Buses along with rail networks and subways have dominated mass transit for decades. But a professor at the University of Minnesota came up with another alternative 30 years ago, and is still working to make it happen. Dr. Edward Anderson calls his idea Personal Rapid Transit or PRT. It looks like a slender version of an elevated train, with cars moving around town 16 feet above the ground. But unlike conventional trains, PRT uses small, electrically powered cars holding just one to three passengers. Dr. Anderson formed a company called Taxi 2000, to find investors, and build a prototype. To get a sense for the potential of this technology we spoke with Nacho Diaz, Director of Metropolitan Transportation Services at the Met Council, and Joe Lampe, Senior Vice President of Taxi 2000. Lampe says an analogy can help us understand how PRT works.