Size and weight limits

Scope

The state and federal size and weight limits apply to all vehicles – commercial, private, and non-profit. No limit may be exceeded without a permit from the state in which the vehicle is operated.

Regulatory citations

• 23 CFR 658 — Size and weight, route designations - length, width and weight limitations
• 23 CFR 658.13 — Length
• 23 CFR 658.15 — Width
• 23 CFR 658.17 — Weight

Key definitions

• Bridge formula: The standard specifying the relationship between axle (or groups of axles) spacing and the gross weight that those axles can carry.
• Federal-aid primary system: The Federal-aid highway system of rural arterials and their extensions into or through urban areas.
• Interstate system: The National System of Interstate and Defense Highways.
• National Network (NN): The composite of the individual network of highways from each state on which vehicles authorized by the provisions of the STAA are allowed to operate.

Summary of requirements

The limitations cover the legal limits allowed for width, height, length and weight for various vehicles and/or trailer configurations. They also address the limitations for vehicle traveling on interstate or designated highways within the state and/or other state or supplemental highways.

The federal bridge formula is used for those state roads that the state has designated as being part of the National Network, and while the majority of the states use the federal bridge formula for all roads in their state, some do have a separate state formula they use for other state or county roads.