Pittsburgh, meanwhile, has strong existing ties with local universities when it comes to transportation. At Carnegie Mellon, researchers affiliated with the Traffic21 Institute, and an initiative known asMetro21, work on technology that has already been tested in the city. One of the proposals in Pittsburgh’s Smart City Challenge application calls for wider deployment of a traffic signal control system that came out of Traffic21, known as Surtrac. It uses machine learning algorithms to optimize when traffic lights change to red or green and has already been installed at a number of intersections in Pittsburgh. At intersections where the system is in place, vehicle wait times have gone down by 40 percent and emissions have declined by 21 percent, according to Stan Caldwell, executive director at Traffic21. Wider deployment could lead to further improvements, Caldwell noted. “The more information the city can get, the smarter we can help it become from our research,” he said.