These two Audi vehicles were designed to interact with intelligent traffic lights on the streets of Ingolstadt, Germany.

Photo courtesy Audi of America

Intelligent Traffic Lights

The evolution of traffic lights is a journey from mindless automation to increasingly intelligent, fluid traffic management. The simplest traffic lights operate on timers, giving each flow of traffic a predetermined period of red, yellow and green. These models are frequently used in cities, where traffic flows are predictable if not consistent. As such, they may be set up to handle rush-hour surges, but might be powerless against atypical traffic on a Sunday afternoon. Other traffic lights require a vehicle to trip a detector in order for the signal to change. In both examples, the traffic light system responds only to programming or minor traffic detection.

As more and more vehicles take to the streets, cities face greater traffic congestion -- to the point where simply building larger roads is no longer a valid fix. Instead of adding more lanes, traffic engineers and scientists have worked to create intelligent transportation systems. These systems involve various regulating measures that can be divided into intelligent infrastructure and intelligent vehicles. Instead of simply managing vehicles at a specific intersection or on a particular road, the system would regulate a city's collective traffic flow in all its stops and surges. Under ideal circumstances, traffic infrastructure would not only manage the vehicles on the road, but stay in constant communication with the cars' onboard computers.

­Intelligent transportation systems involve numerous technologies, some already widespread, others merely developing. On the infrastructure side, intelligent traffic lights play a major role in keeping vehicles flowing along, and feature prominently in Audi's Travolution system. The city of Ingolstadt boasted 46 intelligent traffic lights during the summer of 2008, with plans for 50 more throughout the city. These lights are networked together, which reduces stopping time for vehicles. Again, the idea is not to simply create clockwork barriers for traffic to filter through, but to manage the flow of traffic for maximum efficiency.

The Travolution system also features an intelligent vehicle component, and this is where the system really appeals to hypermilers. The traffic lights don't merely communicate with each other; they communicate with the vehicles themselves -- in this case, specially augmented Audis. During the summer of 2008, the company had two vehicles on the road, but plans to add an additional 20 vehicles.

How does Travolution change the driving experience on the streets of Ingolstadt? Get behind the wheel on the next page.