No person shall ride or lead a horse, or ride a bicycle, or operate or ride a skateboard or motorcycle or roller blades or roller skates or foot-powered scooters over and along public sidewalks within the above-defined business district.

These regulations shall not apply to wheelchairs and other human-powered devices necessary to a person to be ambulatory. These regulations shall also not apply to any child who is riding a bicycle with training wheels attached in addition to regular wheels provided that the child is accompanied by a parent or guardian.