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Regulations for Emissions from Vehicles and Engines
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Improvements for Heavy-Duty Engine and Vehicle Test Procedures - Supplemental Notice of Proposed Rulemaking

Improvements for Heavy-Duty Engine and Vehicle Test Procedures - Supplemental Notice of Proposed Rulemaking
Basic Information
Legal Authorities
  • 42 U.S.C. §7401 - 7671q
Code of Federal Regulations Citations
  • 40 CFR Part 1036
  • 40 CFR Part 1037
Docket Numbers
  • EPA-HQ-OAR-2019-0307

On this page:

  • Rule Summary
  • Additional Resources

Rule Summary

Note: After review in accordance with Klain memo (available here: https://www.whitehouse.gov/briefing-room/presidential-actions/2021/01/20/regulatory-freeze-pending-review/), EPA is re-issuing this action on March 10, 2021 unchanged from the version signed on 12/23/20.
Related Topic
  • Greenhouse Gas Emissions Model (GEM)
  • Engine Testing Regulations
  • Regulations for Emissions from Nonroad Vehicles and Engines
  • Regulations for Onroad Vehicles and Engines

EPA is publishing a supplemental notice of proposed rulemaking (SNPRM) to improve the Greenhouse gas Emissions Model (GEM) compliance tool for heavy-duty vehicles while more closely matching the outputs produced by the original GEM version 3.0 that was used to establish the CO2 standards for Model Years 2021 and later in the 2016 Heavy-duty Phase 2 final rule.

These amendments would:

  • Improve the GEM compliance tool
  • Increase compliance flexibility
  • Include adjustment factors for GEM outputs
  • Clarify existing requirements
  • Correct errors

Additional Resources

  • Fact Sheet (PDF) (2 pp, 82 K, December 2020, EPA-420-F-20-052, About PDF)
  • Notice of Supplemental Proposed Rulemaking (PDF) (6 pp, 349 K, published June 29, 2021, About PDF)
  • Proposed Rule for Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and other Amendments
  • Final Rule for Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and other Amendments
  • Greenhouse Gas Emissions Model (GEM)
  • Regulations for Emissions from Vehicles and Engines Home
  • Onroad
  • Nonroad
  • Greenhouse Gas
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on July 5, 2022
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