(A) The city engineer, by and with the approval of the chief of police, is empowered to make regulations necessary to make and enforce temporary regulations to cover emergencies or special conditions.
(B) The city engineer, by and with the approval of the chief of police, may make temporary rules regulating traffic or test traffic-control devices under actual conditions of traffic. No experimental rule regulating traffic shall remain in effect for more than 90 days.
('64 Code, § 21-30)