Alabama commercial vehicle weight limits follow the federal Interstate standard of 80,000 lbs gross, 20,000 lbs per single axle, and 34,000 lbs per tandem axle group. The federal bridge formula (23 U.S.C. 127) applies on all routes. No seasonal weight restrictions on Interstate highways. Oversize and overweight permits are available from AL DOT for loads exceeding standard limits. Verify current road-specific postings with the Alabama DOT before routing heavy loads.
The federal bridge formula limits the weight on any group of axles based on the distance between the outermost axles in the group. It applies in Alabama on all routes where federal standards apply.
W = maximum weight in lbs · L = axle spacing in feet · N = number of axles
Alabama DOT issues oversize/overweight permits through the Permits Section of the Maintenance Bureau. Single-trip permits required for any load exceeding legal limits. Annual permits available for qualifying repetitive movements. Superloads (extremely heavy or wide loads) require engineering review and pre-approved routing. Port of Mobile drayage and automotive plant supply chain moves frequently require permits for specialized equipment.
Apply for Alabama OS/OW Permit →On Alabama Interstate highways, the maximum gross vehicle weight is 80,000 lbs — matching the federal standard. Alabama state routes and county roads may have lower posted limits that must be observed. Overweight permits from ALDOT are required for loads exceeding 80,000 lbs on any road.
No. Alabama does not impose seasonal spring weight restrictions on its Interstate or primary highway system. The mild Southern climate means Alabama roads do not experience the freeze-thaw damage that drives spring restrictions in Northern states. This makes Alabama a reliable year-round corridor for heavy automotive supply chain and port freight movements.
Alabama oversize/overweight permits are issued by ALDOT's Permits Section. Apply through the ALDOT permit portal at dot.state.al.us. Single-trip permits cover one-time movements. Annual permits are available for qualifying routine operations. Superload permits for extreme weights require engineering review, route surveys, and escort vehicle coordination.
The tandem axle weight limit in Alabama is 34,000 lbs on Interstate highways, matching the federal standard. Tridem axle configurations are allowed up to 42,000 lbs on qualifying routes. State routes and secondary roads may carry lower limits — always verify before routing.
Alabama does not have a blanket automotive plant exemption, but ALDOT regularly works with carriers serving the Mercedes-Benz, Honda, Toyota, and Hyundai plants on permit routing for oversized parts and specialized equipment. Annual permits are available for qualifying repetitive movements. Contact ALDOT's Permits Section to discuss options for your specific operation.
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Disclaimer
The information on this page is compiled from publicly available government sources and is provided for general informational purposes only. TruckRadar is an independent search engine — we are not affiliated with any government agency and this content does not constitute legal or compliance advice. Regulations change frequently; always verify current requirements directly with the official source before making compliance decisions.
Official source: Alabama AL Department of TransportationLast reviewed: 2026-04