Length requirements

Scope

Length requirements apply to:

• Truck tractor-semitrailer combinations
• Truck tractor-semitrailer-trailer combinations
• Buses
• Specialized equipment

Regulatory citations

• 23 CFR 658.13 — Length

Key definitions

• Commercial motor vehicle (CMV): A motor vehicle designed or regularly used to carry freight, merchandise, or more than ten passengers, whether loaded or empty, including buses, but not including vehicles used for vanpools, or recreational vehicles operating under their own power.

• Interstate system: The National System of Interstate and Defense Highways described in sections 103(e) and 139(a) of Title 23, U.S.C. For the purpose of this regulation this system includes toll roads designated as Interstate.

• Tractor or truck tractor: The non-cargo carrying power unit that operates in combination with a semitrailer or trailer (exceptions apply).

Summary of requirements

The Surface Transportation Assistance Act of 1982 (STAA)-imposed federal length limits for the Interstate Highway System and other designated state highways are as follows:

• No state shall impose:
  • A length limitation of less than 48 feet on a semitrailer operating in a truck tractor-semitrailer combination,
  • A length limitation of less than 28 feet on any semitrailer or trailer operating in a truck tractor-semitrailer-trailer combination,
  • An overall length limitation on commercial vehicles operating in truck tractor-semitrailer or truck tractor-semitrailer-trailer combinations, or
  • A limit of less than 45 feet on the length of any bus; and
• No state shall prohibit:
  • Commercial motor vehicles operating in truck tractor-semitrailer-trailer combinations,
  • The operation of semitrailers or trailers which are 28 ½ feet long when operating in a truck tractor-semitrailer-trailer combination if such a trailer or semitrailer was in actual and lawful operation on December 1, 1982, and the combination has an overall length not exceeding 65 feet,
  • The use of trailers or semitrailers of such dimensions as those that were in actual and lawful use in the state on December 1, 1982, or
  • If semi-trailer length was determined on that date by the distance from the kingpin to rearmost axle, or end of semitrailer, the operation of any semitrailer that complies with that limitation must be allowed.