According to the inventor:
Solar Roadways is a modular paving system of solar panels that can withstand the heaviest of trucks (250,000 pounds). These Solar Road Panels can be installed on roads, parking lots, driveways, sidewalks, bike paths, playgrounds… literally any surface under the sun. They pay for themselves primarily through the generation of electricity, which can power homes and businesses connected via driveways and parking lots.
Here’s the Indiegogo crowd funding campaign, which, at the time of this writing, has exceeded it’s $1 million goal by nearly 50%. On that page you’ll also find a number of more informative (and less… enthusiastic) videos.