Md. Code Regs. 11.22.02.01
The standards, requirements, and procedures set forth in this chapter are applicable to equipment originally installed by the manufacturer or required by federal or State law or regulation on any vehicle registered as a Class E (truck) vehicle with a registered gross vehicle weight or gross combination weight greater than 10,000 pounds, or a Class F (tractor) vehicle under the provisions of Transportation Article, Title 13, Annotated Code of Maryland, or any single unit truck with a gross vehicle weight greater than 10,000 pounds or a gross combination vehicle weight greater than 10,000 pounds when operated in combination with a freight trailer or semitrailer or any truck tractor owned by this State or any political subdivision of this State. Compliance with these minimum requirements may not be sufficient for the equipment to remain in compliance with the minimum time or mileage requirements of COMAR 11.22.01.03AA and B. Therefore, more frequent maintenance, service, and repair as considered necessary by the owner is permitted and recommended.
Md. Code Regs. 11.22.02.01