All traffic-control signs, signals and devices installed or erected in the city shall conform to the manual and specifications approved by the state transportation commission. All signs and signals required under this article shall, so far as practicable, be uniform as to type and location throughout the city. All traffic-control devices so erected and not inconsistent with the provisions of state law or this article shall be official traffic-control devices.
(1999 Code, sec. 70.20)
(a) 
The city council shall by ordinance direct that the chief of police or director of public works shall have the duty of erecting or installing upon, over, along, or beside any highway, street or alley signs, signals and markings, or causing the same to be erected, installed or placed, in accordance with this article and consistent with the manual adopted hereby. The traffic-control devices shall be installed immediately, or as soon as such specific device, sign or signal can be procured.
(b) 
Whenever the chief of police or director of public works has erected and installed any official traffic-control device, signal or sign at any location in the city, or has caused the same to be done under his direction, in obedience to this article, the manual adopted hereby or another ordinance directing the erection of such device, signal or sign, he shall thereafter file a report with the city secretary in writing and signed officially by the chief of police or director of public works, stating the type of traffic-control device, sign or signal, and when and where the same was erected or installed. The city secretary shall file and maintain such report of the chief of police or director of public works among the official papers of the office of the city secretary.
(1999 Code, sec. 70.21)
The chief of police shall, with the approval of the city council, place and maintain traffic-control signs, signals, and devices when required under the provisions of this chapter and any other traffic ordinance of this city to make effective such provisions, and in case of emergency may place and maintain such additional traffic-control devices as he may deem necessary to regulate traffic under the traffic ordinances of this city or under state law, or to guide or warn traffic.
(1999 Code, sec. 70.23)
It shall be the duty of the chief of police to place and maintain a stop sign on each and every street intersecting a through street, unless traffic at any such intersection is controlled at all times by traffic-control signals; provided, however, that at the intersection of two such through streets or at the intersection of a through and a heavy traffic street not designated, stop signs shall be erected at the approaches of either of the streets as may be determined by the chief of police upon the basis of an engineering and traffic study and upon authority of the council.
(1999 Code, sec. 70.24(a))
All traffic-control signs, signals, devices, and markings placed or erected prior to the adoption of this code and in use for the purpose of regulating, warning or guiding traffic are hereby affirmed, ratified and declared to be official traffic-control devices, provided such traffic-control devices are not inconsistent with the provisions of this chapter or state law.
(1999 Code, sec. 70.26)
In any prosecution for a violation of this chapter or any traffic ordinance of the city, evidence that any traffic-control device, sign, signal or marking was actually in place on any street shall constitute prima facie evidence that the same was installed by the chief of police or director of public works pursuant to the authority of this article and of the ordinance directing the installation of such device, signal or marking.
(1999 Code, sec. 70.33)