§ 20-64  TRAFFIC-CONTROL SIGNAL LEGEND.
   Whenever traffic is controlled by traffic-control signals exhibiting the words “Go,” “Caution” or “Stop” or exhibiting different colored lights successively one at a time, or with arrows, the following colors only shall be used, and the terms and lights shall indicate and apply to drivers of vehicles and pedestrians as follows:
   (A)   Green alone or “Go.”
      (1)   Vehicular traffic facing the signal fray proceed straight through or turn right or left unless a sign or barricade at a place that prohibits either 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 the signal is exhibited.
      (2)   Pedestrians facing a signal may proceed across the roadway within any marked or unmarked crosswalk.
   (B)   Steady yellow alone.
      (1)   Vehicular traffic facing the signal is thereby warned that the red or “Stop” signal will be exhibited immediately thereafter, and the vehicular traffic shall not enter or be crossing the intersection when the red or “Stop” signal is exhibited.
      (2)   Pedestrians facing the signal are thereby advised that there is insufficient time to cross the roadway, and any pedestrian then starting to cross shall yield the right-of-way to all vehicles.
   (C)   Steady red alone or “Stop.”
      (1)   Whenever a traffic control signal on a street or boulevard in the city exhibits the word “Stop,” in red, then all vehicular traffic facing the signal shall stop before entering the crosswalk on the nearest side of the intersection, or if none, then before entering the intersection and shall remain standing until “Green” or “Go” is shown alone, or, while the signal is still red, vehicular traffic may turn right from the appropriate by an appropriate sign, which reads, “No right turn” or “No turn.”  The vehicular traffic shall yield the right-of-way to-pedestrians lawfully within an adjacent crosswalk and to other traffic lawfully using the intersection.
      (2)   With any crossing or intersection in the corporate limits of the city, a right turn on red is not permitted for any reason or if no turn at an intersection is permitted at any time, then there must be erected a clear concise sign informing drivers that the turns are prohibited, the signs shall be designed by the Highway Department and designed to be used for this purpose.
   (D)   Steady red with green arrow.
      (1)   Vehicular traffic facing the signal may cautiously enter the intersection only to make the movement indicated by the arrow, but shall yield the right-of-way to pedestrians lawfully within the crosswalk and to other traffic lawfully using the intersection.
      (2)   No pedestrian facing the signal shall enter the roadway until the green or “Go” is shown alone or until authorized so to do by pedestrian “Walk” signal.
   (E)   Erection and maintenance.  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.  In the absence of any sign or marking, the stop shall be made at the signal.
(47 O.S. § 11-202)  (`90 Code, § 20-24)