The Israelis have figured out that if you implant piezoelectric crystals into asphalt roadways, you can extract energy from them as vehicles pass over them as they drive along. I suspect that the supporting infrastructure will render this idea impractical. Imagine the wires required to connect all the piezo's together, embedded into the asphalt, and subject to damage from potholes.
Assuming a high level of efficiency, a kilometer of road could conceivably power some 40 residences. Assuming a more modest level of efficiency, and also assuming that the speed of the vehicles passing over has some effect on the output, I could see the six-mile stretch of I-25 that I drive twice daily supplying enough power to recharge my cell phone. Eventually.
If we're going to play with the roadways, let's see if the rumble strips which show up on the shoulders of some roads, can be artfully applied so as to cause your tires to vocalize "caution....shoulder" or some such as you pass over them.