Any vehicular portable structure built on a chassis which is not propelled by its own power but is towed by another vehicle and is used as a temporary dwelling for travel, recreational or vacational use. A travel trailer shall have a body width not exceeding eight (8) feet in travel mode and an overall length not exceeding forty (40) feet, including the hitch or coupling.
Okla. Stat. tit. 47, § 1-181.1