London News: Hi-tech sleeping policemen that use the pressure of passing cars to create power are to be tested by Ealing Council | london life | thelondonpaper Discuss...
If the plates are used in places where you want to slow down traffic anyways (eg replacing speed bumps), then it's a good idea. But for other places, it might actually be a wasting more energy than just using electricity normally.
I saw this whole idea proposed and discussed somewhere else a few years ago. In a way it is a direct (localized) tax on those that use that particular road. I have to imagine that it would create some extra noise as the cars drive over the generator.
Yes, what they said. This is a much better idea: LED-encrusted speed bump flattens out when you're not flat-out - Engadget