DOT: Data limitations prevent meaningful findings from being reached in truck size and weight study

Late last week, the United States Department of Transportation (DOT) formally released its long-awaited Comprehensive Truck Size and Weight Limits Study, which was a requirement of the current federal surface transportation bill known as Moving Ahead for Progress in the 21st Century Act (MAP-21).

The study’s objective, according to DOT, was to “conduct a comparative analysis of the impacts from trucking operating at or within current Federal size and weight regulations to trucks operating above those limits, with attention focused on six-axle tractor trailers and other alternative configurations,” and other factors, including: highway safety and truck crash rates, vehicle performance (stability and control), and inspection and violation patterns; pavement service life; highway bridge performance; and truck size and weight enforcement programs.

One of the chief goals of the study was to assess the impacts that changes in TSW might have in areas of the study to learn the impacts that trucks operating above current Federal TSW limits have. And DOT said a “key step” was to estimate the effects that changes in current Federal TSW could be projected to have on freight movement by truck type, roadway type, and freight transportation mode.

While the objectives of the study were ambitious, its findings did not yield anything of true significance, because of what DOT called data limitations.

“[E]fforts to assess the full effects of the size and weight of various trucks are hindered by many of the same significant data limitations identified in previous studies,” DOT said. “The Department finds that the current data limitations are so profound that no changes in the relevant laws and regulations should be considered until these data limitations are overcome.”

DOT said the data limitations include, as an example, a lack of descriptive information in crash reports, especially the weight of the commercial motor vehicle at the time of an incident, which undermines its ability to conduct highway safety and truck crash analyses.

And the lack of weight data in crash reporting, the DOT explained, prevents it from knowing if trucks were fully loaded, at legal capacity for that axle configuration, had unevenly distributed weight or were running overweight prior to a crash.

Other examples included: small or non-existent data sets for crashes and citation and violation data sets in certain alternative configurations; the lack of an acceptable model that estimates the impact of trucks of varying weights on bridge decks and long-term maintenance costs over time and across the national network; limited publicly available data which affected DOT’s ability to estimate impacts on short line and regional railroad movements; and difficulty separating truck weight enforcement program costs from overall truck safety enforcement cost.

American Trucking Associations President and CEO Bill Graves blasted the DOT’s findings.

“Given the timing of the release of this study, it is an obvious attempt to promote administration policy, rather than give Congress the unbiased information it requested,” he said in a statement. “It is appalling that after years of saying the study would not make recommendations, DOT officials would release this report – and recommend no change in current law – just days after the White House came out opposing truck productivity increases. Our experience as an industry, as seen by the safe and efficient use of twin 33-foot trailers in the states of Florida and North Dakota, shows the obvious benefits of this configuration,” he said. “As flimsy as this report is, it at least acknowledges these more productive combinations will improve efficiency, saving American consumers billions of dollars.

The use of twin 33-foot trailers has been cited many times by carriers a way to increase both TSW and overall production. On his company’s fiscal third quarter earnings call earlier this year, top FedEx executive Fred Smith stated that: “The biggest single thing that could be done in this country that would help the environment and improve the productivity of our logistics system would be for the federal government to change the limit of the twin trailers used by the Ground parcel and LTL industries from 28 feet per trailer to 33 feet per trailer, and that gives about 18% more cube.”

He added that trailers typically cube out before they weigh out, also noting that there is an immediate productivity increase along with a system more suited to today’s e-commerce world than are 28-foot trailers. Other benefits he noted were increased safety, fuel savings, and lower emissions.

Truck size and weight has long been viewed as a hot button issue in freight transportation and supply chain circles, as well as political ones, too. The case against increasing truck size and weight (TSW) has been built on the premise to keep bigger and heavier trucks off the road and apply existing federal truck size and weight limits to the entire National Highway System, rather than interstate highways, which is the case today. And legislation in recent years that calls for not increasing TSW has included things like longer stopping distances, increased risks of rollover and trailers merging into adjacent lanes, with a 100,000 pound truck with unadjusted brakes moving 25 percent further after a driver applies brakes than an 80,000 pound truck and larger trucks representing a higher share of deaths based on miles traveled compared to standard vehicle traffic, as well as threats to the country’s roads, bridges, and other infrastructure.

“My reaction was the same as that of Governor Graves and ATA,” said John Cutler, General Counsel for the National Shippers Strategic Transportation Council (NASSTRAC) and principal with McCarthy, Sweeney & Harkaway in Washington, D.C. “NASSTRAC has pushed hard for release of the DOT truck size and weight study, because of the importance of consideration of this issue in connection with the next Highway Bill. In addition assessing twin 33-foot trailers, which NASSTRAC supports, DOT could have looked to the multi-year pilot program in Maine, where allowing larger and heavier trucks on interstates has increased safety and improved productivity for shippers and carriers. Congress called for the study to get facts, not policy preferences of the Administration.”

Conversely, though, in 2012, the Safe and Efficient Transportation Act (H.R. 763 and S. 747), gained the support of about 200 shippers, carriers and allied associations, and it authorized the use of higher productivity, six-axle single-trailer vehicles weighing up to 97,000 pounds. Truck lengths would not be affected.
 
The bill called for states to have the option to implement higher weight limits on interstate borders within their limits—where appropriate. Backers said it would result in fewer trucks on the highways, less pollution, reduced emissions, bolster productivity and perhaps save as much as 2 billion gallons in diesel annually.