Md. Code, Transportation § 11–170

(a) “Travel trailer” means a vehicle that is:

(1) (i) Mounted on wheels;

(ii) Of such a size and weight as not to require any special highway movement permit when towed by a motor vehicle;

(iii) Designed and constructed primarily to provide temporary living quarters for recreational, camping, or travel use; and

(iv) No longer than 40 feet; or

(2) A park model recreational vehicle.

(b) “Travel trailer” includes a fifth wheel travel trailer.