Is Piezoelectricity Worth the Cost?

[Kermit]

I just recently learned of something called piezoelectricity, and am rather interested by it. If you are unaware of what this is, basically is a way of generating energy through mechanical motions such as walking, cars driving over a platform, ect. (Here is a direct link to a video explaining it http://www.youtube.com/user/MrKeepthelightson#p/p/A11A9410F65F012F/4/oIObdaN-HCE)

I can see it being worth the cost if it is simply worked into the construction of new roads, as that is where it can make the most energy. I can also see it being retro fitted into place like dance clubs or airports. However the cost of retrofitting existing roads and bridges with this would be astronomical, and what I believe to be completely prohibitive when one studies the expected output even over a long time line.

So I guess my question is, do you think this is something we will ever see in the road systems of North America, or will this technology be reserved for newly developing urban landscapes, or do you think this will not take off at all?

I look forward to hearing everyone's opinions on this one.