The Safe Trucking Act:
Flexible Truck Weight Reform for Safe, Greener, More Efficient Transportation
The U.S. needs responsible truck weight reform. For more than 30 years, the federal vehicle weight limit
has been set at 80,000 pounds—a restriction that now challenges our economy, environment and infrastructure. About a quarter of
U.S. truck shipments meet this limit with significant space in their trailers, meaning that shippers use more truckloads, miles and fuel
than necessary.
With nearly 70 percent of all U.S. freight tonnage moved by trucks and overall freight tonnage expected to grow nearly 25 percent
over the next decade1, we need solutions now to make trucking more productive. Without responsible truck weight reform, the U.S.
will sink deeper into a capacity crisis that is already threatening economic productivity and environmental sustainability.
Congress should enact the Safe, Flexible and Efficient Trucking Act (Safe
Trucking Act) to safely make truck transportation more sustainable.
Responsible, Flexible, State-Based Reform: Each state would have the option to set Interstate System weight
limits of up to 91,000 pounds, but only for vehicles equipped with six axles rather than the typical five. These vehicles are no bigger or
longer than standard 80,000-pound five-axle trucks. The legislation does not reduce any state and local authority over non-Interstate
System roads.
Comparable Safety & Handling: The U.S. DOT found that the Safe Trucking Act configuration features comparable
handling characteristics and improved braking ability, stopping one foot faster than the 80,000-pound five-axle truck currently used
throughout the nation.2 The Safe Trucking Act also enables the U.S. DOT to require additional safety equipment for these vehicles,
creating a world-class standard vehicle for the movement of heavy goods.
Bridge Formula Compliant: The Safe Trucking Act configuration is “federal bridge formula compliant”—meaning that it
meets weight distribution requirements for vehicles traveling on bridges on the Interstate Highway System.3 The U.S. DOT also found
that wide use of the Safe Trucking Act configuration would not cause any increase in one-time rehabilitation costs for Interstate
bridges.4
Significant Pavement Cost Savings: By decreasing the weight per-axle and per-tire, the Safe Trucking Act
configuration would yield significant pavement wear savings—as much as 4.2 percent of total pavement restoration budgets.5
Minimal Rail Diversion: The U.S. DOT found, assuming wide use of the configuration, that the Safe Trucking Act
configuration would shift cargo from less productive trucks to the more productive trucks allowed by this legislation. Impact on rail was
found to be minimal, estimated as diverting less than one-third of 1 percent of rail revenues (less than $200 million in rail freight each
year)—an amount that is easily offset by the projected annual growth rate of freight rail.6 Under the state option approach, diversion
likely would be even less.
The Safe Trucking Act is supported by a growing body of research and
empirical data.
Safe Roads: The Safe Trucking Act configuration not only features handling that is
comparable to the typical truck configuration; by improving overall trucking
efficiency, it will help make roads safer.
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A significant factor in the number of vehicle/tractor-trailer accidents is vehicle miles traveled. Reducing the number of trucks
needed to deliver a specific amount of freight would help reduce vehicle miles traveled and therefore help make roads safer.7
Since the United Kingdom similarly raised its gross vehicle weight limit for six-axle vehicles in 2001, fatal truck-related
accident rates had declined by 35 percent by 2006. More freight had been shipped, but the vehicle miles traveled to deliver a
ton of freight had declined.8
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A 2009 Wisconsin DOT study found that if a law like the Safe Trucking Act had been in place in 2006, it would have reduced
truck-related accidents in the state.9 Analysis of the study by the American Trucking Associations projects that the Safe
Trucking Act configuration would have prevented a total of 90 accidents in Wisconsin in 2006.
Safe Roads: The Safe Trucking Act will allow heavier trucks onto Interstate highways—
the safest place for heavier traffic.
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Within the U.S., more than 90 percent of states allow heavier trucks to access some or all secondary roads, but federal
regulations keep them off the Interstate—the safest place for truck shipments. In addition, many of the heavier trucks that
are already permitted on state roads operate on five axles—instead of the safer six axles required by the Safe Trucking Act.
In 2011, Congress allowed Maine to grant Interstate access to heavier, six-axle trucks. Since then, Maine highway fatalities
have reached a 70-year low and fatalities involving commercial trucks have been reduced from 23 in 2009 to 10 in 2014.10
Cleaner Environment: The Safe Trucking Act will save fuel and reduce
greenhouse emissions.
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Six-axle trucks loaded to 91,000 pounds allow shippers to move a given amount of product with a median reduction in fuel
consumption of 13 percent, relative to five-axle trucks carrying 80,000 pounds.11
The U.S. DOT estimates implementation of the 91,000-pound six-axle configuration would "result in a decline in fuel costs,
carbon dioxide emissions...and emissions of nitrogen oxide."12
Stronger Economy: The Safe Trucking Act will help U.S. manufacturers confront
the capacity crunch while stimulating investment and economic growth.
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Demand for both truck and rail shipment is growing, and capacity constraints are extraordinarily tight, with demand for truck
shipment far outpacing truck availability. Truck weight reform would help address this capacity crisis.
By allowing companies to consolidate goods and reduce the number of weekly shipments, the U.S. DOT estimates the
impact of implementing the Safe Trucking Act configuration would reduce logistics costs by 1.4 percent annually, yielding
“significant logistics savings” of approximately $5.6 billion.13
U.S. gross vehicle weight limits are among the lowest of all industrialized nations. Canada, Mexico and most European
nations already employ higher vehicle weight limits—putting U.S. shippers at a competitive disadvantage.14
Infrastructure Friendly: The Safe Trucking Act configuration would reduce road
wear and minimize bridge impact.
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By lowering axle weight limits, the Safe Trucking Act configuration reduces pavement costs by as much as 4.2 percent.15
In addition to stating that the Safe Trucking Act configuration is bridge formula compliant, the U.S. DOT found that one-time
bridge rehabilitation costs for Interstate System bridges are the same with wider use of the Safe Trucking Act vehicle as with
today’s five-axle 80,000-pound configuration.16
ATA U.S. Freight Transportation Forecast to 2025, American Trucking Associations, 2014.
U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. II, “Highway Safety and Truck Crash Comparative Analysis,” June 2015, pp. 60-65.
3 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” June 2015, p. 20; and U.S. DOT Deputy Administrator
Gregory G. Nadeau Letter to Congressman Reid J. Ribble, April 24, 2015
4 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. II, “Bridge Structure,” June 2015, pp 62-63.
5 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” June 2015, pp. ES-8, ES-11.
6 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” June 2015, p. 39.
7 Carson, Directory of Significant Truck Size and Weight Research, NCHRP 20-07 Task 303, 2011, p. 49; Wisconsin Truck Size and Weight Study, Wisconsin Department of
Transportation, 2009, p. ES-13.
8 Transportation Statistics Bulletin: Road and Freight Statistics 2007, UK Department for Transport, 2008.
9 Wisconsin Truck Size and Weight Study, Wisconsin Department of Transportation, 2009, p. 8-3.
10 “Road Deaths at 70-Year Low in Maine,” Bangor Daily News, Jan. 12, 2015.
11 Analysis of the Potential Benefits of Larger Trucks for U.S. Businesses Operating Private Fleets; University of Michigan Transportation Research Institute; 2009, p. 13.
12 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” p. ES-6.
13 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” June 2015, pp. ES-11, 39.
14 International Vehicle Performance Benchmarking Study, Organisation for Economic Co-operation & Development (OECD), 2008.
15 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. I, “Technical Summary Report,” June 2015, p. ES-11.
16 U.S. DOT Comprehensive Truck Size & Weight Limits Study Technical Reports, Vol. II, “Bridge Structure Comparative Analysis,” June 2015, pp. 62-63.
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