Every time you argue against a higher gas tax.
There are thousands of bridges and tens of thousands of miles of roadway that need repair in this country right now. If the gas tax was high enough that money would be there, instead we borrow the money to subsidize the mechanism for burning petroleum.

There are ways to make cities "greener", and they don't require breakthrough technology.
New York City is the greenest place in America, the citizens of NYC have the smallest carbon footprint, the lowest automobile use, and the lowest heating costs in America. They walk more, use mass transit more and drive less.
If every citizen in the US used as much energy as a NYC resident, we wouldn't need foreign oil.
Because NYC was built before the automobile culture took over.
Now at one time when the US was a petroleum producing country, it may have made sense to promote the use of a domestic resource, but we are still promoting the use of petroleum, even though we need to borrow money to buy it from foreign sources.

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“ The subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state.”

Adam Smith , The Wealth of Nations 1776

"We have always known that heedless self-interest was bad morals; we know now that it is bad economics"
FDR's second Inaugural Address