Front-wheel drive “pulls” the vehicle forward. For this reason, a front-wheel-drive car is in principle more controllable and tracks better than conventional rear-wheel drive. On slippery roads in particular, the front-wheel-drive car has an advantage over rear-wheel drive because the weight of the engine is over the driven wheels, thereby increasing traction. Today almost 80 percent of the world’s passenger cars have front-wheel drive. Audi models feature either FrontTrak® front-wheel drive or quattro® permanent all-wheel drive.