21100. Local authorities may adopt rules and regulations by ordinance or resolution regarding the following matters. (c) Regulating traffic by means of traffic officers (d) Regulating traffic by means of official traffic control devices meeting the requirements of Section 21400. (e) Regulating traffic by means of any person given temnporary or permanent appointment for such duty by the local authority whenever official traffic control devices are disabled or otherwise inoperable, at the scenes of collisions or distasters, or at such locations as my require traffic direction for orderly traffic flow. (h) Operation of bicyles, and, as specified in Section 21114.5, electric cars by physically disabled persons, or persons 50 years of age or older, on the public sidewalks.