These workers are installing a system that works like radiant flooring in reverse. The pipes within the road capture the waste solar heat from roads and transfers it elsewhere, so it can be used to heat homes... among other things.
The system comes from a Dutch company with a not so link-friendly website. Look for Road Energy System in the Product section of their website to read the details.
Among other potential benefits, like free heat, the system helps moderate seasonal temperature swings in roads, which means they should last longer with less cracking. And in extreme climates, this is a more economical way of heating the road to prevent frost and ice.
Our expert sources say this is still experimental technology, but we're excited: if there's one thing there's plenty of in the US, it's roads, parking lots, and driveways. Any way to use roads to acheive lower energy use is worth investigation. For those to whom cost is not a factor, we're wondering how easily the system could be integrated with the heated, energy-wasting driveways relatively common in luxury housing developments in the upper Midwest and Rocky Mountain states.
via EcoGeek via Berkeley CBE