How Heavy Is Too Heavy? States Rethink Truck Weight Limits
The Owner-Operator Independent Drivers Association is warning that heavier trucks could increase safety risks and place additional strain on roads and bridges as states create new exceptions to existing weight limits. Supporters of heavier loads say they could reduce the number of trips needed to move commodities such as milk and grain, while critics point to infrastructure wear and the safety implications of added weight.
Concerns Over Heavier Trucks
OOIDA cites research from the Transportation Research Board and the U.S. Department of Transportation in arguing that policymakers should carefully consider the effects of increasing truck weights. The organization says heavier vehicles could create additional demands on roads, bridges and overpasses, particularly at weaker points in the transportation network.
Roadways can support only a certain amount of weight, and the most restrictive point on a route may be a bridge or overpass. As a result, a vehicle’s allowable weight is ultimately limited by the capacity of the weakest point along the road.
Rather than applying broader weight increases to all trucks, some lawmakers are creating targeted exemptions for specific industries and types of freight. States are allowing heavier loads of commodities such as milk, grain and other goods. Supporters say the changes could reduce the number of trips required, while opponents warn that heavier loads may increase pavement and bridge deterioration.
How Truck Weight Is Measured
Weigh-in-motion systems are increasingly being used to screen trucks without requiring every vehicle to stop at a static scale. Sensors installed in the roadway measure axle weights as trucks travel at highway speeds. In states with advanced systems, the technology can process as much as 80 percent of passing traffic, with only a smaller share of vehicles directed to static scales for additional inspection.
Gross vehicle weight, or GVW, is the total weight of a loaded truck, including the truck itself and its cargo. Every truck also has a maximum gross vehicle weight rating, and the loaded vehicle must remain within the applicable limit.
Federal and State Weight Limits
A fully loaded tractor-trailer can generally weigh up to 80,000 pounds, or 40 tons, under federal highway rules. The applicable limit may vary based on state requirements, axle configuration, spacing and the type of operation.
Common federal dimensional limits for standard commercial vehicles include an overall length of approximately 70 to 80 feet, a width of 8.5 feet and a height of about 13.5 feet, although state requirements and route restrictions can differ.
State laws may also impose separate limits on individual axles and wheels. For example, California Vehicle Code Section 35550(a) sets a maximum gross weight of 20,000 pounds on a single axle and limits the weight supported by one end of an axle to 10,500 pounds.
