Audi driver Mattias Ekström went to the limits of physics. In the U.S. state of Pennsylvania, the Swede tried out the capabilities of the new Audi A4 quattro*. Partner Red Bull prepared Canton Avenue in Pittsburgh with snow, slush and gravel. With a 37-percent grade, it is the world’s steepest residential street. On the slippery surface, Ekström easily chauffeured free skier Bene Mayr, snowboarder Heikki Sorsa and downhill mountain biker Aaron Gwin uphill, thanks to quattro drive. Subsequently, all four aces went downhill again using the sports equipment of their choice.