60-6,134. Overtaking and passing upon the right; when permitted.
(1) The driver of a vehicle may overtake and pass on the right of another vehicle only under the following conditions:
(a) When the vehicle to be overtaken is making or about to make a left turn;
(b) Upon a two-way street or highway with an unobstructed roadway, not occupied by parked vehicles, of sufficient width for two or more lanes of moving vehicles going in the same direction when the passing vehicle is traveling in one of such lanes; or
(c) Upon a one-way street, or upon any roadway on which traffic is restricted to one direction of movement, when the roadway is free from obstructions and of sufficient width for two or more lanes of moving vehicles.
(2) In no event shall the driver of a vehicle overtake and pass another vehicle upon the right unless such movement may be made safely upon the roadway.
Source