Audi dynamic steering

With its harmonic drive gearing—a compact, three-piece gearset previously used in lunar rovers—the 2009 Audi A4 modifies the steering ratio in response to the car’s speed. When you’re parking, one turn of the wheel covers the full range of motion. At highway speeds, the same range takes four turns. The system can also detect any potentially dangerous motion and help you correct it; if electronic sensors determine that you’re going too wide into a sharp turn, they will tighten up the steering ratio so you can get back on course with a smaller movement of the wheel. The system works three times as fast as other electronic stabilization systems. audi.com