According to Title 11 (Department of Transportation) of the Code of Maryland Regulations (COMAR), the MDOT only has authority to regulate the weight of motor vehicles that are legally defined as commercial motor vehicles (CMVs) by Federal Motor Carrier Safety Regulations (FMCSR). FMCSR defines two classes of CMVs: regular CMVs that operate in commerce (mainly tractor trailers) and smaller CMVs (mainly recreational vehicles, passenger buses, rental trucks moving private property and multipurpose vehicles).
Regular CMVs must have a gross vehicle weight rating (GVWR) of at least 26,001 lb. If the regular CMV is being operated in combination with a trailer, the gross combination weight rating (GCWR) must exceed 26,001 lb. with the GVWR of the trailer exceeding 10,001 lb. Smaller CMVs must have either a GVWR, or a GCWR, of at least 10,001 lb.
The manufacturer's GVWR is usually found on a sticker located on the edge of the driver's door or the door frame of the CMV. The GCWR is usually located on the door frame of the trailer. Any driver with a CMV, or a CMV/trailer combination, that falls within the regulated GVWR/GCWR ranges must register such with the SHA. The driver must also obtain a commercial driver's license (CDL) from the MVA.