Depending on the number of axles and the size of the truck, different weight limits may apply. The traditional 18-wheeler, 63-foot-long, five-axle tractor-trailer, the federal motor safety carrier administration regulates that it should not be more than 80,000 pounds. For three axles, it is 42,000 pounds. For a tandem axle, it is 34,000 pounds. For a single axle, it is 20,000 pounds and a 45,000-pound limitation is generally the level for a flatbed truck.
As provided by Houma truck regulations, what constitutes an overweight truck is a bit different. For 18-wheelers on a Louisiana non-interstate highway, there is an 88,000-pound limitation for the vehicle and load, while on Louisiana interstate highways the weight limitation is 83,400 which is still more than the federally mandated limits. Some exceptions apply such as trucks carrying sugarcane which have a limitation of 100,000 pounds gross vehicle weight, but they are also required to have six axles rather than five axles.