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Truck Weights and Lengths: Assessing the Impacts of Existing Laws and Regulations








JULY 9, 2008


Chairman DeFazio, Ranking Member Duncan, and Members of the Subcommittee, thank you for the opportunity to appear before you today to discuss Federal regulation of commercial motor vehicle size and weight.    

We have a proud history at the Federal Highway Administration (FHWA), and our most important chapter so far began with President Eisenhower’s grand vision to connect America in a way that moved people and goods from city to city and State to State in a safe, efficient, and reliable way.  Although construction of the Interstate System has been completed, we are not done yet.  President Eisenhower’s vision does not stop at concrete and guardrails--we continue to carry the responsibility for ensuring that the system provides safe, efficient, and reliable mobility for America.

As we all work together to provide that service to America, we must be sure to maintain our existing infrastructure and do all we can to ensure efficient freight movement.  Key to those goals are the commercial motor vehicle size and weight requirements.  FHWA is responsible for monitoring and enforcing Federal commercial motor vehicle size and weight limits--requirements that preserve the physical condition of the highway transportation system and the safety of its users.  Meeting the freight transportation needs of a growing economy in a safe and efficient manner is the challenge for all of us involved in this endeavor.

Federal involvement in commercial motor vehicle size and weight dates back to the enactment of the Federal-Aid Highway Act of 1956 (Public Law 84-627), which authorized the Interstate System. That Act established weight limits to protect the Federal investment in the Interstate System from excessive damage caused by overweight commercial vehicles.  The 1956 law included a maximum width limit of 96 inches, a single-axle weight limit of 18,000 pounds, a tandem-axle weight limit of 32,000 pounds, and a gross vehicle weight (GVW) limit of 73,280 pounds.  These Interstate limits were established as a condition on the receipt of Federal-aid funds, and failure to implement or enforce the limits resulted in the withholding of Federal funds.  It is important to note, however, that the 1956 Act also included a grandfather clause allowing States to retain any higher axle and GVW limits they had already enacted, as well as their authority to continue issuing overweight permits under the conditions in effect that year. 

The Federal-Aid Highway Amendments of 1974, Public Law 93-643, became effective in 1975, increasing the Federal axle weight limits to the maximum allowed today—20,000 and 34,000 pounds for single- and tandem-axles, respectively.  This law also set the maximum GVW at 80,000, provided the vehicle complies with the Federal bridge formula, which sets maximum gross weight limits for groups of axles in accordance with the number and spacing of the axles.  These Federal limits were maximums only, and several States chose to retain their lower, pre-1975 Interstate limits.  The disruption to national uniformity created by these so-called “barrier States” prevented motor carriers from fully utilizing the new higher weight limits.

The Surface Transportation Assistance Act of 1982 (Public Law 97-424) addressed this situation by making the 1975 maximum weights also the minimums States must allow on the Interstate System.  This Act also expanded the Federal regulation of commercial vehicle size by requiring FHWA to designate a National Network of highways, including the Interstates, where States must allow commercial vehicles of certain dimensions and configurations to operate.  This Act preempted the States from enforcing laws and regulations that would impose on this National Network trailer length limits of less than 48 feet for truck tractor-semitrailer combinations, or less than 28 feet for truck tractor semitrailer-trailer combinations (doubles), or imposing an overall length limitation of less than 45 feet for buses.  States were prohibited from denying reasonable access for these vehicle combinations to terminals; facilities for food, fuel, repairs and rest; and points of loading and unloading for household good carriers.  The 1982 Act also established a maximum/minimum width limitation of 102 inches, grandfathered certain trailer dimensions in actual and lawful use in 1982, and authorized FHWA to adopt regulations to accommodate specialized equipment, such as automobile transporters.  These requirements remain in effect today.

Size and weight changes in the 1982 Act were accompanied by changes in Federal truck taxes to better reflect the cost responsibility of heavy trucks.  In addition to the tax on diesel fuel, there is a 12 percent excise tax on new truck and trailer sales, a tax on truck tires, and a heavy vehicle use tax that varies according to truck weight.  Except for the diesel fuel tax, rates for other truck taxes generally have not changed since 1982.  The last Federal highway cost allocation study, completed in 2000, showed that many of the heaviest trucks pay considerably less than their highway cost responsibility.  While not recommending immediate changes in truck tax rates, that study indicated that if truck size and weights were changed in the future, changes in Federal truck taxes should also be evaluated to match appropriately the pavement and bridge wear caused by the heavier trucks.

Even though the maximum GVW for commercial motor vehicles on the Interstate System was set at 80,000 pounds in 1975, a number of States interpreted their grandfathered permit authority broadly and allowed the operation of increasingly heavy trucks that came to be known as longer combination vehicles (LCVs).  An LCV is any combination of a truck-tractor and two or more trailers or semitrailers operating on the Interstate System with a GVW greater than 80,000 pounds.  In 1991, the Intermodal Surface Transportation Efficiency Act (ISTEA)(Public Law 102-240) froze the weight of LCVs on the Interstate and the length and configuration of longer double- and triple-trailer combinations on the National Network.  Referred to as the “ISTEA freeze,” those limits are now listed in Federal size and weight regulations (23 CFR Part 658, Appendix C).

            The current, statutorily established, truck length and width restrictions apply on the National Network.  This network covers approximately 209,000 miles of roadway and includes the Interstate System and certain other principal arterial roadways designated by the States and incorporated in Federal regulation.  Weight restrictions apply on the Interstate System, which encompasses approximately 47,000 miles of limited access, divided highways that span the Nation.  Beyond the Interstate System, States may set their own weight limits.

FHWA has responsibility for monitoring and enforcing State compliance with Federal standards.  States incorporate Federal size and weight requirements into State law and enforce those laws with State personnel.  States must provide FHWA annual certifications of size and weight enforcement signed by the Governor or his or her designee.  The certifications include an enforcement plan and updated information on size and weight enforcement activitiesFailure to certify or to enforce adequately all Federal size and weight requirements can result in a ten percent reduction of certain Federal-aid funds to the State in the subsequent fiscal year.

If a State enacts laws or regulations establishing weight limits for commercial motor vehicles that violate the Federal weight standards, the State is subject to loss of its entire National Highway System (NHS) apportionment.  In addition, if a State violates the Federal size requirements, the State is subject to a civil action for injunctive relief in Federal district court.  To date, FHWA has not permanently withheld funds from any State, though it has sought and obtained injunctive relief in rare cases.  Over the years, we have initiated sanctions, but States have returned to compliance, and further action was not required.  The severity of the potential sanctions appears to incentivize State compliance with the Federal laws.    

In both the certification and the enforcement plan submittals, States notify FHWA of changes proposed in their truck size and weight laws and regulations, which we use to determine whether the proposed changes would conflict with Federal law.  The information provided in the certifications also addresses the State administration and issuance of special permits for overweight or oversize loads. 

There are times when heavy loads need to move on the Interstate system, including loads carrying generators for power supply in emergencies, windmill turbines and blades for generating power, or manufactured housing.  Federal law allows all States to issue permits for oversize or overweight loads that are non-divisible.  Federal regulations define as non-divisible any load or vehicle exceeding applicable length or weight limits which, if separated into smaller loads or vehicles, would compromise its intended use, destroy its value, or require more than eight work hours to dismantle.  Some States also have authority to issue permits for overweight divisible loads, pursuant to their 1956 grandfather rights.  FHWA monitors State permitting programs for consistency with Federal permitting privileges. 

The smooth and secure flow of freight is vital to our nation's economy and to our global competitiveness.  Keeping in mind our responsibility to provide a safe, efficient and reliable transportation network to the country, FHWA is engaged in a number of research and program activities related to truck size and weight, a few of which I will highlight for you today.  

FHWA is collaborating with one of our sister agencies, the Federal Motor Carrier Safety Administration (FMCSA), on roadside automated enforcement tools that will support the weighing and inspecting of trucks and enable driver and company validation at highway speeds.  These tools will enable more comprehensive coverage of the system and more efficient monitoring and enforcement of size and weight requirements across the entire network.

For example, our current estimates indicate that less than one percent of the trucks weighed are issued citations for being illegally overweight.  This means that too many trucks at legal weight are having their trips needlessly interrupted.  These smart roadside screening tools will identify trucks that exceed pre-established enforcement thresholds, enabling more efficient and effective enforcement of size and weight requirements.  This effort can improve productivity without compromising safety or infrastructure preservation. 

As part of the Department’s Congestion Initiative, we are looking at the possibility of improving freight movement through truck-only lanes, by which we mean lanes physically separated from passenger vehicles.  We are exploring this idea with partners and stakeholders.  Together, we are conducting a benefit-cost analysis to determine the economic feasibility of truck-only lanes.  Part of this discussion has included the operational parameters that would warrant the construction of such lanes, including the percentage of trucks in the traffic stream, the average annual daily truck traffic on the roadway, and the proximity of large freight generators.  We are also considering whether changes to size and weight restrictions would be necessary to make these truck-only lanes economically viable.  To date, we have held two forums with the trucking industry and the safety advocates to solicit their viewpoints and recommendations.  We will continue to engage shippers, the trucking industry, safety advocates and the public in future discussions of this option.  Additionally, the Corridors of the Future Program is giving us the chance to develop multi-State, corridor-wide strategies to create congestion relief.  One such corridor is I-70 where the participants will be studying the feasibility of dedicated truck lanes.

As noted earlier, States have substantial authority to control the conditions under which oversize or overweight loads may move, especially nondivisible loads.  Divergent State permitting practices sometimes present a challenge to the transport of oversize loads across State boundaries, as is the case for trucks carrying manufactured housing in several Northeastern States.  FHWA has facilitated discussions among industry executives and State permit officials to reach a consensus on more efficient, coordinated movements of oversize loads in this region.  With the support of the Northeast Association of State Transportation Officials (NASTO), we are moving toward a pilot for harmonized permitting activities in 2009.  FHWA will use this initiative as a template for solving complex, multi-state truck mobility issues that arise in other areas of the country.  We also are working closely with other regional organizations of AASHTO, like the Western Association of State Transportation Officials (WASHTO), and the Southern Association of State Transportation Officials (SASHTO) on this issue of streamlining the permit process and seeking interoperability between States.

FHWA and its sister agencies in DOT are focused not only on infrastructure preservation but on keeping America moving by improving the safety, security, productivity and mobility of the Nation’s highway transportation system.  With these objectives in mind, we look forward to continued work with you, the public, and stakeholders.

Thank you for the opportunity to appear before you today.  I would be happy to answer questions.


Jeffrey F. Paniati, Executive Director, Federal Highway Administration
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