An axle load is the entire weight, encompassing the breadth of the vehicle, that the wheels transmit to the road. Axle load is significant for engineers, who design roadways to accommodate trailer traffic and decrease the maintenance necessary for fixing potholes, ruts and cracks.
The hauling capacity is essentially a vehicle's ability to safely tow a specific weight. Manufacturers build the hauling capacity into vehicles on the basis of the expected drivers, destinations and usages of the vehicles.
The federal interstate system hauling capacity limit is the lesser of 20,000 lb. for a single-axle trailer or 600 lb. per inch on the axle based on total tire width. Grandfathered rights in some states allow higher limits.
