UNITED STATES ENVIRONMENTAL PROTECTION AGENCY

NATIONAL VEHICLE AND FUEL EMISSIONS LABORATORY

2565 PLYMOUTH ROAD

ANN ARBOR, MI 48105-2498

 OFFICE OF

 AIR AND RADIATION

July 15, 2015

MEMORANDUM

SUBJECT: Characteristics of Excluded Trailers in Proposed Phase 2 Trailer Program: Request for 

Clarifying Information About Unique Trailers.

FROM: Tad Wysor, Engineer, Assessment and Standards Division

TO: Greenhouse Gas Emissions Standards and Fuel Efficiency Standards for Medium- and 

Heavy-Duty Engines and Vehicles - Phase 2 - Docket EPA-HQ-OAR-2014-0827

Introduction

This memo specifically requests that trailer manufacturers and other stakeholders provide the agencies 

with information that may confirm and/or improve our understanding of today’s trailer designs and 

equipment, especially during the official public comment period. EPA and NHTSA staff encourage 

trailer manufacturers to provide images and/or detailed descriptions of any trailers or equipment that 

they believe are not, or may not be, clearly accounted for in the descriptions in the Heavy-Duty Phase 2 

proposed rules, as summarized for convenience below. 

The proposed regulatory language excerpted below represents our best understanding to date of the 

physical characteristics at the time of manufacture of trailers that should be totally excluded from the 

program. The associated preamble language also quoted below provides some explanation and context 

for the proposed provisions. 

In addition, we encourage stakeholders to provide images and/or descriptions of any work-performing 

equipment that would partially interfere with the installation or the effectiveness of some aerodynamic 

technologies – and thus that could qualify a trailer for less-stringent requirements (“Partial-Aero” or 

“Non-Aero” designations) – beyond the following features that we identify in the proposed rules:

• Rear features: Rear lift gate or rear hinged ramp.

• Side features: Side lift gate, belly box, side-mounted pull-out platform, steps for side-door 

access, or a drop-deck design. 

Proposed regulatory language in section 1037.5, “Excluded Vehicles”. 

(Emphasis added for language most applicable to trailer manufacturers.)
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§ 1037.5 Excluded vehicles.

Except for the definitions specified in § 1037.801, this part does not apply to the following vehicles:

(a) Vehicles not meeting the definition of “motor vehicle” in § 1037.801.

(b) Vehicles excluded from the definition of “heavy-duty vehicle” in § 1037.801 because of vehicle 

weight, weight rating, and frontal area (such as light-duty vehicles and light-duty trucks).

(c) Vehicles produced in model years before 2014, unless they are certified under § 1037.150. 

(d) Medium-duty passenger vehicles and other vehicles subject to the light-duty greenhouse gas 

standards of 40 CFR part 86. See 40 CFR 86.1818 for greenhouse gas standards that apply for these 

vehicles. An example of such a vehicle would be a vehicle meeting the definition of “heavy-duty 

vehicle” in § 1037.801 and 40 CFR 86.1803, but also meeting the definition of “light truck” in 40 CFR 

86.1818-12(b)(2).

(e) Vehicles subject to the heavy-duty greenhouse gas standards of 40 CFR part 86. See 40 CFR 

86.1819 for greenhouse gas standards that apply for these vehicles. This generally applies for complete 

heavy-duty vehicles at or below 14,000 pounds GVWR. 

(f) Aircraft meeting the definition of “motor vehicle”. For example, this would include certain 

convertible aircraft that can be adjusted to operate on public roads. Standards apply separately to certain 

aircraft engines, as described in 40 CFR part 87.

(g) Trailers meeting one or more of the following characteristics:

(1) Trailers designed specifically for in-field operations in logging or mining.

(2) Trailers designed to operate at low speeds such that they are unsuitable for normal 

highway operation.

(3) Trailers with permanently affixed components designed for heavy construction that allow 

the trailer to perform its primary function while stationary. This would include crane trailers 

and concrete trailers. Trailers would not qualify under this paragraph (g)(3) based on welding 

equipment or other components that are commonly used separate from trailers.

(4) Trailers less than 35 feet long with three axles, and all trailers with four or more axles.

(5) Trailers intended for temporary or permanent residence, office space, or other work space, 

such as campers, mobile homes, and carnival trailers.

(6) Trailers designed specifically to transport livestock.

(7) Trailers built before January 1, 2018.

(8) Note that the definition of trailer in § 1037.801 excludes equipment that serves similar 

purposes but are not intended to be pulled by a tractor. For example, car-hauling equipment 

does not qualify as a trailer under this part if it is designed to be pulled by a heavy-duty vehicle 

with a pintle hook or hitch instead of a fifth wheel.

(h) Where it is unclear, you may ask us to make a determination regarding the exclusions 

identified in this section. We recommend that you make your request before you produce 

the vehicle.

From Preamble Section IV.C.5: Exclusions and Less-Stringent Standards (pp. 40259-10 of the 

July 13, 2015 Federal Register:

“All trailers built before January 1, 2018 are excluded from the Phase 2 trailer program, and from 40 

CFR part 1037 and 49 CFR part 535 in general (see 40 CFR 1037.5(g) and 49 CFR 535.3(e)). 

Furthermore, the proposed regulations do not apply to trailers designed to be drawn by vehicles other 
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than tractors, and those that are coupled to vehicles with pintle hooks or hitches instead of a fifth wheel. 

As stated previously, we are proposing that non-box trailers that are designed for dedicated use with infield operations related to logging and mining be completely excluded from this Phase 2 trailer program. 

The agencies believe that the operational capabilities of trailers designed for these purposes could be 

compromised by the use of aerodynamic devices or tires with lower rolling resistance. Additionally, the 

agencies are proposing to exclude trailers designed for heavy-haul applications and those that are not 

intended for highway use, as follows:

– Trailers shorter than 35 feet in length with three axles, and all trailers with four or more 

axles (including any lift axles)

– Trailers designed to operate at low speeds such that they are unsuitable for normal 

highway operation

– Trailers designed to perform their primary function while stationary

– Trailers intended for temporary or permanent residence, office space, or other work 

space, such as campers, mobile homes, and carnival trailers

– Trailers designed to transport livestock

– Incomplete trailers that are sold to a secondary manufacturer for modification to 

serve a purpose other than transporting freight, such as for offices or storage.” 

(Secondary manufacturers who purchase incomplete trailers and complete their 

construction to serve as trailers are subject to the requirements of 40 CFR 1037.620.)”

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