DOT, EPA seeking comments on new data related to Phase 2 of greenhouse gas emissions standards

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Updated Mar 2, 2016

New data related to the next round of emissions standards for heavy trucks has prompted the National Highway Traffic Safety Administration and the Environmental Protection Agency to ask for public comments on the new data and information.

Part of Phase II of the Greenhouse Gas Emissions and Fuel Efficiency Standards for Medium- and Heavy-Duty Engines and Vehicles, data that has been added “relating to the potential stringency of the proposed standards includes: powertrain data; additional aerodynamic test data; supplemental test data relating to drive cycles (and frequency thereof) for vocational vehicles; and cycle average mapping data,” the two agencies said in a notice that will be posted in the Federal Register Wednesday.

The agencies are looking for additional comments on certain revised test reports and a revised version of the Greenhouse Gas Emission Model used in developing certain standards and in demonstrating compliance with the standards.

There are 10 new sets of data NHTSA and the EPA are seeking comment on. Summaries of each are below:

  • Greenhouse Gas Emissions Model P2v2.1 – This is a new release of the GEM simulation tool. The agencies say it contains revisions that include fixing bugs identified by commenters, as well as enhancements to improve the efficiency of test results.
  • Default gasoline engine fuel map for use in GEM – Results from EPA-sponsored testing of a heavy-duty gasoline engine were used to develop a new default fuel map “that could be used to develop the final spark-ignited vocational vehicle standards.”
  • Oak Ridge National Laboratory powertrain data – Results from EPA-sponsored testing on two different heavy-duty powertrain configurations.
  • Southwest Research Institute program update on cycle average mapping data – EPA-sponsored testing on two heavy-duty engines with two different horsepower ratings.
  • Final Southwest Research Institute report to NHTSA – A pre-peer review draft of this report was released in June 2015.
  • Supplemental aerodynamic data from EPA testing – EPA conducted additional aero testing using the coastdown, constant speed, wind tunnel and computational fluid dynamics test procedures.
  • Vocational vehicle drive cycle data – The National Renewable Energy Laboratory collaborated with EPA and conducted a vocational vehicle evaluation to determine the final drive cycle weightings for vocational vehicles.
  • Additional discussion of selective enforcement audit and confirmatory testing for aerodynamic parameters – Commenters raised concerns about the proposed audit testing, and this memo provides additional discussion of how the audits could be conducted.
  • Legal memo discussing issues pertaining to trailers, glider vehicles and glider kits under the Clean Air Act – A draft legal memo discussing issues relating to authority under the Clean Air Act for emission standards for trailers and gliders.
  • Public comment from the Specialty Equipment Market Association – This comment addresses how a proposed amendment related to the Clean Air Act’s prohibition of tampering of emission controls.

More information about the new data can be found by searching Docket No. NHTSA-2014-0132 or Docket No. EPA-HQ-OAR-2014-0827 at once the notice is published in the Federal Register Wednesday.