The city manager shall have the power and duty to place and maintain, or cause to be placed and maintained, official traffic-control devices when and as required as follows:
A. 
To make effective the provisions of the city traffic regulations;
B. 
Whenever the city manager deems such traffic- control devices to be necessary or proper to regulate traffic or to guide or warn traffic, based upon traffic engineering principles and traffic investigations and in accordance with such standards, limitations and rules as may be set forth by ordinance or resolution of the city council;
C. 
Whenever the Vehicle Code of the state requires for the effectiveness of any provisions thereof that trafficcontrol devices be installed to give notice to the public of the application of such laws.
(Ord. 33 § 1, 1971)