07/15/2026
What is a Boat or Automobile Transporter?
Title 23 CFR Chapter 1 Subchapter G Part 658 states
Automobile Transporters : Any vehicle combination designed and used specifically for the transport of assembled highway vehicles including truck camper units.
Boat Transporters : Any vehicle combination designed and used to specifically transport assembled boat and boat hulls. Boats may be partially disassembled to facilitate transporting.
The Federal Register further defines a Boat or Automobile Transporter and also states legal limits
If a vehicle is classified as an automobile transporter, no State shall impose an overall length limitation of less than 65 feet on traditional automobile transporters, including “low boys,” or less than 80 feet on stinger-steered automobile transporters. 49 U.S.C. 31111(b)(1)(G). All length provisions regarding automobile transporters are exclusive of front and rear cargo overhang. For traditional automobile transporters, no State shall impose a front overhang limitation of less than 3 feet or a rear overhang limitation of less than 4 feet. 23 CFR 658.13(e)(1)(ii). For stinger-steered automobile transporters, no State shall impose a front overhang limitation of less than 4 feet or a rear overhang limitation of less than 6 feet. 49 U.S.C. 31111(b)(1)(G).
Other truck tractor-semitrailer combinations (not specifically defined as automobile transporters) are subject to the length provisions of 23 CFR 658.13(c). Under this regulatory provision, States determine the maximum length limits for semitrailers operating in a truck tractor-semitrailer combination; but no State shall prohibit the use of trailers or semitrailers of such dimensions as those that were in actual and lawful use in such State on December 1, 1982, as set out in appendix B to 23 CFR 658.
It is a longstanding FHWA policy position, established through guidance, that to qualify as an automobile transporter as defined in 49 U.S.C. 31111(a)(1) and be treated as specialized equipment as described in 23 CFR 658.13(e)(1)(i), both traditional and stinger-steered automobile transporter combinations must be capable of carrying cargo on the power unit/tractor. Because a truck-tractor in high-mount, truck-tractor-semitrailer combination is not capable of carrying vehicles on the power unit, FHWA's current policy interpretation is that such a vehicle combination may not be considered an automobile transporter subject to the length allowances in 23 CFR 658.13(e)(1)(ii).
