Higher Crash Rates and Longer Stopping Distances
In its 2016 Final Report to Congress, the U.S. Department of Transportation (USDOT) confirmed its 2015 findings that heavier trucks have 47 to 400% higher crash rates in limited state testing (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Highway Safety and Truck Crash Comparative Analysis Technical Report, 2015; pg. 26, Table 8).
USDOT also found in the report that longer double-trailer trucks take 22 feet longer to stop than twin-trailer trucks on the road today (June 2015 Highway Safety and Truck Crash Comparative Analysis Technical Report, Table 26, pg. 65).
In the report’s conclusion, USDOT recommended that Congress make no changes to current truck size and weight laws and regulations (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Final Report to Congress, 2016; pg. 21).
USDOT also had previously found that multi-trailer trucks—doubles and triple-trailer trucks—”could be expected to experience an 11% higher overall fatal crash rate than single-trailer combinations” (USDOT Comprehensive Truck Size and Weight Study, 2000; Vol. 3, Chapter 8, pg. VIII-5).
Heavier trucks tend to have a higher center of gravity because the additional weight is typically stacked vertically. Raising the center of gravity increases the risk of rollovers.
Also, triple-trailer trucks are more likely to experience trailer sway and the “crack-the-whip” effect (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Technical Reports, 2016; Vol. 1: Technical Reports Summary, pg. ES-12).
- U.S. Department of Transportation; 2016. Comprehensive Truck Size and Weight Limits Study, Final Report to Congress
- U.S. Department of Transportation; 2015. Comprehensive Truck Size and Weight Limits Study, Volume 1: Technical Reports Summary
- U.S. Department of Transportation; 2015. Comprehensive Truck Size and Weight Limits Study, Highway Safety and Truck Crash Comparative Analysis Technical Report
- U.S. Department of Transportation; 2013. Highway Safety and Truck Crash Comparative Analysis, Final Draft Desk Scan
- Multimodal Transportation and Infrastructure Consortium; 2013. An Analysis of Truck Size and Weight: Phase I – Safety, as revised September 29, 2014, Matthews Memorandum
- U.S. Department of Transportation; 2004. Western Uniformity Scenario Analysis
- U.S. Department of Transportation; 2000. Comprehensive Truck Size and Weight Study
- California Department of Transportation; 1984. Longer Combination Vehicle Operational Test
We already face a national infrastructure crisis. More than half the bridges on the National Highway System are more than 40 years old, and nearly 25 percent are already either structurally deficient or functionally obsolete (FHWA Deficient Bridges by Highway System, 2015).
According to USDOT, heavier and longer trucks would have negative impacts on infrastructure. Increasing truck weight limits to 91,000 pounds would negatively affect more than 4,800 bridges, incurring up to $1.1 billion in additional federal investment (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Final Report to Congress, 2016; pg. 10, Table 2). Further, 97,000-pound trucks would negatively affect more than 6,200 bridges, incurring up to $2.2 billion in additional funding (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Final Report to Congress, 2016; pg. 10, Table 2).
USDOT found that longer double-trailer trucks would require nearly 2,500 Interstate and other National Highway System bridges to be posted or face further damage, costing up to $1.1 billion in immediate bridge strengthening or reinforcement (USDOT MAP-21 Comprehensive Truck Size and Weight Limits Final Report to Congress, 2016; pg. 11, Table 3).
Instead of a bridge bailout costing billions of dollars, why not preserve the bridges we already have?
Bigger trucks are such a threat to our nation’s local infrastructure that over 1,000 community leaders from across the country – including mayors, county engineers and public works directors – delivered a letter to Congress in 2018 asking policymakers to oppose any increases in truck size or weight, including longer double-trailer trucks and heavier single-trailer trucks (“Bigger Trucks: Bad for America’s Communities,” 2018).
Our highways and bridges are in rough shape because we don’t have the resources to keep them in good condition. Allowing even bigger trucks would only make this problem even worse because they damage our nation’s infrastructure.
Bigger trucks mean bigger spending, bigger deficits.
The most recent federal study to look at the issue showed that allowing 97,000-pound single-trailer trucks would result in trucks only paying for 50% of the damage they cause. Also, 110,000-pound triple-trailer trucks would only pay for 70% of their damage.
History Reveals A Pattern
Congress last increased the federal weight limit in 1982. Then, as now, those pushing for bigger trucks said it would result in fewer trucks on the road, but that never happened. In fact, the number of trucks registered in the U.S. and the mileage of trucks traveled has steadily increased.
Nearly 8 Million More Trucks
A June 2020 study, commissioned by the Coalition Against Bigger Trucks, shows major diversion of freight traffic from rail to truck if longer and heavier trucks are allowed by Congress.
This study shows some “. . . scenarios will reduce intermodal traffic by 20-25 percent and railroad carload traffic by as much as 20 percent. More disruptive scenarios could reduce both intermodal and certain carload traffic by nearly 60%.” Click here to read the full study.
A previous study conducted in 2010 concluded that an increase from the current 80,000-pound weight limit to the proposed 97,000-pound weight limit could reduce overall rail traffic by 19% (Martland, 2010; pg. 14, Table 10). The same study found that diverted freight will inevitably find its way onto the highway, resulting in 8 million more trucks on our roads and bridges—a 56% increase. This influx would not only further endanger motorists, but cause exponential damage to our nation’s roads and bridges.