Okla. Stat. tit. 47, § 47-1-158: Roadway and shoulder

(a) Roadway. That portion of a highway improved, designed or

ordinarily used for vehicular travel, exclusive of the shoulder. In

the event a highway includes two or more separate roadways the term

"roadway" as used herein shall refer to any such roadway separately

but not to all such roadways collectively.

(b) Shoulder. The portion of the roadway contiguous with the

traveled way for accommodation of stopped vehicles, for emergency

use, and for lateral support of base and surface courses.