One of the most satisfying things in an NYC motorist's life is coming over the Queensboro Bridge and heading south on 2nd Avenue late on a weekday night. Through proper timing and judicious use of the accelerator, you can catch a wave of green lights for three miles, from 59th Street all the way down to Houston.
Audi's Smart City Traffic Light Assistance System, if realized, could convey this sensation to millions—while cutting a car's emissions by some 15%. While it's not designed to let you beat lights per se, what the system does is receive information beamed from surrounding traffic lights, then crunches that data with your car's location and speed to present the precise timing between lights. Check it out:
The obvious hurdle is that it requires a grid of "smart" traffic lights that can beam data--but ideally this is the way cities should be going. And the upshot is that the system can be retrofitted.