540 CMR, § 4.01
540 CMR 4.00 is adopted by the Registrar of Motor Vehicles pursuant to the authority of M.G.L. c. 90, § 31. 540 CMR 4.00 establishes Rules and Regulations for the Safety and Combined Safety and Emissions Inspections of all motor vehicles registered in the Commonwealth of Massachusetts under the authority of M.G.L. c. 90, § 7A. 540 CMR 4.00 also establishes regulations for the issuance of various inspection certificates pursuant to M.G.L. c. 90, § 7V(a), (b) and (c), and Regulations for the licensing of stations and inspectors pursuant to M.G.L. c. 90, § 7W. The failure of a motor vehicle to meet the requirements of the Safety and Combined Safety and Emissions Inspections will result in the suspension of the vehicle's certificate of registration pursuant of M.G.L. c. 90, § 20.
540 CMR 4.00 further and separately establishes the requirements, standards and specifications for Lateral Protective Devices, Convex Mirrors, Cross Over Mirror(s), and Backup Cameras for any Commonwealth Heavy Vehicle or Contractor Heavy Vehicle, as defined herein.
540 CMR, § 4.01