§ 20-156 ONE-WAY STREETS AND ALLEYS.
   Upon those streets and parts of streets and in those alleys and parts of alleys so designated as one- way streets and alleys, vehicular traffic shall move only in the direction indicated when signs indicating the direction of traffic are erected and maintained at every intersection where movement in the opposite direction is prohibited.
(47 O.S. § 11-308(b)) (`90 Code, § 20-59)