The Oklahoma Statute that authorizes towing of vehicles from private property is TITLE 47 § 954A.  This statute says, in part:

In addition to any procedure provided by local ordinance, whenever the owner or legal possessor of real property or an authorized agent has reasonable cause to believe that a vehicle has been abandoned thereon, said vehicle having been on said property for a minimum of forty-eight (48) hours, or whenever a vehicle is left upon said real property without express or implied permission, such vehicle may be removed as provided in this section.

Once a car has been abandoned for 48 hours on any real property, the owner, lawful possessor, or their authorized agent can call any AA licensed wrecker service in that county and cause the vehicle to be removed and impounded.