[bls]

It isn't the same amount of fuel. If the car's engine is going to power something else besides the car, it is going to have to work harder.

Imagine the car is running in a vacuum and gets 30MPG. Now, add normal air resistance. It will not get 30MPG anymore. Now, add something else that further increases wind resistance. The car will get even fewer miles per gallon.

[fauigerzigerk]

That assumes that air resistance is indeed increased. I doubt that, but I'm not a physicist... Maybe it depends on what is next to the motorways now?

[bls]

Wind power works by creating wind resistance. In order for there to be _less_ air resistance with them installed, they would have to be replacing something that caused even more wind resistance. But, that seems unlikely.

[fauigerzigerk]

It puzzles me that some people deem it necessary to down-mod what is basically a question.