This is how Audi connects its cars to traffic lights

Audi connects to the traffic light network of the city of Düsseldorf through “Audi Traffic Light”, a system that increases road safety.

Audi uses the “Audi Traffic Line” system to connect to the traffic light network of the city of Dusseldorf. With this system, safety, comfort and traffic efficiency are increased.

With Düsseldorf serving as the initial test site, the German manufacturer will be able to gather all kinds of relevant information to improve the future of autonomous driving.

How it works

The traffic light information system of Audi, “Audi Traffic Light Information”, consists of two functions: indication of the optimal speed for a green light, and time remaining until the traffic light turns green (Time-to-Green).

The GLOSA function calculates the ideal speed to achieve the so-called “green wave”. For example, if you drive at the speed indicated, the next traffic light will be reached while green.

Drivers do not have to accelerate unnecessarily, are not stressed and drive more safely. The GLOSA function can also suggest gradually reducing speed about 250 metres before the traffic lights so that the driver and the cars behind arrive at the junction when the light turns green.

If it is unavoidable to stop at a red light, a countdown shows the seconds remaining until the next green phase begins.

Drivers can relax, lift their foot off the accelerator and save fuel. Several studies conclude that city traffic is more efficient with networked traffic lights. In a pilot project, Audi was able to reduce fuel consumption by 15 per cent.

In the words of Andre Hainzlmaier, Head of App Development, Connected Services and Smart City at Audi:

“With the traffic light information system of Audi we want to improve driver comfort, increase road safety and encourage economical driving style for the future”.

Audi and its project partner, Traffic Technology Services (TTS), have developed a complex analytical algorithm that calculates precise predictions from three sources: first, the traffic signal control programme.

Second, real-time data from the traffic computer, from a combination of traffic cameras, detector loops embedded in the road surface, data on approaching buses or trams, and pedestrian push-buttons.

And third, a historical data record. The predictive algorithm improves itself continuously and learns, for example, how traffic volume entering the city changes in the mornings or when children leave nurseries and schools.

A feature that brings us closer to the future

The Audi vehicle fleet plays a decisive role in optimising the traffic light forecasts. “Cars send anonymous data to a Audi server, which checks whether actual traffic light changes correspond to the predicted data. Only after this is the traffic light information shown in the car”.

In the future, cities will also receive useful information about their traffic light infrastructure. The data will show, for example, whether cars stop unusually frequently at a particular intersection or whether the average waiting time is comparatively long.

Thanks to these advances, the German manufacturer can move closer to the future of autonomous driving, which in the coming decades could reach the coveted Level 5, that is, full autonomy.