Americans For Modern Transportation On The Merits of Twin 33’s

February 9, 2017
The Honorable Bill Shuster
United States House of Representatives
2079 Rayburn House Office Building
Washington, D.C. 20515
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Dear Chairman Shuster,

In a recent letter, the Truckload Carriers Association (TCA) lodged inaccurate claims about the implications of further adoption of Twin 33s, which are already allowed on portions of highways in 20 states nationwide.

Americans for Modern Transportation, as representatives of the multi-faceted business community, supports the widespread adoption of Twin 33s along with a number of other measures to not only fix but also upgrade our transportation system.

Leveraging new technologies, jumpstarting efficiency gains through size adjustments, using better materials in roads, and investing in renewable fuels may shake up some incumbents, but they will deliver great results for American consumers.

Below is a point-by-point rebuttal to TCA’s key arguments, in addition to key facts on Twin 33’s here. We look forward to continue being a resource on this important issue.


The Americans For Modern Transportation Coalition


Impact On Efficiency

  • Point:“Lauded as an opportunity to remove trucks from our roads, Twin 33-foot trailers will actually have the opposite effect.”
  • Counterpoint: In their June 2015 Modal Shift Comparative Analysis Report,the U.S. Department of Transportation Federal Highway Administration found that a shift to Twin 33 trailer combinations would result in a “net reduction of almost 3 billion miles.” (USDOT FHA)


  • Point: “The truckload segment of the trucking industry is vast, representing over 500,000 motor carriers equating to 78 percent of the freight moved by truck, based on revenue.”
  • Counterpoint:The less-than-truckload (LTL) and Parcel industry is growing more rapidly than the truckload industry. In fact, LTL volume is projected to grow 3.5 percent annually through 2018 and 2.4 percent through 2024. Truckload volume is projected to grow 3.2 percent and 1.1 percent respectively (ATA’s US Freight Forecast to 2024).


Impact On Trucking And Rail Industries

  • Point: “Pricing models and logistics configurations would prevent the truckload segment of the industry from regaining any dollars invested in new 33-foot trailers. A shift to 33-foot trailers would be considered voluntary, and the shipping community would automatically transition to carriers with the most cubic space for their goods, rendering our nation’s fleet of 53-foot trailers nothing more than antiques.”
  • Counterpoint: The facts are simple. Fifty-three foot trailers cater to an entirely different customer base than any size twin trailers, which are used primarily in LTL networks. Additionally, the current 28-foot trailers have a cubic size advantage over the 53-footers, yet the 53’s remain the workhorse for the entire industry.


  • Point:“In an effort to supplement and improve upon intermodal operations, our nation’s railroad container cars have been developed to accommodate the most prominent trailer configurations that exist within trucking today, the 28- and 53-foot trailers. You will soon realize that any change to these foundational trailer sizes will not only render existing truck trailers obsolete, but their corresponding railroad counterparts as well.”
  • Counterpoint: While it is unclear why TCA feels the need to defend the railroads, again the USDOT has proven their assertion to be false. The June 2015 Modal Shift Comparative Analysis Report analysis found, “the additional cubic capacity of the twin 33-foot doubles compared to existing twin 28-foot doubles is not enough to divert significant amounts of intermodal traffic from the railroads.” Additionally, LTL and small package carriers are among the nation’s largest users of intermodal rail service. Freight put on the rails is primarily moved in 53’ vans or double stack rail trailers because they are the most efficient means.


  • Point: “The truckload industry and its long haul operations are logistically assembled for longer trailer configurations rather than articulating smaller trailers bound by dollies. The majority of loading docks are designed to accommodate trailers that reverse into these docks. The Twin 33-foot trailer configuration has proven problematic to back up and would need to be separated prior to backing, an arduous task for drivers in our long haul world.”
  • Counterpoint:Lydbolt notes Twin 33s are not practical for truckload operations, and we agree. Twin 33s are not economically viable for truckload operations, and practically speaking, Twin 33s can only run designated routes and are impractical for irregular route truckload operations. As every Twin 33 proponent has said, this policy change does nothing to threaten truckload carriers’ current operations or equipment.


Impact On Drivers And Safety

  • Point:“Notably absent from the discussions surrounding 33-foot trailers is the effect that the configuration would have on our population of drivers. As an industry that continually searches far and wide for qualified drivers to operate our vehicles, the driver ramifications of operating fleets consisting of 33-foot trailers would be severe.”
  • Counterpoint: Twin 33s would reduce the national truck driver shortage, while providing better jobs for existing drivers. The growth of the LTL industry provides high-paying and reliable job opportunities. The daily route structure of LTLs ensures drivers get home daily, rather than spending extended time away from home.


  • Point: “The potential for driver injury when separating trailers and their 3,000-lb converter gear is high and would jeopardize any improvements to the health and well-being of drivers that our industry strives to make.”
  • Counterpoint: There is no basis in fact that Twin 33 trailers are less safe than existing trailer configurations. The converter gear for 33s is the same as currently used safely tens of thousands of times each day in current twin 28 operations. The safety facts are well established and AMT member who operate twin 28 fleets are proud to share their amazing safety achievements.


Further Details On Twin 33 Safety Arguments

Twin 33 Trailers Perform Better In Stability And Lane Change Maneuvers Than Widely-Used Twin 28 Trailers. 
“The literature survey showed that longer vehicles tend to have better vehicle dynamic characteristics and in general they have better safety performance…The computer simulation of the two vehicles examined in the study showed that the 33ft double trailer combination was equal to or outperforms the 28ft double trailer combination in four of the measures namely, static rollover threshold, rearward amplification, load-transfer ratio, and high-speed transient off tracking.” (John Woodrooffe & John De Pont, “Comparative Performance Evaluation Of Proposed 33ft Double Trailers Combinations With Existing 28ft Double Trailers,” Woodrooffe Dynamics LLC, 3/11/11)

Long Combination Vehicles Such As Twin 33s Reduce Fuel Use By Up To 21 Percent Annually. “LCVs are more fuel-efficient, on a ton-mile basis, than typical combination trucks. For example, a Rocky Mountain Double consumes 13 percent less fuel per ton-mile of freight, compared to a typical combination truck. This saves over $8,000 in fuel costs per year. Turnpike Doubles and Triples reduce fuel use per ton-mile by 21 percent, saving over $13,000 in annual fuel costs.” (“Longer Combination Vehicles: A Glance A Clean Freight Strategies,” U.S. Environmental Protection Agency, 6/16)

With Widespread Adoption Of Twin 33 Trailers, The LTL / Small Package Trucking Industry Could Absorb 18 Percent Of Future Freight Growth With No Additional Weight Or Increase In Miles Traveled. “It is important to note that this solution does not require any change to gross vehicle weight and, in fact, could reduce the burden on our nation’s highways by significantly slashing the number of trips and miles required to move freight. Based on data supplied by FedEx and six other carriers, including ABF, Con-way, Estes, Old Dominion, UPS, and YRC Worldwide, the use of 33-foot twin trailers would provide a carrier the potential, on any given lane, to absorb up to 18% of future growth, without traveling any additional miles or worsening wear and tear on our roadways. Industry-wide, that equals up to 1.8 billion fewer miles driven, more than 300 million gallons of gasoline saved and $2.6 billion in reduced costs annually. Importantly, a reduction in truck trips would be environmentally friendly, saving fuel and emissions from trucking.” (Henry J. Maier, “Improving The Nation’s Highway Freight Network, Testimony Of Henry J. Maier, President And Chief Executive Officer FedEx Ground Package System, Inc.,” United States House Committee On Transportation And Infrastructure, Subcommittee On Highways And Transit, 2/27/14)