Re: Wasn't there something similar for car parks a few years back?
The problem with that is that the vehicle would seem to be going slightly uphill, or like driving through molasses. Thus they would use more fuel
You could combine that with a speed camera - rather than sending a paltry fine through the post, you just extract all the excess energy from a speeding car, slowing him to the speed limit and also extracting valuable power...
Vic.