(A) (1) The City Manager, subject to any directions which the Council may give by motion or resolution, is hereby empowered to make regulations necessary to make effective the provisions of the traffic ordinances of the city and to make temporary or experimental regulations to cover emergencies or special conditions.
(2) No temporary or experimental regulation shall remain in effect for more than 90 days.
(B) The City Manager may have traffic-control devices tested unto actual conditions of traffic.
(`90 Code, § 20-3)