell technology might prove to be the better one in the long run.