Reading through many of the comments on this site, it has become apparent that many of you are dead-set opposed to this idea. I find that a little bit surprising with all that this idea has going for it. I must confess that my first reaction was: this is a brilliant idea! Are there potential issues here? Of course, but it has so much going for it that it would be foolish to ignore it.
Lets look at some of the problems:
Durability
Can glass stand up to punishment? We're not talking about house glass here. Anyone who has been to a hockey game knows how much abuse glass can withstand. Truth be told asphalt requires a ton of maintenance or it quickly deteriorates. Snowplows? Of course they will do some damage, but the question is: how much? They're already very hard on asphalt roads. Dirty? Well, we may find that street sweeper technology is effective. Having said that, if we do decide to implement this idea, I suspect that we would end up with a hybrid system. It would be foolhardy to suggest that one solution should fit all. I suspect that concrete or something will take the majority of the punishing loads with these panels along the shoulders or in parking lots or sidewalks. This idea may be more suited in certain climates and not others. At least to start.
Cost
Yes, this is more expensive than asphalt. But what are you getting for your money? If the inventor is to be believed, this surface would last 3X as long and would also incorporate the energy infrastructure of the nation. When people throw out trillion dollar numbers in regards to redoing the entire country, that's a bit of a scare tactic. Much of that money will have to be spent anyway repairing what we already have. If you eliminate some of the ideas such as the ultracapacitors and LED lighting, the costs could be brought down further.
Future Possibilities
To me, the most exciting aspect of the solar road is what sort of possibilities it opens up.
1. The electric car is coming. Imagine cars that charge while they drive, or at least when you park at a mall!
2. By incorporating the energy infrastructure into the roads, you eliminate the need for overhead power lines and the associated battles that accompany the building of new lines. Power lines are crucial for other renewables such as wind.
3. If done right, you start to build the mythical 'smart grid'
Certainly there are an abundance of problems that may occur, but, I haven't read anything on this site that is not solvable. Everything required to make this project work is already a proven technology. The only question-mark is if they can be combined and if governments and business will embrace this idea.