Red, yellow, green ... and white? Smarter vehicles could mean big changes for the traffic light

Smarter vehicles could mean some of the most dramatic changes for the traditional traffic signal since the yellow light was added more than a century ago. Researchers at North Carolina State University and the University of Michigan are testing how to tap into the new technology found in the U.S. vehicle fleet to directly influence traffic signals and reduce congestion. The North Carolina State study even imagines a time when there could be so many self-driving vehicles on the road that a fourth light, a white one, could be added to allow them to lead the way. Michigan's research relies on connected vehicles made by General Motors and seeks to adjust retime the lights based on traffic.