One of life's small but satisfying pleasures is hitting the sweet spot while driving across town and catching all the green lights. At the moment, having that happen is a matter of luck, but Audi is developing a system that will make never getting caught by a red light an everyday thing as a way of speeding up traffic while improving fuel efficiency and cutting emissions.

Driving through a string of green lights isn't a question of gremlins or clean living, but of timing. Modern traffic signals operate on a system of preset timers. Sometimes these change depending on the time of day or, as is increasingly common, because the traffic system reacts to changes in the pattern of car movements. In other words, the trick to an uninterrupted journey is to figure out how the lights are timed at that moment and drive at the right speed, so you always hit the intersections when it’s green.

The Audi system works by taking the guesswork out of the equation. Using Audi connect and the Multi Media Interface (MMI) system, the car uses the internet to contact the area’s central traffic computer and asks it for the automated traffic light sequences. From these, the system calculates the best speed needed to hit as many green lights as possible. This speed, as well as red, green and amber icons, are displayed to the driver via the Driver Information System (DIS) located in the central instrument cluster. If the car is already at a red light, it provides a countdown until green and overrides the start/stop mechanism to bring the engine online five seconds before it’s time to go.

One bonus of this is that not only will the system speed up traffic, but improve fuel economy and reduce emissions, since the biggest enemy of fuel efficiency is the constant braking and acceleration of city driving. If the cars keep running, that saves fuel and cuts pollution. Audi says that if used consistently, the system could produce a 15 percent reduction in carbon dioxide emissions and save 900 million liters (238 million gal) of petrol annually in Germany alone.

According to Audi, the system, which would be integrated into its Audi connect infotainment system, is production ready and could be fitted to every Audi model currently in production, pending the approval of local legislation.

A prototype of the system was shown off at January's Consumer Electronics Show in Las Vegas in an Audi A6 Saloon, which ran on the city roads, with testing continuing there using 50 sets of traffic lights. In addition, Audi is also testing the system with about 60 sets of traffic lights in Verona, Italy, while 25 cars are being tested in Berlin with 1,000 lights. Audi has yet to release performance figures, but it will be interesting to see how the system operates in the real world.

Source: Audi