[CC 1987 §620.010(1)]
A. 
The City Traffic Engineer shall place and maintain traffic control signs, signals and devices when and as required under the traffic ordinances of the City to make effective the provisions of said ordinances and may place and maintain such additional traffic control devices as he/she may deem necessary to regulate traffic under the traffic ordinances of the City or under State law or to guide or warn traffic.
B. 
The State Highway and Transportation Commission of Missouri shall have exclusive authority to place and maintain traffic control signs, signals and devices on all highways maintained by the State Highway and Transportation Commission. The State Highway and Transportation Commission is given express authority to delegate to the District Engineer any power or authority vested in the State Highway and Transportation Commission by this Section
All traffic control signs, signals and devices shall conform to the manual and specifications approved by the State Highways and Transportation Commission or resolution adopted by the Board of Aldermen of the City. All signs or signals required hereunder for a particular purpose 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 this Title shall be official traffic control devices.
The driver of any vehicle shall obey the instructions of any official traffic control device applicable thereto placed in accordance with the provisions of this Title, unless otherwise directed by a traffic or Police Officer, subject to the exceptions granted the driver of an authorized emergency vehicle in this Title.
No provision of this Title for which official traffic control devices are required shall be enforced against an alleged violator if at the time and place of the alleged violation an official device is not in proper position and sufficiently legible to be seen by an ordinarily observant person. Whenever a particular Section does not state that official traffic control devices are required, such Section shall be effective even though no devices are erected or in place.
A. 
Whenever official traffic control devices are placed in position approximately conforming to the requirements of this Title, such devices shall be presumed to have been so placed by the official act or direction of lawful authority, unless the contrary shall be established by competent evidence.
B. 
Any official traffic control device placed pursuant to the provisions of this Title and purporting to conform to the lawful requirements pertaining to such devices shall be presumed to comply with the requirements of this Title, unless the contrary shall be established by competent evidence.
A. 
Whenever traffic is controlled by traffic control signals exhibiting different colored lights or colored lighted arrows, successively one (1) at a time or in combination, only the colors green, red and yellow shall be used except for special pedestrian signals carrying a word legend, and said lights shall indicate and apply to drivers of vehicles and pedestrians as follows:
1. 
Green indication.
a. 
Vehicular traffic facing a circular green signal may proceed straight through or turn right or left unless a sign at such place prohibits either such turn. But vehicular traffic, including vehicles turning right or left, shall yield the right-of-way to other vehicles and to pedestrians lawfully within the intersection or an adjacent crosswalk at the time such signal is exhibited.
b. 
Vehicular traffic facing a green arrow signal, shown alone or in combination with another indication, may cautiously enter the intersection only to make the movement indicated by such arrow, or such other movement as is permitted by other indications shown at the same time. Such vehicular traffic shall yield the right-of-way to pedestrians lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
c. 
Unless otherwise directed by a pedestrian control signal as provided in Section 315.070, pedestrians facing any green signal, except when the sole green signal is a turn arrow, may proceed across the roadway within any marked or unmarked crosswalk.
2. 
Steady yellow indication.
a. 
Vehicular traffic facing a steady yellow signal is thereby warned that the related green movement is being terminated or that a red indication will be exhibited immediately thereafter when vehicular traffic shall not enter the intersection.
b. 
Pedestrians facing a steady yellow signal, unless otherwise directed by a pedestrian control signal as provided in Section 315.070, are thereby advised that there is insufficient time to cross the roadway before a red indication is shown and no pedestrian shall then start to cross the roadway.
3. 
Steady red indication.
a. 
Vehicular traffic facing a steady red signal alone shall stop before entering the crosswalk on the near side of the intersection or, if none, then before entering the intersection and shall remain standing until a green indication is shown except as provided in paragraph (b) of this Subsection.
b. 
The driver of a vehicle which is stopped as close as practicable at the entrance to the crosswalk on the near side of the intersection or, if none, then at the entrance to the intersection in obedience to a red signal may cautiously enter the intersection to make a right turn but shall yield the right-of-way to pedestrians and other traffic proceeding as directed by the signal at the intersection, except that the State Highways and Transportation Commission with reference to an intersection involving a State highway, and local authorities with reference to an intersection involving other highways under their jurisdiction, may prohibit any such right turn against a red signal at any intersection where safety conditions so require, said prohibition shall be effective when a sign is erected at such intersection giving notice thereof.
c. 
Unless otherwise directed by a pedestrian control signal as provided in Section 315.070, pedestrians facing a steady red signal alone shall not enter the roadway.
4. 
In the event an official traffic control signal is erected and maintained at a place other than an intersection, the provisions of this Section shall be applicable except as to those provisions which by their nature can have no application. Any stop required shall be made at a sign or marking on the pavement indicating where the stop shall be made, but in the absence of any such sign or marking, the stop shall be made at the signal.
A. 
Whenever special pedestrian control signals exhibiting the words "Walk" or "Don't Walk", or appropriate symbols, are in place, such signals shall indicate as follows:
1. 
"WALK": Pedestrians facing such signal may proceed across the roadway in the direction of the signal and shall be given the right-of-way by the drivers of all vehicles.
2. 
"WAIT" or "DON'T WALK": No pedestrian shall start to cross the roadway in the direction of such signal, but any pedestrian who has partially completed his/her crossing on the walk signal shall proceed to a sidewalk or safety zone while the wait signal is showing.
A. 
Whenever an illuminated flashing red or yellow signal is used in a traffic sign or signal, it shall require obedience by vehicular traffic as follows:
1. 
Flashing red (stop signal). When a red lens is illuminated with rapid intermittent flashes, drivers of vehicles shall stop before entering the nearest crosswalk at an intersection or at a limit line when marked or, if none, then before entering the intersection, and the right to proceed shall be subject to the rules applicable after making a stop at a stop sign.
2. 
Flashing yellow (caution signal). When a yellow lens is illuminated with rapid intermittent flashes, drivers of vehicles may proceed through the intersection or past such signal only with caution.
B. 
This Section shall not apply at railroad grade crossings. Conduct of drivers of vehicles approaching railroad grade crossings shall be governed by the rules as set forth in Section 335.090 of this Title.
When lane direction control signals are placed over the individual lanes of a street or highway, vehicular traffic may travel in any lane over which a green signal is shown but shall not enter or travel in any lane over which a red signal is shown.
No person shall place, maintain or display upon or in view of any highway an unauthorized sign, signal, marking or device which purports to be or is an imitation of or resembles an official traffic control device or railroad sign or signal, or which attempts to direct the movement of traffic, or which hides from view or interferes with the effectiveness of any official traffic control device or any railroad sign or signal.
No person shall without lawful authority attempt to or in fact alter, deface, injure, knock down or remove any official traffic control device or any railroad sign or signal or any inscription, shield or insignia thereon, or any other part thereof.
The City Traffic Engineer shall have authority to declare any street or part thereof a play street and to place appropriate signs or devices in the roadway indicating and helping to protect the same.
Whenever authorized signs are erected indicating any street or part thereof as a play street, no person shall drive a vehicle upon any such street or portion thereof except drivers of vehicles having business or whose residences are within such closed area, and then any said driver shall exercise the greatest care in driving upon any such street or portion thereof.
A. 
The City Traffic Engineer is hereby authorized:
1. 
To designate and maintain, by appropriate devices, marks or lines upon the surface of the roadway, crosswalks at intersections where in his/her opinion there is particular danger to pedestrians crossing the roadway, and at such other places as he/she may deem necessary.
2. 
To establish safety zones of such kind and character and at such places as he/she may deem necessary for the protection of pedestrians.
A. 
The City Traffic Engineer is hereby authorized to mark traffic lanes upon the roadway of any street or highway where a regular alignment of traffic is necessary.
B. 
Where such traffic lanes have been marked, it shall be unlawful for the operator of any vehicle to fail or refuse to keep such vehicle within the boundaries of any such lane except when lawfully passing another vehicle or preparatory to making a lawful turning movement.