French automaker Peugeot Citroen is claiming a major breakthrough in fuel efficiency due to a new vehicle design that replaces car battery with compressed air. The air tanks refill automatically and power a special hydraulic motor that, like an electric hybrid, works in unison with a regular internal combustion engine.

Peugeot says that it can achieve a fuel economy of up to 117 mpg using this technology. Car enthusiast Web site Motor Authority notes that the compressed air technology only adds 220 pounds to the weight of a car, which is well below the added heft of an electric hybrid. The maximum city speed is around 45 mph; the gasoline engine will kick in for highway speeds. Compressed air hybrids could hit the road by 2016.