Maryland Transportation Section 13-918
§ 13-918.
  (a)   If a Class E (truck) vehicle is operated in combination with a nonfreight trailer or semitrailer under § 13-927(b)(1) of this subtitle, the Class E (truck) vehicle shall be registered for only the gross vehicle weight of the Class E (truck) vehicle and not the gross combination weight of the Class E (truck) vehicle and nonfreight trailer or semitrailer.
  (b)   If a Class E (truck) vehicle is operated in combination with a freight trailer or semitrailer, under § 13-927(c)(1) of this subtitle, the Class E (truck) vehicle shall be registered for the gross combination weight, which includes the gross weight of the Class E (truck) vehicle, and the freight trailer or semitrailer with which it is in combination.