Okla. Stat. tit. 47, § 47-11-309: Driving on roadways laned for traffic

Whenever any roadway has been divided into two or more clearly

marked lanes for traffic, the following requirements in addition to

all others consistent herewith shall apply:

1. A vehicle shall be driven as nearly as practicable entirely

within a single lane;

2. A vehicle shall not be moved from the lane until the driver

has first ascertained that the movement can be made with safety and

then given a signal, not less than the last one hundred (100) feet

traveled by the vehicle, of his or her intention to change lanes;

3. A two-way left-turn lane is a lane near the center of the

highway set aside for use by vehicles making left turns in both

directions from or into the roadway. Two-way left-turn lanes shall

be designated by distinctive roadway markings consisting of parallel

double yellow lines, interior line dashed and exterior line solid,

on each side of the lane. A vehicle shall not be driven in a

designated two-way left-turn lane except when preparing for or

making a left turn from or into a roadway. Vehicles turning left

from the roadway shall not be driven in the two-way left-turn lane

for more than two hundred (200) feet while preparing for and making

the turn. A vehicle turning left onto the roadway may utilize the

two-way left-turn lane as a staging area by stopping and waiting for

traffic proceeding in the same direction to clear before merging

into the adjacent lanes of travel. A left turn shall not be made

from any other lane where a two-way left-turn lane has been

designated. Provided, however, this section shall not prohibit

driving across a two-way left-turn lane when moving from a service

drive onto such marked roadway;

4. A vehicle shall not be driven in the left lane of a roadway

except when overtaking and passing another vehicle; provided,

however, this paragraph shall not prohibit driving in the left lane

when traffic conditions, flow or road configuration, such as the

potential of merging traffic, requires the use of the left lane to

maintain safe traffic conditions; provided further, this paragraph

shall not prohibit driving in the left lane of a roadway within the

city limits of a municipality or upon a county road as long as such

roadway is not part of the National System of Interstate and Defense

Highways or a turnpike; and

5. Official signs may be erected directing slow-moving traffic

to use a designated lane or designating those lanes to be used by

traffic moving in a particular direction regardless of the center of

the roadway, and drivers of vehicles shall obey the directions of

every such sign.

Any person convicted of violating any provision of this section

shall be punished as provided for in Section 17-101 of this title.