It's reported that researchers in Michigan have concluded that connected, communicating vehicles would ease through intersections far more efficiently that at present meaning twice as much traffic could use our roads if we ditched traffic lights in favour of cars that communicate with each other at junctions.
A study co-authored by MIT researchers, based on mathematical modeling, claims this kind of traffic-light-free transportation design would keep traffic moving smoothly as our roads become ever-busier.

Sensors

Researchers examined a scenario in which vehicles use sensors to remain at a safe distance from each other as they move through a four-way intersection. By removing the waits caused by traffic lights, these so-called Slot-based Intersections (SIs) speed up traffic flow.
Read more at http://www.techweekeurope.co.uk/e-innovation/ditch-traffic-lights-in-favour-of-connected-cars-say-researchers-188130#tBCKCHfAVjKZ5qhR.99