Okla. Stat. tit. 47, § 47-11-304: When overtaking on the right is permitted

(a) The driver of a vehicle may overtake and pass upon the right

of another vehicle only under the following conditions:

1. When the vehicle overtaken is making or about to make a left

turn;

2. Upon a street or highway with unobstructed pavement not

occupied by parked vehicles of sufficient width for two or more

lines of moving vehicles in each direction;

3. Upon a one-way street, or upon any roadway on which traffic

is restricted to one direction of movement, where the roadway is

free from obstructions and of sufficient width for two or more lines

of moving vehicles.

(b) The driver of a vehicle may overtake and pass another

vehicle upon the right only under conditions permitting such

movement in safety. In no event shall such movement be made by

driving off the pavement or main traveled portion of the roadway.