A. 
The traffic authority 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 under the traffic laws of the city to make effective the provisions of such laws.
B. 
Whenever the traffic laws require, for the effectiveness of any provisions thereof, that traffic control devices be installed to give notice to the public of the application of such laws, the traffic authority is authorized to install, or cause to be installed, the necessary devices subject to any limitations or restrictions set forth in the laws applicable thereto.
C. 
The traffic authority may also place and maintain, or cause to be placed and maintained, such additional traffic control devices as he may deem necessary to regulate traffic or to guide or warn traffic, but he shall make such determination only upon the basis of traffic engineering principles and traffic investigations, and in accordance with such standards, limitations, and rules as may be set forth in the traffic laws of the city or as may be determined by ordinance or resolution of the council.
(Prior code § 3-5.401)
No provision of the Vehicle Code of the state or of this title for which signs are required shall be enforced against an alleged violator unless appropriate signs are in place, and sufficiently legible to be seen by an ordinarily observant person, giving notice of such provisions of the traffic laws.
(Prior code § 3-5.402)
The driver of any vehicle shall obey the instructions of any official traffic control device applicable thereto placed in accordance with the traffic laws of the city unless otherwise directed by a police officer, subject to the exceptions granted the driver of an authorized emergency vehicle when responding to emergency calls.
(Prior code § 3-5.403)
The traffic authority is authorized to remove, relocate, or discontinue, or cause to have removed, relocated, or discontinued, the operation of any traffic control device not specifically required by state law or by this title whenever he shall determine in any particular case that the conditions which warranted or required the installation no longer exist or obtain.
(Prior code § 3-5.404)
The traffic authority shall determine the hours and days during which any traffic control device shall be in operation or effect except in those cases where such hours or days are specified in this title.
(Prior code § 3-5.405)
A. 
The traffic authority is directed to install and maintain, or cause to have installed and maintained, official traffic signals at those intersections and other places where traffic conditions are such as to require that the flow of traffic be alternately interrupted and released in order to prevent or relieve traffic congestion or to protect life or property from exceptional hazards.
B. 
The traffic authority shall ascertain and determine the locations where such signals are required by resort to field observation, traffic counts, and other traffic information as may be pertinent, and his determinations therefrom shall be made in accordance with those traffic engineering and safety standards and instructions set forth in the Planning Manual of Instructions, Part 8, "Traffic," issued by the Division of Highways of the Department of Public Works of the state.
C. 
Whenever the traffic authority installs and maintains, or causes to have installed and maintained, an official traffic signal at any intersection, he shall likewise erect and maintain, or cause to have erected and maintained, at such intersection street name signs visible to the principal flow of traffic unless such street name signs have previously been placed and are maintained at any such intersection.
(Prior code § 3-5.406)
The traffic authority is authorized to regulate, or cause to have regulated, the timing of traffic signals so as to permit the movement of traffic in an orderly and safe manner at speeds slightly at variance from the speed otherwise applicable within the district or at intersections, and may erect appropriate signs giving notice thereof.
(Prior code § 3-5.407)
The traffic authority is authorized to mark, or cause to be marked, center lines and lane lines upon the surface of the roadway to indicate the course to be traveled by vehicles and may place, or cause to be placed, signs temporarily designating lanes to be used by traffic moving in a particular direction, regardless of the center line of the highway.
(Prior code § 3-5.408)
The traffic authority is authorized to place and maintain, or cause to have placed and maintained, distinctive roadway markings as described in the Vehicle Code of the state on streets or parts of streets where the volume of traffic or the vertical or other curvature of the roadway renders it hazardous to drive on the left side of such markings or signs and markings. Such markings or signs and markings shall have the same effect as similar markings placed by the Department of Public Works of the state pursuant to provisions of the Vehicle Code of the state.
(Prior code § 3-5.409)