Colas, along with the Ray Foundation and the Georgia Department of Transportation, has dedicated an 18-mile stretch of Interstate 85, known as "The Ray C. Anderson Memorial Highway" or "The Ray," for experimentation in solar-roadway advancements. The project can also now boast a one-kilometer stretch in Normandy, France.
Colas has been working on the Wattway since 2009. The concept involves gluing a quarter-inch-thick slab of photovoltaic material on top of a road, and the company says the material is strong enough to handle the weight of heavy-duty trucks. Colas last year publicized its work with INES (France's National Institute for Solar Energy) and their collective goal is to eventually add about 600 miles worth of solar roadways in France. Such installments aren't cheap, as the cost of the first kilometer of Wattway in France has been estimated at more than $5 million.
While the Wattway's accomplishments may still appear modest, the company seems miles, or kilometers, ahead of the Netherlands' SolaRoad project. That company is developing solar-energy-producing bike paths, and in 2014 installed a 230-foot-long ribbon of path covered in tempered glass and solar panels in its home country. That test bed cost a tidy $3.7 million to install. SolaRoad added another 20 meters to that path last fall, and last year reached an agreement to test out a solar-material-covered path in Lebec, California, but the project remains in its infancy.