The structural integrity and the life span of a highway will be ensured if the highway is properly maintained and if the loads moving on the system do not exceed the weight limits that the highway is designed to carry. However, the state's investment in its highways is jeopardized if vehicles exceed the weight limits for which the highway was designed. To help prevent rapid deterioration of the nation's highways from the operation of overweight vehicles, federal and state governments have established laws and regulations limiting the weight of vehicles traveling on the system. The federal government restricts truck weight on interstate highways through a total gross vehicle weight limit of 80,000 pounds, with limits also on the weight of each axle. In addition, a bridge formula has been adopted that specifies the maximum allowable weight on any group of consecutive axles.
Federal law requires each state to enforce the federal weight limits.
Failure to enforce these limits can jeopardize a state's federal highway funding. Texas law generally sets the weight and size limits for state and interstate highways at 80,000 pounds. In addition, there are also limits on the legal width, height and length of vehicles. For example, the permit may specify the time of day the load can be transported and the route the vehicle is to travel. The majority of overweight vehicles are limited to single-trip permits.