The LA system is probably the most comprehensive today, but it’s not the only one. In Pittsburgh, three foundations have worked with Carnegie Mellon University to create coordinated lights for the busy East Liberty part of the city. They’re claiming 40 percent reductions in vehicle wait times, 26 percent cuts in travel time, and 21 percent drops in emissions from idling cars. The best improvements were at mid-day, with 32 percent improvements in travel time, and a 52 percent reduction in the number of stops. The next step is expanding the pilot program, the city said last year.

 “The idea is to optimize the movement of traffic through each intersection, and the results have been startling,” said Allen Biehler, executive director of Carnegie Mellon’s University Transportation Center.