The NHVC determines the maximum number of trailers a heavy vehicle is allowed to tow.
If you wish to increase the amount of trailers, the category must be changed before any travel or you will be fined for using more than the towing vehicle is registered to haul.
You can change the category by completing the form (PDF) and sending it via fax, email or in person or using your DoTDirect account.
Vehicles with the body type code MULTI cannot be updated through DoTDirect.
