Md. Code, Transp. § 11-172
Current with changes from the 2024 legislative session from Chs. 2 through 1049, effective on or before 6/1/2024
"Truck tractor" means the noncargo carrying power unit that operates in combination with a semitrailer or trailer, except that a truck tractor and semitrailer engaged in the transportation of automobiles or boats may transport motor vehicles or boats on part of the power unit.
Md. Code, TR § 11-172