improvements to the test procedures for verifying the efficacy of SmartWay-verified devices, trailers, and tires.

Finally, EPA is testing SmartWay idle reduction systems in a full-scale environmental chamber to better understand the energy load demand on the truck cab and explore a performance-based protocol for aero devices.12

EPA is considering inclusion of refrigerated 53+ ft van trailers and twin trailers (twin 28 ft pups) in SmartWay. It is also evaluating adding an “Elite” category for SmartWay trailers that has a higher fuel savings target, such as 10 percent. This could be met by use of multiple aerodynamic devices such as advanced side skirts and an advanced rear fairing (each providing a 5 percent reduction).

California Air Resources Board Regulation

In December 2008, CARB adopted a regulation to reduce GHG emissions from heavy-duty trucks by requiring new and in-use tractors and trailers to utilize aerodynamic designs and devices and LRR tires when operating in California. The regulation specifies that equipment used to comply with CARB’s regulation must be verified through EPA’s SmartWay program. The regulation applies only to 53+ ft van-type trailers (dry and refrigerated) and the Class 7 or 8 sleeper cab tractors that pull them. The regulatory requirements are summarized in Table 6-3.

Several salient points of the regulation are as follows:

  • The regulation applies to the tractor-trailer operator, not the manufacturer of the tractor or trailer.
  • The regulation applies to any affected tractor-trailer operating on a California road—that is, not just to those trucks based or licensed in California. Thus the regulation is expected to affect truck operators and owners based in other states that deliver products to and from California.
  • The regulation requires tractors and trailers of MY 2011 and later to meet SmartWay requirements as follows: All 53+ ft van trailers regardless of what type of tractor is pulling them; all sleeper cab tractors if pulling a 53+ ft van trailer of any MY. In addition, non-sleeper-cab tractors must use LRR tires.

Because the regulation provides several options that can extend the final compliance date beyond 2013, some truck operators may use 2010 and earlier noncomplying trailers until as late as 2019 if certain conditions or interim milestones are met.

TABLE 6-3 Summary of CARB Regulatory Requirements

Type of Tractor and Trailer Requirement and Timing
MY2011-2013 sleeper cab tractor EPA SmartWay-certified.
MY2011-2013 day cab tractor SmartWay-verified low rolling resistance tires.
MY2011-2013 model year 53+ van trailer EPA SmartWay-certified.
Use SmartWay-verified aerodynamic device(s) that have been demonstrated to achieve at least a 5% fuel savings (4% for refrigerated trailers) and use SmartWay-verified LRR tires.
MY2010 and earlier tractors Use SmartWay-verified LRR tires by 1/2013, both sleeper- and non-sleeper-cab tractors.
M 2010 and earlier trailers Use SmartWay-verified device(s) by 1/2013 that have been demonstrated to achieve at least a 5% fuel savings (4% for a refrigerated trailers) and use SmartWay-verified LRR tires by 1/2017.

SOURCE: and Accessed November 18, 2013.

NHTSA and EPA Regulations

As noted in the introduction to Chapter 1, EPA and the National Highway Transportation Safety Board promulgated standards on GHG emissions and fuel consumption in 2011 (EPA and NHTSA, 2011). The two agencies declined at that time to regulate trailers. However, the GHG emissions model (GEM) used to certify engine and vehicle compliance includes the performance of a default van trailer for line-haul trucks. EPA indicates it only has the authority to set requirements for new trailers, whereas the CARB regulation requires existing trailers to install aerodynamic devices and existing tractors and trailers to use LRR tires.13

Methods for Aerodynamic Performance Evaluation

Regulations require reliable means of evaluation or testing to verify compliance. The value of compliance tests depends on ease of use, accuracy and precision of results, replicative fidelity, availability of test facilities, and relevance of the compliance test to real-world applications.

As noted in an earlier section, “Improvements to SmartWay,” both EPA and several users of the current SmartWay test procedures acknowledged inadequacies in the fidelity


12 Sam Waltzer and Cheryl Bynum, U.S. Environmental Protection Agency, “SmartWay Technology Program: Influencing Efficient Freight Movement into the Future,” personal communication to Tom Cackette and Chuck Salter, NRC Committee on Technologies and Approaches to Reducing the Fuel Consumption of Medium- and Heavy-Duty Vehicles, Phase Two, July 24, 2013.

13 William Charmley, U.S. Environmental Protection Agency, personal communication to Tom Cackettte, committee member, August 2013.

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