No person upon roller skates or riding in or by means of any coaster, toy vehicle or similar device shall go upon any roadway, except while crossing a street on a crosswalk. When so crossing, the person shall be granted all of the rights and shall be subject to all of the duties applicable to pedestrians. This section shall not apply upon any street while set aside as a play street as authorized by ordinance of this city.
(`90 Code, § 20-7)