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Chapter 1: Industry Characterization

1.1 Introduction

The proposed fuel consumption and CO2 emissions standards described in the 

preamble of this NPRM would be applicable to three currently-regulated categories of heavyduty vehicles: (1) Combination Tractors; (2) Heavy-duty Pickup Trucks and Vans; and (3) 

Vocational Vehicles, as well as gasoline and diesel heavy-duty engines. The industry

characterization for these sectors can be found in the RIA for the HD Phase 1 rulemaking.1 

With this proposed rulemaking, the agencies would be setting standards for combination 

trailers for the first time. The characterization laid out in this chapter focuses solely on 

trailers as this subcategory would be the only newly-regulated industry.

1.2 Trailers

A trailer is a vehicle designed to haul cargo while being pulled by another powered 

motor vehicle. The most common configuration of large freight trucks consists of a Class 7 or 

8 tractor hauling one or more trailers. Vehicles in these configurations are called 

“combination tractor-trailers” or simply “tractor-trailers”. A trailer may be constructed to rest 

upon the tractor that tows it, or be constructed so part of its weight rests on an auxiliary front

axle called a “converter dolly” between two or more trailers. Trailers are attached to tractors

by a coupling pin (or king pin) on the front of the trailer and a horseshoe-shaped coupling 

device called a fifth wheel on the rear of the towing vehicle or on the converter dolly. A 

tractor can also pull international shipping or domestic containers mounted on open-frame 

chassis, which when driven together on the road function as trailers. 

The Truck Trailer Manufacturers Association, an industry trade group primarily for 

manufacturers of Class 7 and 8 truck trailers, offers publications of recommended practices, 

technical bulletins and manuals that cover many aspects of trailer manufacture, and serves as 

a liaison between the industry and government agencies.2To date, federal regulations for the 

trailer industry are limited to those issued by the Department of Transportation (See 49 CFR). 

These regulations govern trailer dimensions and weight, as well as trailer safety requirements 

(e.g., lights, reflective materials, bumpers, etc.). In addition, DOT requires that each trailer, 

like other on-road vehicles, must have a Vehicle Identification Number (VIN)3. The VIN is 

displayed on a label that is permanently-affixed to the trailer. It is required to contain the 

manufacturer identification, make and type of vehicle, model year, type of trailer, body type, 

length, and axle configuration. Trailer manufactures are responsible for reporting each 

trailer’s VIN information to NHTSA prior to the sale of the trailer.

1.2.1 Trailer Types

Class 7 and 8 tractors haul a diverse range of trailer types. The most common trailer 

type is the box trailer, which is enclosed and can haul most types of mixed freight. The 

general rectangular shape of these trailers allows operators to maximize freight volume within 

the regulated dimensional limits, since the majority of freight shipped by truck cubes-out (is 

volume-limited) before it grosses-out (is weight-limited). Despite considerable improvements 
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in suspension, material, safety, durability, and other advancements, the basic shape of the box 

trailer has not changed much over the past decades, although its dimensions have increased 

incrementally from what used to be the industry’s standard length of 40’ to today’s standard 

53’ long van trailer. Today, box vans are commonly found in lengths of 28’, 48’, and 53’and 

widths of 102” or 96”. The 28’ vans (“pups”) are often driven in tandem and connected by a 

dolly. Current length restrictions for the total combination tractor-trailer vehicle limit tandem 

operation to 28’ trailers. However, some members of the trucking industry are pushing to 

increase the length limits to allow trailers as long as 33’ to be pulled in tandem, and arguing 

that these “less than truckload” (LTL) operations could increase capacity per truckload, 

reduce the number of trucks on the road, reduce the fuel consumption and emissions of these 

tractor-trailers, and remain within the current weight limits.4,5

Trailers are often highly customized for each order. The general structure of the box

trailer type is common and consists of vertical support posts in the interior of the trailer 

covered by a smooth exterior surface. However the exterior of the trailer may be constructed 

of aluminum or a range of composite materials. Historically, floors were constructed of 

wood, however many trailer customers are requesting aluminum floors to reduce weight. 

Semi-trailer axles are commonly a dual tandem configuration, but can also be single, spread 

tandem (i.e., two axles separated to maximize axle loads), tridem (i.e., three axles equally

spaced), tri axles (i.e., three axles consisting of a tandem and a third axle that may be liftable), 

or multi-axles to distribute very heavy loads. Axles can be fixed in place, or allowed to slide 

to adjust weight distribution. Doors are commonly located at the rear of the trailer. The most 

common door is the side-by-side configuration, in which each door opens outward. Roll-up 

doors, which are more costly, allow truck drivers to pull up to loading docks without first 

stopping to open the doors. Roll-up doors are common on trailers with temperature-sensitive 

freight. Additional variations in trailers include side-access doors, or use the underside of the 

trailer for belly boxes or to store on-demand items such as ladders or spare tires. 

The most common box trailer is the standard dry van, which transports cargo that does 

not require special environmental conditions. In addition to the standard rectangular shape, 

dry vans come in several specialty variants, such as drop floor, expandable, and curtain-side. 

Another type of specialty box trailer is the refrigerated van trailer (reefer). This is an 

enclosed, insulated trailer that hauls temperature sensitive freight, with a transportation 

refrigeration unit (TRU) or heating unit mounted in the front of the trailer powered by a small 

(9-36 hp) diesel engine. Figure 1-1 shows an example of the standard dry and refrigerated 

vans.
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Figure 1-1 Examples of dry and refrigerated van

Many other trailer types are uniquely designed to transport a specific type of freight. 

Platform trailers carry cargo that may not be easily contained within or loaded and unloaded 

into a box trailer, such as large, nonuniform equipment or machine components. Platforms 

come in different configurations including standard flatbed, gooseneck, and drop deck. Tank 

trailers are pressure-tight enclosures designed to carry liquids, gases or bulk, dry solids and 

semi-solids. Tank trailers are generally constructed of steel or aluminum. The plumbing for 

intake and discharge of the contents could be located below the tank or at the rear. There are 

also a number of other specialized trailers such as grain (with and without hoppers), dump 

(frameless, framed, bottom dump, demolition), automobile hauler (open or enclosed), 

livestock trailers (belly or straight), construction and heavy-hauling trailers (tilt bed, 

hydraulic).

A sizable fraction of U.S. freight is transported in large, steel containers both 

internationally via ocean-going vessels and domestically via rail cars. Containers are 

constructed with steel sidewalls and external support beams, which results in a corrugated 

exterior. These containers haul mixed freight and are designed with similar dimensions to 

box trailers. Ocean-going international shipping containers are typically 20-feet or 40-feet in 

length. Domestic containers, which often travel by rail, are 53-feet in length. Transport of 

these containers from ports or rail to their final destination requires the container to be loaded 

on a specialty piece of equipment called a chassis. The chassis, which is attached to the fifth 

wheel of a Class 7 or 8 tractor, consists of a frame, axles, suspension, brakes and wheel 

assemblies, as well as lamps, bumpers and other required safety components. Fixed chassis 

vary in length according to the type of container that will be attached, though some chassis 

adjust to accommodate different sizes. When the chassis and container are assembled the unit 

serves the same function as a road trailer.6 However, under customs regulations, the container 

itself is not considered part of a road vehicle.7

ACT Research compiles factory shipment information from a Trailer Industry Control 

Group that represents 80 percent of the U.S. trailer industry. Figure 1-2 shows the 

distribution of trailers sold in the U.S. based on ACT Research’s 2013 factory shipment data. 

The most common type of trailer in use today is the dry van trailer, followed by the 
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refrigerated van. Together, these box vans make up greater than 70 percent of the industry. 

Trailer Body Builders’ annual trailer output report estimates there were over 240,000 trailers 

sold in North America 2013. 

Figure 1-2 ACT Research’s 2013 U.S. factory shipments

1.2.2 Trailer Manufacturers

Trailer Body Builders’ annual trailer output report estimates there were over 240,000 

trailers sold in North America in 2013. The diverse van, platform, tank and specialty trailers 

are produced by a large number of trailer manufacturers. EPA estimates there are 114 trailer 

manufacturers. Trailers are far less mechanically complex than the tractors that haul them, 

and much of trailer manufacturing is done by hand. This relatively low barrier to entry for 

trailer manufacturing accounts, in part, for the large number of trailer manufacturers. Figure 

1-3 shows that over 70 percent of the manufacturing output of the industry comes from just 

five manufacturers. 

56%

15%

9%

2%

3%

2%

3%

1%

4% 4% 1%

ACT Research 2013 Factory Shipments

Dry Van

Refrigerated Van

Platform

HeavyLowbed

MediumLowbed

Dump

Tank Liquid

Tank Bulk

Grain

Other Trailer

Chassis
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Figure 1-3 2013 Trailer Output Report from Trailer Body Builders

Table 1-1 Illustrates the varying revenue among trailer manufacturers and further 

distinguishes the very different roles in that market played by small and large manufacturers. 

The revenue numbers were obtained from Hoovers online company database. 8 Over 80 

percent of trailer manufacturers meet the Small Business Administration’s (SBA) definition of 

a small business (i.e., less than 500 employees), yet these manufacturers make up less than 25 

percent of the overall revenue from the industry. In fact, a majority of the small business 

trailer manufacturers make less than $10 million in revenue per year. 

Table 1-1 Summary of 2013 Trailer Industry Revenue by Business Size

Revenue Range Business Size

All Sizes Large Smalla

> 1000M 1 1 0

$500M - $999M 0 0 0

$400M - $499M 1 1 0

$300M - $399M 0 0 0

$200M - $299M 3 3 0

$100M - $199M 3 3 0

$50M - $99M 13 7 6

$40M - $49M 14 2 12

$15M - $19M 9 1 8

$10M - $14M 3 0 3

$5M - $9M 26 0 26

< $5M 41 1 40

Total Companies 114 19 95

Total Revenue ($M) 4965 3799 1166

Average Revenue ($M) 44 200 12
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Box Trailer Mfrs 14 9 5

Non-Box Trailer Mfrs 109 17 92

Note:

a The Small Business Administration (SBA) defines a trailer 

manufacturer as a “small business” if it has fewer than 500 employees

The trailer industry was particularly hard hit by the recent recession. Trailer 

manufacturers saw deep declines in new trailer sales of 46 percent in 2009; some trailer 

manufacturers saw sales drop as much as 71 percent. This followed overall trailer industry

declines of over 30 percent in 2008. The 30 largest trailer manufacturers saw sales decline 72

percent from 282,750 in 2006, to only 78,526 in 2009. Several trailer manufacturers shut 

down entire production facilities and a few went out of business altogether. Trailer 

production has steadily grown across the industry since 2010 and, although historic 

production peaks have not been repeated to date, it has now returned to levels close to those 

seen in the mid-2000s. Figure 1-4 shows the ACT Research’s annual factory shipments, 

which illustrates the unsteady production over the past 17 years. 

Figure 1-4 Annual Factory Shipments Tracked by ACT Research

1.2.3 Trailer Use

In order to determine the appropriate tractor type for each trailer, the agencies 

investigated “primary trip length” results from the Vehicle Inventory and Use Survey

database to determine the distribution of trailers in short- and long-haul applications.9 Using a 

primary trip length of 500 miles or less to represent short-haul use, the agencies found that, of 

the reported vehicles, over 50 percent of the 53-feet and longer dry vans were used in longhaul and over 80 percent of the shorter vans were used in short-haul applications. Over 70 

percent of the reported 53-feet and longer refrigerated vans were long-haul trailers, with 65 

percent of the shorter refrigerated vans used in short-haul applications. The survey found that 

0

50000

100000

150000

200000

250000

300000

350000

400000

199619971998199920002001200220032004200520062007200820092010

2011

20122013

Total Factory Shipments

(All Trailer Types)

ACT Research Annual Factory Shipments
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non-box trailers are most frequently used for short-haul. Figure 1-5 summarizes these 

findings.

Figure 1-5 2002 Vehicle Inventory and Use Survey Considering Primary Trip Length for TractorTrailers

Truck drivers and trucking fleets frequently do not control all or even any of the 

trailers that they haul. Trailers can be owned by freight customers, large equipment leasing 

companies, third party logistics companies, and even other trucking companies. Containers 

on chassis, which function as trailers, are rarely owned by truck operators. Rather, they are 

owned or leased by ocean-going shipping companies, port authorities or others. This 

distinction between who hauls the freight and who owns the equipment in which it is hauled 

means that truck owners and operators have limited ability to be selective about the trailers 

they carry, and very little incentive or ability to take steps to reduce the fuel use of trailers that 

they neither own or control.

For refrigerated trailers, the story is slightly different. These trailers are used more 

intensely and accumulate more annual miles than other trailers. Over time, refrigerated 

trailers can also develop problems that interfere with their ability to keep freight temperature -

controlled. For example, the insulating material inside a refrigerated trailer’s walls can 

gradually lose its thermal capabilities due to aging or damage from forklift punctures. The 

door seals on a refrigerated trailer can also become damaged or loose with age, which greatly 

affects the insulation characteristics of the trailer, similar to how the door seal on a home 

refrigerator can reduce the efficiency of that appliance. As a result of age-related problems 

and more intense usage, refrigerated trailers tend to have shorter procurement cycles than dry

van trailers, which means a faster turnover rate, although still not nearly as fast as for trucks in 

their first use.
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Tractor-trailers are often used in conjunction with other modes of transportation (e.g., 

shipping and rail) to move goods across the country, known as intermodal shipping. 

Intermodal traffic typically begins with containers carried on ships, and then they are loaded 

onto railcars, and finally transported to their end destination via truck. Trucks that are used in 

intermodal applications are of two primary types. Trailer-on-flatcar (TOFC) involves lifting 

the entire trailer or the container attached to its chassis onto the railcar. In container-onflatcar (COFC) applications, the container is removed from the chassis and placed directly on 

the railcar. The use of TOFCs allows for faster transition from rail to truck, but is more 

difficult to stack on a vessel; therefore the use of COFCs has been increasing steadily. Both 

applications are used throughout the U.S. with the largest usage found on routes between 

West Coast ports and Chicago, and between Chicago and New York. 

1.2.4 Trailer Fleet Size Relative to the Tractor Fleet

In 2013, over 800,000 trailers were owned by for-hire fleets and almost 300,000 were 

owned by private fleets. Trailers that are purchased by fleets are typically kept much longer 

than are the tractors, so trucks and trailers have different purchasing cycles. Also, many

trailers are owned by shippers or by leasing companies, not by the trucking fleets. Because of 

the disconnect between owners, the trailer owners may not benefit directly from fuel 

consumption and GHG emission reductions.

The industry generally recognizes that the ratio of the number of dry van trailers in the fleet 

relative to the number of tractors is typically three-to-one. 10 Typically at any one time, two 

trailers are parked while one is being transported. Certain private fleets may have ratios as 

high as six-to-one and owner-operators may have a single trailer for their tractor. The ratio of 

refrigerated vans to tractors is closer to two-to-one. This is partly due to the fact that it is 

more expensive to purchase and operate refrigerated vans compared to dry vans. Specialty

trailers, such as tanks and flatbeds are often attached to a single trailer throughout much of 

their life. This characteristic of the trailer fleet impacts the cost effectiveness of trailer 

technologies. The annual savings achieved due to these technologies are proportional to the 

number of miles traveled in a year and the analysis for many of the trailers must account for 

some amount of inactivity, which will reduce the benefits.
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References

1 U.S. EPA and NHTSA, 2011. Regulatory Impact Analysis for the Final Rulemaking to Establish Greenhouse 

Gas Emissions Standards and Fuel Efficiency Standards for Medium and Heavy-Duty Engines and Vehicles. 

EPA-420-R-11-901. Available at: http://www.epa.gov/otaq/climate/documents/420r11901.pdf

2

http://www.ttmanet.org

3

49 CFR 565

4

“Both Sides of Truck Weight, Size Gear Up for Next Battle”. Szakonyi, Mark. February 25, 2014. Available 

at: http://www.joc.com/regulation-policy/transportation-policy/us-transportation-policy. Accessed: August 18, 

2014.

5

“Wabash Shows What a 33-Foot Pup Would Look Like”. Berg, Tom. Heavy-Duty Trucking 

TruckingInfo.com. March 31, 2014. Available at: www.truckinginfo.com/blog/trailertalk/story/2014/03/wabash-shows-what-a-33-foot-pup-would-look-like.aspx. Accessed: September 23, 2014.

6

Per 46 CFR § 340.2. 

7

19 CFR 115.3

8 Dun & Bradstreet. Hoover’s Inc. Online Company Database. Available at: http://www.hoovers.com. 

9 U.S. Census Bureau. 2002 Economic Census – Vehicle Inventory and Use Survey. 2002. Available at: 

https://www.census.gov/prod/ec02/ec02tv-us.pdf

10 TIAX. LLC. “Assessment of Fuel Economy Technologies for Medium- and Heavy-Duty Vehicles,” Final 

Report to the National Academy of Sciences, November 19, 2009. Page 4-49.