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Everything You Need to Know About Semitrailer Length Laws by State

To the average person, semitrailers are highway behemoths that you wouldn’t want to find yourself driving next to.

Everything You Need to Know About SemitrailerLenght Laws by State

Tags: Laws and Regulations

To the average person, semitrailers are highway behemoths that you wouldn’t want to find yourself driving next to. To kids, they are a source of awe and entertainment on long drives. To all of us though, commercial trailers are the arteries and veins that keep the country moving. They are the conduit through which your favorite cereal ends up on the supermarket shelf, your Amazon delivery reaches you on time, and gas is available at your local gas station.

There’s no question about it—semitrailers are imposing. You may be familiar to some degree with weight restrictions, but less well known are trailer length restrictions. There are semitrailer length laws by state as well as at the federal level. Before we get into that, let’s take a quick look at the typical truck configurations in America.

Most Common Commercial Truck Configurations

There are many ways commercial trucks can be classified and defined. The FMCSA defines commercial trucks as road vehicles with a gross vehicle weight of more than 10,000 pounds designed to carry freight. The FHWA categorizes freight-carrying vehicles into nine classes based on the number of axles, the number of units, and the type of unit combinations. Nevertheless, most commercial truck configurations in America fall into three main categories.

1. Combination Trucks

More widely known as the 18-wheeler, the five-axle tractor semitrailer is the most recognizable commercial truck in the USA. The tractor (i.e. power unit) is either a sleeper cab or a day cab. Sleeper cabs have a sleeping berth or small living area in the tractor. They are typically used for long-haul operations. Day cabs have a shorter wheelbase and are used for short haul operations, such as delivery and pickup. The freight-carrying unit of a tractor semitrailer vehicle usually varies between 40 and 53 feet in length; although, some states allow semitrailer lengths of up to 59′ 6″.

2. Straight or Single-Unit Trucks

A straight or single-unit truck is a commercial freight road vehicle where the vehicle chassis and power unit are permanently attached. Straight trucks are most commonly used for beverage delivery, parcel delivery, concrete mixing, construction debris dumping, trash compacting, and snow plowing.

3. Longer Combination Vehicles (LCVs)

LCVs are a type of combination truck that only operate in states where freight trucks exceeding 80,000 pounds are permitted. They are three- or four-unit combinations that include at least one full trailer (48 feet or less) or three short trailers.

Federal Semitrailer Length Provisions

In 1982, the US Congress passed the Surface Transportation Assistance Act (STAA) that included provisions relating to the length of truck tractor-semitrailer and truck tractor-semitrailer-trailer combinations on National Network (NN) highways or in transit between NN highways and service locations or terminals. These provisions included the following:

  • 48 feet is the minimum length limitation a state could impose on a semitrailer operating as part of a truck tractor-semitrailer combination.
  • 28 feet is the minimum length limitation a state could impose on a trailer or semitrailer operating as part of a truck tractor-semitrailer-trailer combination.
  • A state shall not impose a limitation on the overall length of a commercial vehicle operating as part of a truck tractor-semitrailer-trailer or truck tractor-semitrailer combination.
  • A state shall not prohibit truck tractor-semitrailer commercial vehicles.

Semitrailer Length Laws by State

Some states were granted exceptions to the Federal length standards and were thus allowed to enforce higher limits before the STAA standard. These exceptions are referred to as ‘grandfathered rights;’ whereas federal laws require that states cannot legislate trailer length to be under 53 feet on the Interstate and access roads, states are free to allow trailers that are less than 53 feet on roads that aren’t funded by the federal government.

The following table is a summary of the semitrailer length laws by state:

State

Maximum Trailer Length (in feet)

Maximum Trailer Length (in meters)

Sub-State Measures and Additional Notes

Alabama

57′ 0″

17.37

53′ 6″ maximum on roads that are less than 12′

Alaska

53′ 0″

16.15

1) 48′ 0″ maximum on non-designated highways 2) Trailer must have kingpin-to-center distance of 41′ or less if it’s 48′ or more

Arizona

57′ 6″

17.53

53′ 0″ maximum on other (non-Interstate) highways

Arkansas

53′ 6″

16.31

Permit may be available for trailers up to 59′ 6″ long

California

48′ 0″

14.63

1) 53’ maximum for semitrailers with a kingpin-to-center distance of 40’ or less 2) No trailer length limit on California Black Routes

Colorado

57′ 4″

17.48

 

Connecticut

53′ 0″

16.15

48′ 0″ maximum on non-designated State routes

Delaware

53′ 0″

16.15

 

Florida

57′ 0″

17.37

Trailer must have kingpin-to-center distance of 41′ or less if the trailer is longer than 48′

Georgia

48′ 0″

14.63

 

Hawaii

48′ 0″

14.63

 

Idaho

53′ 0″

16.15

48′ 0″ maximum on designated secondary highways (non-NN)

Illinois

53′ 0″

16.15

 

Indiana

48′ 0″

14.63

53’ maximum permitted if 1) kingpin-to-rearmost axle distance is 40′ 6″ or less 2) kingpin-to-center distance is 45′ 6″ or less

Iowa

53′ 0″

16.15

 

Kansas

57′ 6″

17.53

 

Kentucky

53′ 0″

16.15

 

Louisiana

59′ 6″

18.14

 

Maine

53′ 0″

16.15

48′ 0″ maximum on non-53′ network

Maryland

53′ 0″

16.15

1) 48′ 0″ maximum on non-designated highways 2) Kingpin-to-center distance should not exceed 41′ for trailers longer than 48′

Massachusetts

53′ 0″

16.15

 

Michigan

53′ 0″

16.15

48′ maximum on non-designated highways

Minnesota

53′ 0″

16.15

 

Mississippi

53′ 0″

16.15

 

Missouri

53′ 0″

16.15

 

Montana

53′ 0″

16.15

 

Nebraska

53′ 0″

16.15

 

Nevada

53′ 0″

16.15

 

New Hampshire

53′ 0″

16.15

48′ 0″ maximum on non-designated highways

New Jersey

53′ 0″

14.63

48′ 0″ maximum on State roads other than the 102″ network

New Mexico

57′ 6″

17.53

 

New York

53′ 0″

16.15

1) 48′ 0″ maximum on non-qualifying highways 2) Trailers exceeding 48′ must have kingpin-to-rear axle center setting of 43′ or less

North Carolina

53′ 0″

16.15

48′ 0″ maximum on non-designated highways

North Dakota

53′ 0″

16.15

 

Ohio

53′ 0″

16.15

 

Oklahoma

59′ 6″

18.14

53′ 0″ maximum on State roads

Oregon

53′ 0″

16.15

 

Pennsylvania

53′ 0″

16.15

Kingpin-to-rear axle center must not exceed 41′

Rhode Island

53′ 0″

16.15

1) 48′ 0″ maximum on non-Interstate routes 2) Kingpin-to-rear axle center must not exceed 41′

South Carolina

53′ 0″

16.15

Kingpin-to-rear axle center must not exceed 41′

South Dakota

53′ 0″

16.15

 

Tennessee

53′ 0″

16.15

Kingpin-to-end of trailer or load must not exceed 50′

Texas

59′ 0″

17.98

 

Utah

53′ 0″

16.15

1) Permit available for trailers up to 57′ 0″ long 2) 48′ 0″ maximum on non-designated roads

Vermont

53′ 0″

16.15

1) 48′ 0″ maximum on non-designated highways 2) For 53′ 0″ trailer, kingpin-to-rear axle center setting should not exceed 43′

Virginia

48′ 0″

14.63

Up to 53′ 0″ trailer allowed as long as kingpin-to-rear tandem center does not exceed 41′

Washington

53′ 0″

16.15

Permit available for longer trailers up to 56′ 0″

West Virginia

53′ 0″

16.15

48′ 0″ maximum on non-designated highways

Wisconsin

53′ 0″

16.15

48′ 0″ maximum on non-designated highways

Wyoming

53′ 0″

16.15

48′ 0″ maximum on non-designated highways

Table via U.S Department of Transportation

Exceptions to Semitrailer Length Laws by State

The STAA rules only apply to truck-tractor semitrailer and truck-tractor semitrailer-trailer combinations. Certain specialized commercial motor vehicles (CMV) are subject to a different set of length rules. Notable specialized vehicles include automobile transporters, boat transporters, and truck-tractor semitrailer combinations. The length requirements of these vehicles are as follows.

1. Automobile Transporters

  • 65 feet is the minimum length limitation a state shall impose on the overall length of traditional automobile transporters (those ones where the 5th wheel is positioned on the tractor frame above the rear axle) including lowboys.
  • 75 feet is the minimum overall length limitation a state shall impose on stinger-steered automobile transporters.
  • 97 feet is the overall length limit states can impose on drive-away saddle-mount vehicle transporter combinations.

2. Boat Transporters

  • 65 feet is the minimum overall length limitation a state can impose on traditional boat transporters including lowboys.
  • 75 feet is the minimum overall length limitation a state can impose on stinger-steered boat transporters.
  • 65 feet is the minimum overall length limitation a state can impose on a truck-trailer boat transporter.

3. Truck-Tractor Semitrailer

  • 28 feet is the minimum semitrailer length limitation a state can impose on truck-tractor semitrailer vehicle combinations.
  • If each semitrailer is 28 feet long or more, a state shall not impose an overall length limitation.

Note that length provisions for automobile transporters and boat transporters exclude the front and rear overhang. No state shall impose a rear overhang of under 4 feet or a front overhang of under 3 feet.

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