Federal Bridge Formula Calculator
Enter the distance in feet between the extreme axles in the group and the number of axles in that group.
Formula only
TowAtlas runs the arithmetic from the federal bridge formula. It does not determine route legality, state exceptions, permits or individual axle-group compliance.
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Formula reference
Federal Bridge Formula arithmetic
This tool runs the Federal Bridge Formula using the axle count and spacing you enter. Route, jurisdiction, axle configuration, permits, exemptions and equipment ratings can impose additional requirements, so treat the result as formula arithmetic rather than a legal determination.