The chief of police shall have the authority and duty to prohibit or restrict parking of vehicles along those parts of the streets constituting a part of the route of a parade, or at the point of assembly or dispersal of a parade, for a period of from three hours before its commencement to one hour after its dispersal. The chief of police shall post signs to such effect and it shall be unlawful for any person to park or leave unattended any vehicle in violation thereof. No person shall be liable for parking on any street unposted in violation of this section. (Ord. 1637 § 1, 1996; Ord. 1627 § 1, 1996).