Most of the things we own are designed for the purpose for which we use them, but cars are designed to cross deserts at high speeds and race round bends on empty roads.
The result is danger, noise and unnecessary pollution as vehicles accelerate competitively, brake at the next obstruction then accelerate again, while averaging only the speed of a bicycle on a typical short journey. Collectively this behaviour is irrational, but the individual driver feels under pressure to join in whether he likes it or not.
Low-powered vehicles purring along at safe speeds would be a world away from our present day `race-bred' machines. Low acceleration and speeds would result in smoother traffic flows with less bunching and no serious road blocking accidents. It would become safe for children to walk to school, and more people would use their bicycles, resulting in a voluntary reduction in the number of cars on the road without the need for more buses.