What safety regulations apply to commercial trucks and buses?

What the Law Says

The Motor Carrier Safety Act establishes the statutory foundation for federal regulation of commercial motor vehicles (CMVs), including trucks and buses engaged in interstate commerce. While 49 U.S.C. § 31101 itself is a definitions section, it anchors the broader regulatory framework administered by the Federal Motor Carrier Safety Administration (FMCSA).

The law defines key terms such as 'commercial motor vehicle' — meaning a vehicle used in commerce to transport passengers or property, with a gross vehicle weight rating (GVWR) of at least 10,001 pounds, or designed to transport 16 or more passengers (including the driver), or used to transport hazardous materials requiring placarding.

These definitions trigger applicability of comprehensive FMCSA safety regulations found in 49 CFR Parts 382–399, which govern driver qualifications, medical certification, hours of service, vehicle maintenance, inspection, and drug and alcohol testing.

Although § 31101 does not prescribe operational rules itself, it authorizes the Secretary of Transportation to issue regulations 'necessary to ensure the safe operation of commercial motor vehicles.'

Statutory Text

The term 'commercial motor vehicle' means a motor vehicle or combination of motor vehicles used in commerce to transport passengers or property if the vehicle—(A) has a gross vehicle weight rating or gross combination weight rating, or gross vehicle weight or gross combination weight, of 10,001 pounds or more; (B) is designed or used to transport more than 15 passengers, including the driver; or (C) is used in transporting material found by the Secretary of Transportation to be hazardous under section 5103 of this title and transported in a quantity requiring placarding under regulations prescribed by the Secretary under that section.

— 49 U.S.C. § 31101 — Definitions

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