A road ramp that uses passing cars to generate power has been developed.
*snip*
Plates in the ramp move up and down as vehicles pass over them, driving a generator.
"The ramp is silent, comfortable and safe for vehicles," Mr Hughes said. (the inventor of the ramp - afarensis)
Depending on the weight of the vehicle passing overhead, between five and 50kW can be generated.
One wonders how much energy the US could save by installing these ramps?