Chapter 11-11 Special Vehicle Configurations Special Vehicle Configurations Due to the specialized nature of some vehicle, registration requirement are not uniform from state to state. When registering any of the following vehicles, special consideration must be given to the specific registration requirements of each state in which you desire apportionment. Do not hesitate to contact the IRP processing Center for assistance. Mobile Home Toter Massachusetts will assess the registration fee on the combined gross weight of the power unit only. The gross weight is defined as the unladen weight of the vehicle and that portion of the weight of the unit being towed resting on the rear axles of the power unit. Road Service Vehicle Massachusetts will assess the registration fee on the gross weight of the fully equipped road service vehicle. The vehicle that is being towed must be either property registered or bear a "repair" plate. Refer to the Wrecker and Tow Truck Information for a detailed listing of registration requirements for this type of vehicle in other jurisdictions. NOTE: In Massachusetts, both of the above body style configurations utilize the roadtractor (RT) designation. 11:24