The exhaust emission standards specified in this section apply to trailers based on the effect of trailer designs on the performance of the trailer in conjunction with a tractor; this accounts for the effect of the trailer on the tractor's exhaust emissions, even though trailers themselves have no exhaust emissions.

(a) Standards apply for trailers based on modeling and testing as described in subpart F of this part, as follows:

(1) Different levels of stringency apply for box vans depending on features that may affect aerodynamic performance. You may optionally meet less stringent standards for different trailer types, which we characterize as follows:

(i) For trailers 35 feet or longer, you may designate as “non-aero box vans” those box vans that have a rear lift gate or rear hinged ramp, and at least one of the following side features: Side lift gate, side-mounted pull-out platform, steps for side-door access, a drop-deck design, or belly boxes that occupy at least half the length of both sides of the trailer between the centerline of the landing gear and the leading edge of the front wheels. For trailers less than 35 feet long, you may designate as “non-aero box vans” any refrigerated box vans with at least one of the side features identified for longer trailers.

(ii) You may designate as “partial-aero box vans” those box vans that have at least one of the side features identified in paragraph (a)(1)(i) of this section. Long box vans may also qualify as partial-aero box vans if they have a rear lift gate or rear hinged ramp. Note that this paragraph (a)(1)(ii) does not apply for box vans designated as “non-aero box vans” under paragraph (a)(1)(i) of this section.

(iii) “Full-aero box vans” are box vans that are not designated as non-aero box vans or partial-aero box vans under this paragraph (a)(1).

(2) CO2 standards apply for full-aero box vans as specified in the following table:

(3) CO2 standards apply for partial-aero box vans as specified in the following table:

(4) Non-box trailers and non-aero box vans must meet standards as follows:

(i) Trailers must use automatic tire inflation systems or tire pressure monitoring systems with wheels on all axles.

(ii) Non-box trailers must use tires with a TRRL at or below 5.1 kg/tonne. Through model year 2020, non-box trailers may instead use tires with a TRRL at or below 6.0 kg/tonne.

(iii) Non-aero box vans must use tires with a TRRL at or below 4.7 kg/tonne. Through model year 2020, non-aero box vans may instead use tires with a TRRL at or below 5.1 kg/tonne.

(5) Starting in model year 2027, you may generate or use emission credits for averaging to demonstrate compliance with the standards specified in paragraph (a)(2) of this section as described in subpart H of this part. This requires that you specify a Family Emission Limit (FEL) for CO2 for each vehicle subfamily. The FEL may not be less than the result of the emission calculation in §1037.515. The FEL may not be greater than the appropriate standard for model year 2018 trailers. These FELs serve as the emission standards for the specific vehicle subfamily instead of the standards specified in paragraph (a) of this section. You may not use averaging for non-box trailers, partial-aero box vans, or non-aero box vans that meet standards under paragraph (a)(3) or (a)(4) of this section, and you may not use emission credits for banking or trading for any trailers.

(6) The provisions of §1037.241 specify how to comply with the standards of this section.

(b) No CH4, N2O, or HFC standards apply under this section.

(c) The emission standards of this section apply for a useful life of 10 years.