Solar Energy from Roads?

I have been reading about using roads as a solar energy a lot lately. I personally like how people are thinking out of the box with these proposals. With thousands of miles of asphalt-roads that attract large amounts of heat, we might as well use that heat for something. There are two different proposals that I would like to talk about.

The first proposal would use our current road building practices and add an additional layer to the road. This additional layer would be a few centimeters from the surface and it would contain heat exchangers. The idea is that you would take the heat absorbed by the road and use water to heat buildings or to generate electricity. Now as interesting at this sounds, the amount of water needed for this project basically makes this a pipe dream, if you ask me. We can't use water, that we need for drinking, to sit in a huge pipe infrastructure under our roads. If we can develop a method to use a different liquid I would have no problem with this idea. (Source: Science Daily)

The other proposal that I am going to talk about required even more creativity. A company called Solar Roadways, has came up with a theory (still in early development phases) that would use the nations road system to generate electricity in a very interesting way. Basically the idea requires the road making process to be changed because the materials used would change. The roads would have glass solar panels built into them that would generate electricity. These panels would somehow have to be built into the road and have the strength to withstand traffic. Again, this is another very interesting idea and with some more work it could become a reality. (Source: Tree Hugger)

Keep in mind that even as cool as all of this sounds, the amount of money needed to actually put these ideas to work is in the billions of dollars. With a price tag like that and the fact that these are both very immature ideas we may never see any of these outside a lab. The other very important item to consider is the amount of energy each proposal would take to put into practice. Each proposal would require the roads to be repaved, new materials to be produced, etc... Let us hope that if nothing this sparks another persons mind to continue this work and to hopefully give us a working solar energy system to incorporate into our roadways.