France's Enrovia is developing a temperature sensitive concrete varnish that will change color for certain conditions:

"Problems caused by disappearing traction when roads get icy will be solved when we all get our flying cars - it is the 21st century, after all. Until that long overdue promise is fulfilled, we're all relegated to putting rubber to the road to reach our destinations. The way winter road conditions are currently mitigated involves lots of salt and many trucks. The trucks are pretty much necessary for removal of heavy precipitation, but salting exacts an environmental, as well as financial price. Motorists, too, could benefit from a warning that road surfaces are less than optimal. To that end, France's Eurovia is developing a temperature-sensitive varnish that changes color to provide a visual indication to all road users that the pavement is freezing. Once it warms back up again, the varnish returns to its default hue. Durability trials are underway in several areas of France that experience severe weather, and if the coating holds up well, we could all be watching out for pink stripes in the winter. "

By Dan Roth
Source: Autoblog via Coolhunting