I saw this on the news the other day, a moving speed hump (up & down) to generate electricity to power street lights.
  Imagine this in the dark/wet/ any time at all.  
http://news.bbc.co.uk/1/hi/england/somerset/4535408.stm  Having visited their website    
http://www.hughesresearch.co.uk/index.htm   and looked at the video the idea of this being put to use scares the living **** out of me