What counts as overweight on US highways?
Federal interstate weight limit is 80,000 lbs gross under 23 CFR §658.17. State limits on non-interstate highways vary, but most match the 80,000 lb federal default. Anything above 80,000 lbs gross or above any state's axle-weight limits requires an overweight permit in each state of travel. Some states allow higher GVW on specific routes for grandfathered configurations.
The federal interstate weight limit of 80,000 lbs gross applies to all interstate highways under 23 CFR §658.17 and the related state-by-state federal-bridge formula. State-route weight limits vary — most match the 80,000 lb federal default, some are lower on certain routes (typically 73,000-77,000 lbs).
Axle-weight limits are a parallel constraint. The federal default is 20,000 lbs single-axle, 34,000 lbs tandem-axle. A load that is under 80,000 lbs gross but exceeds an axle-weight limit (because of weight distribution) still triggers an overweight permit. State axle limits sometimes match federal; sometimes lower.
Some states allow higher GVW on specific routes through grandfathered configurations or special-corridor designations. Michigan up to 164,000 lbs on certain configurations, Wyoming up to 117,000 lbs on specific corridors. These higher limits do not extend across state lines — each state's permit is independent.
For practical operations: any load above 80,000 lbs gross or above standard axle limits needs an overweight permit in every state of travel. The permit fee scales roughly with weight and miles — typically $50-$500 per state per trip plus our service fee.