Self-Adapting Traffic Lights

If you were part of a group of cars approaching a red light, inexpensive traffic-flow sensors would detect your group in advance and turn the light to green.

"Gershenson finds that, in his simulations, adaptive request control is the most efficient for low traffic densities, but works poorly for dense traffic. Adaptive phase control also works well at low densities, and doesn't clog up at high densities either; so on average, it is the best method overall. Both schemes are typically around 30% more efficient than the non-adaptive ones."