Carriers operating commercial motor vehicles as defined in 390.5T must comply with parts and accessories regulations in 49 CFR 393. This section outlines some of the most common standard equipment that every commercial motor vehicle (CMV) must have. Additional equipment or accessories are allowed if those items do not decrease operational safety. See Marking of Self-Propelled CMVs and Intermodal Equipment for information about what business information must be displayed on carrier equipment.