When a slow or a yield right of way sign is erected as provided in section 10.44.020 of this chapter at or near the entrance to any intersection, every driver of a vehicle shall slow such vehicle to a speed of not more than ten (10) miles per hour by the time the vehicle is even with the sign, except when directed to proceed by a police officer or a traffic control signal. The driver may then proceed cautiously and shall yield the right of way to vehicles not obliged to stop or to slow down, which have entered the intersection from the other street or which are approaching so closely thereon as to constitute an immediate hazard. (Prior code §18-56)