Road Marker Marks You
If you could make a reflective road marker (a "road stud", in the jargon) that contained a small solar cell and battery, you would be able to: A) power a LED at night to provide lit lanes, not just reflection; B) monitor for fog or water on the road surface; C) monitor the temperature to detect ice; D) use infrared ranging and embedded cameras to detect and report the license number of anyone speeding on the road; E) All of the above. If the company can make them cheap enough, they'll be everywhere in a few years.
You'd need a candle truck full of these to be useful.
-----
Pretty Bad Privacy (PBP) Public Key
6