§47-11-307.

§47-11-307.
   
   (a) The Oklahoma Department of Highways or other designated
   authorities are hereby authorized to determine those portions of any
   highway where overtaking and passing or driving to the left of the
   roadway would be especially hazardous and may by appropriate signs or
   markings on the roadway indicate the beginning and end of such zones
   and when such signs or markings are in place and clearly visible to an
   ordinarily observant person every driver of a vehicle shall obey the
   directions thereof.
   
   (b) Where signs or markings are in place to define a no-passing zone
   as set forth in paragraph (a) no driver shall at any time drive to the
   left side of the roadway within such no-passing zone or on the left
   side of any pavement striping designed to mark such no-passing zone
   throughout its length.