text: why do you think you would not want to reduce the friction involved in using a winding road?   without friction , a car can't cahange direction. car wheels are similar to sneaker soles, think about trying to change direction when on ice. with low friction, it is easy to maintain constant velocity, but aceleration requires force, and the only forces in a car are friction between the tires and the road. if you want to go fast in a straight line, low friction is good once you are going fast, but you couldn't even get any speed without friction. in a winding road, you need to keep changing direction, so you need to accelerate in different directions.