3.2 Maximum Load without Permit
Per the Federal Highway Administration (https://ops.fhwa.dot.gov/freight/sw/overview/index.htm), the following weight limits are allowed without the requirement of a special permit.
On the interstate highway system:
- Single axle: 20,000 lbs
- Tandem axle: 34,000 lbs
- Gross vehicle weight: 80,000 lbs
Thus, with an unloaded weight of approximately 30,000 lb for a tractor-trailer combination, a maximum load of approximately 50,000 lb can be carried by the truck without the need for a permit.
On non-interstate highways, states may set their own commercial vehicle weight limits.
Additional information about federal weight limits can be found at the following sources: