Okla. Stat. tit. 47, § 47-11-604: Turning movements and required signals

A. No person shall turn a vehicle at an intersection, a public

or private road, or a driveway, unless the vehicle is in proper

position upon the roadway as required in Section 11-601 of this

title, or move right or left upon a roadway unless and until such

movement can be made with reasonable safety. No person shall so

turn any vehicle without giving an appropriate signal as provided in

subsection B of this section, in the event any other traffic may be

affected by such movement.

B. A signal of intention to turn right or left as required by

law shall be given continuously during not less than the last one

hundred (100) feet traveled by the vehicle before turning.

C. No person shall stop or suddenly decrease the speed of a

vehicle without first giving an appropriate signal in the manner

provided in subsection B of this section to the driver of any

vehicle immediately to the rear when there is opportunity to give

such signal.

D. When any person is properly preparing for, attempting or

executing a left turn, as described in subsection A of this section,

no other person operating another vehicle immediately following the

turning vehicle shall pass or attempt to pass the turning vehicle to

the left. Such other person shall come to a complete stop if

necessary at a safe distance behind the person preparing for,

attempting or executing the turn or may proceed to the right of the

turning vehicle as provided by Section 11-304 of this title.