Jonathan M. Gitlin reports via Ars Technica: With a degree of coordination -- between vehicles, and with traffic infrastructure -- traffic chaos should theoretically be banished, and less congestion means fewer pollutants. Clemson researcher Ali Reza Fayazi has provided a tantalizing glimpse at that future, a proof-of-concept study showing that a fully autonomous four-way traffic intersection is a hundred times more efficient at letting traffic flow than the intersections you and I currently navigate. Because cars don't sit idling at the lights, Fayazi calculated it would also deliver a 19 percent fuel saving. Fayazi designed an intersection controller for a four-way junction that tracks vehicles and then uses an algorithm to control their speeds such that they can all pass safely through the junction with as few coming to a halt as possible. What makes the study particularly interesting is that Fayazi demonstrated it by interspersing his own physical car among the simulated traffic -- the first use of a vehicle-in-the-loop simulator for this kind of problem. Fayazi drove his real car at the International Transportation Innovation Center in Greenville, South Carolina, where a geofenced area was set up to use as the simulated intersection. Using GPS sensors, his car was just as visible to the intersection controller as the virtual autonomous vehicles that were also populating its memory banks. Ideally, Fayazi says he'd like to have tested it with an autonomous vehicle, but they are hard to come by, particularly in South Carolina. Instead, the intersection controller directly governed his speed in the study (as it did with the simulated vehicles), and this controller sent him a speed to maintain in order to safely cross the junction. Over the course of an hour, the intelligent intersection only required 11 vehicles to come to a complete halt. By contrast, when the simulation was run with a traffic light instead, more than 1,100 vehicles had to stop at the junction over the course of an hour.