Size and Weight

A Responsible Approach to Commercial Motor Vehicle Size and Weight Limits

While the Commercial Vehicle Safety Alliance (CVSA) does not take a position on individual proposed changes to existing size and weight limits, CVSA recommends that changes to current CMV size or weight limits not be made without first considering several factors, where applicable:

  • Whether or not subject vehicles are actually designed and manufactured to accommodate the additional weights they will carry;

  • Whether or not the subject vehicles are being properly maintained, with particular attention paid to the wear and tear of the vehicles’ mechanical and load bearing components;

  • Whether or not any new vehicle configuration meets safety performance requirements for the roadways on which it is designed to travel, with consideration given to the possible impact to infrastructure and roadway design; and,

  • Whether or not a minimum set of performance requirements should be established for subject vehicles?

Further, CVSA supports:

  • Giving states the authority to require that passenger-carrying CMVs report to an open weigh station while en route, specifically for weight enforcement purposes.

The nation’s commercial motor vehicle (CMV) industry is diverse and the types of vehicles operating in a particular state or region often vary. Further, driving conditions vary by state due to differences in weather, geography and population density. As a result, care must be taken when crafting responsible size and weight policy. Although safety is always the paramount concern, other considerations, such as environmental impacts, quality of life, productivity, economic competitiveness and impacts to infrastructure, play an important role when considering changes to size and weight laws.

Given the complexity of the subject, CVSA does not take a position on individual proposed changes to existing size and weight limits. Instead, CVSA recommends that changes to current CMV size or weight limits not be made without first considering several factors, where applicable. Those factors include:

  • Whether or not subject vehicles are actually designed and manufactured to accommodate the additional weights they will carry;
  • Whether or not the subject vehicles are being properly maintained, with particular attention paid to the wear and tear of the vehicles’ mechanical and load bearing components;
  • Whether or not any new vehicle configuration meets safety performance requirements for the roadways on which it is designed to travel, with consideration given to the possible impact to infrastructure and roadway design; and,
  • Whether or not a minimum set of performance requirements should be established for subject vehicles?

Ensuring that vehicles can safely handle the weight they are carrying and that the roadways are designed to safely handle the traffic moving across them will help improve safety on our nation’s roadways.

Finally, while the size and weight discussion often focuses on property-carrying CMVs (trucks), as stated above, it is important to understand that all commercial motor vehicles, including passenger-carrying CMVs, are subject to the same weight issues. As the bus and motorcoach industry has evolved, new requirements have been issued mandating additional equipment—for example, handicapped passenger accessories to satisfy Americans with Disabilities Act requirements or diesel emissions equipment to satisfy Environmental Protection Agency requirements—that have added to the empty/tare weight of the vehicle, effectively reducing the passenger weight capacity margin. In addition, the average weight of a passenger today is higher than the decades-old design assumption of 150 lbs per passenger.i Heavier passengers, the advent of high seating capacity double decker buses and the weight of required additional equipment result in the higher likelihood that a bus will be loaded above its allowable weight. Safe carrying capacity of a bus or motorcoach is determined by the manufacturer’s design, in which all component specifications play a part—frame/body, axles, steering components, bearings, and wheels—and particularly brakes and tires. Overloading a vehicle or any of its components increases the risk to passengers and those operating around the vehicle. According to FMCSA, an overloaded tire is more likely to overheat and fail, which could result in a blowout and crash.ii

To help ensure that passenger-carrying vehicles and components are not being overloaded, inspectors need to be able to weigh the vehicle, and have the capability to inspect the condition of the components, as necessary. Enforcement personnel who have identified passenger-carrying CMVs exceeding manufacturers’ designs will take the necessary steps to minimize the impact on the passengers and their trip. This could include the states coordinating with the motorcoach industry to establish uniform procedures providing for passenger needs, including identifying alternative transportation options, ensuring that at the end of the day everyone who travels on our highways arrives home without incident. CVSA supports giving states the authority to require that passenger carrying CMVs report to an open weigh station while en route, specifically for weight enforcement purposes. Standard procedures will need to be put into place to provide for passenger needs when an overloaded vehicle is identified.

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i §567.4 – Requirements for manufacturers of motor vehicles. Federal Motor Vehicle Safety Standards.
http://cfr.regstoday.com/49cfr567.aspx#49_CFR_567p4

ii Motorcoach Safety Advisory Bulletin: Exceeding Tire Load Ratings. Federal Motor Carrier Safety Administration.
http://www.fmcsa.dot.gov/documents/alerts/Motorcoach_Safety_Advisory_Bulletin_Exceeding_Tire_Load_Ratings.pdf