Question

How does a smoother surface affect braking distance

Answer 1

Friction has to do with this.  If you have a smoother surface than another surface, the smoother surface will contain less friction.  Friction is an opposing force against a moving object.  If there is less opposing force towards a moving object, there is less friction.  If you have a smooth road, cars won't break as fast as they would break on bumpy roads, because bumpy roads have more bumps, creating more friction.  I hope that helped.  :D