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South Carolina Axle Weight Limits

Oversize.io Axle Weight Calculator

Maximum Legal Weight Allowed

National weight standards apply to commercial vehicle operations on the Interstate Highway System, an approximately 40,000-mile system of limited access, divided highways that spans the nation. Off the Interstate Highway System, states may set their own commercial vehicle weight standards.

Federal commercial vehicle maximum standards on the Interstate Highway System are:

Single Axle:

20,000 pounds

Tandem Axle:

34,000 pounds

Gross Vehicle Weight:

80,000 pounds

Bridge Formula Weights

The bridge formula was introduced in 1975 to reduce the risk of damage to highway bridges by requiring more axles, or a longer wheelbase, to compensate for increased vehicle weight. The formula may require a lower gross vehicle weight, depending on the number and spacing of the axles in the combination vehicle.

Maximum Permit Weight Allowed

Gross Weights

  • Two axle single unit vehicle 40,000 pounds
  • Three axle single unit vehicle 50,000 pounds
  • Four or more axle single unit vehicle 65,000 pounds
  • Combination of vehicles with three axles 55,000 pounds
  • Combination of vehicles with four axles 70,000 pounds
  • Combination of vehicles with five axles 90,000 pounds
  • Combination of vehicles with six axles 110,000 pounds
  • Combination of vehicles with seven axles 130,000 pounds

Gross Tandem Weights

  • Single axle 20,000 pounds
  • Tandem axle 40,000 pounds
  • Tridem or Quad axle 60,000 pounds

**A Quad axle greater than 60,000 lbs. has to be reviewed by engineering on the requested route of travel**

Multiple Trip Permit:

A truck-specific, multiple trip permit shall be issued for the movement of a non-divisible load, mobile home or containerized cargo. The default allowances are as follows:

1) Non-divisible loads: up to 14 wide, 13’6 high and 90,000 lbs gross weight on 5 or more axles (not to exceed 40,000 lbs. per tandem).
2) Mobile Homes: up to 14 wide, 13’6 high and legal weight.
3) Containerized Cargo: up to 8’6 wide, 13’6 high and 90,000 on 5 or more axles (not to exceed 40,000 lbs. per tandem).

Multiple Trip Permits for Non-Divisible loads and Mobile Homes can obtain a route specific permit for loads up to a maximum height of 15 feet and up to 130,000 lbs. gross weight.

Multiple Trip Permit and OSOW Truck Route Map

A Multiple Trip Permit, up to 100,000 lbs., shall be issued to use in conjunction with the Truck Route Map for Non-Divisible or Containerized Cargo loads. The permit allows up to 100,000 lbs. gross weight and 14 feet in width, with a maximum axle weight of 20,000 lbs. on a single, 48,000 lbs. on a tandem and 55,000 lbs. on a tridem, not to exceed 100,000 lbs. gross weight.

Superloads

Any non-divisible load exceeding 130,000 pounds and/or any single axle weight that exceeds 20,000 pounds will require additional routing analysis. This process may take up to 5 business days.

A load exceeding 180,000 pounds must be submitted with a Certificate of Insurance or have a Certificate of Insurance form on file with the SC Permit office.

A load exceeding 200,000 pounds may require the carrier to provide an independent structural analysis performed by a licensed/registered engineer.

A load exceeding 300,000 pounds must be submitted with the manufacture’s documentation providing the weight and dimensions of the load being transported along with documentation on the empty weight of the truck and trailer used to transport the load.

A load exceeding 500,000 pounds will be assessed an additional mega load impact fee on the entire gross vehicle weight on a pounds per mile basis. 

Source of information: https://www.scdot.org/business/permits-osow.aspx
https://www.scdot.org/business/pdf/osow/OSOW_Guidelinesfor_movement.pdf
https://ops.fhwa.dot.gov/freight/sw/overview/index.htm

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