An interesting article on solar

I read this article recently on using roadways to generate power by using strong solar panels for roads. An interesting concept.

http://crispgreen.com/2010/10/solar-roads-double-as-power-grid/

Interesting article on Solar Roadways. Its totally a new concept about the utilization of solar energy in an effective manner.
I never heard about such road ways using solar energy. So are these solar roadways practically possible to construct or it is already implemented somewhere??
Loved that video also, would like to know more about the same.