For More Information: https://ops.fhwa.dot.gov/freight/index.cfm
Contact Information: John.Berg@dot.gov
Authorization of the “Dwight D. Eisenhower System of Interstate and Defense Highways” (the Interstate Highway System) in the 1950s created an interest in preserving the integrity of highways built with federal funds. Federal interest in the nation’s highway system also extends to ensuring the safety, productivity, and mobility of freight commerce.
The national Vehicle Size and Weight Team, a part of the Federal Highway Administration’s (FHWA’s) Office of Freight Management and Operations, oversees state enforcement of heavy truck and bus size and weight standards in the United States. The Vehicle Size and Weight Team is assisted by FHWA’s policy and legal staff. Additionally, staff in each of FHWA’s 52 Division Offices provide one-on-one support to individual states, the District of Columbia, and Puerto Rico. Washington Headquarters and Division Office staff also assist with policy questions, clarifications, reporting requirements, training, and other related program and administrative issues.
Trucks entering weigh station for weight compliance check.
Federal standards center on a commercial vehicle’s weight, length, and width. Specific details of the standards follow.
Commercial Vehicle Weight Standards
National weight standards apply to commercial vehicle operations on the Interstate Highway System, an approximately 40,000-mile system of limited access, divided highways that spans the nation. Off the Interstate Highway System, states may set their own commercial vehicle weight standards.
Federal commercial vehicle maximum standards on the Interstate Highway System are:
|Single Axle:||20,000 pounds|
|Tandem Axle:||34,000 pounds|
|Gross Vehicle Weight:||80,000 pounds|
Bridge Formula Weights
The bridge formula was introduced in 1975 to reduce the risk of damage to highway bridges by requiring more axles, or a longer wheelbase, to compensate for increased vehicle weight. The formula may require a lower gross vehicle weight, depending on the number and spacing of the axles in the combination vehicle.1
National vehicle size standards apply on what is known as the National Network of highways. The National Network includes: (1) the Interstate Highway System and (2) highways, formerly classified as Primary System routes, capable of safely handling larger commercial motor vehicles, as certified by states to FHWA. The total National Network system is about 200,000 miles. (See table for specific limits.)
Federal Commercial Vehicle Size Limits on the National Network
Overall vehicle length
No federal length limit is imposed on most truck tractor-semitrailers operation on the National Network.
Exception: On the National Network, combination vehicles (truck tractor plus semitrailer or trailer) designed and used specifically to carry automobiles or boats in specially designed racks may not exceed a maximum overall vehicle length of 65 feet, or 75 feet, depending on the type of connection between the tractor and trailer.
Federal law provides that no state may impose a length limitation of less than 48 feet (or longer if provided for by grandfather rights) on a semitrailer operating in any truck tractor-semitrailer