Skip to main content
U.S. flag

An official website of the United States government

Here’s how you know

Dot gov

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

HTTPS

Secure .gov websites use HTTPS
A lock (LockA locked padlock) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

    • Environmental Topics
    • Air
    • Bed Bugs
    • Cancer
    • Chemicals, Toxics, and Pesticide
    • Emergency Response
    • Environmental Information by Location
    • Health
    • Land, Waste, and Cleanup
    • Lead
    • Mold
    • Radon
    • Research
    • Science Topics
    • Water Topics
    • A-Z Topic Index
    • Laws & Regulations
    • By Business Sector
    • By Topic
    • Compliance
    • Enforcement
    • Laws and Executive Orders
    • Regulations
    • Report a Violation
    • Environmental Violations
    • Fraud, Waste or Abuse
    • About EPA
    • Our Mission and What We Do
    • Headquarters Offices
    • Regional Offices
    • Labs and Research Centers
    • Planning, Budget, and Results
    • Organization Chart
    • EPA History

Breadcrumb

  1. Home
  2. Regulations for Emissions from Vehicles and Engines

Improvements for Heavy-Duty Engine and Vehicle Test Procedures - Final Rulemaking

Improvements for Heavy-Duty Engine and Vehicle Test Procedures - Final Rulemaking
Basic Information
Legal Authorities
  • 42 U.S.C. §7401 - 7671q
Code of Federal Regulations Citations
  • 40 CFR Part 85
  • 40 CFR Part 9
  • 40 CFR Part 59 - 60
  • 40 CFR Part 85 - 94
  • 40 CFR Part 1027 - 1054
  • 40 CFR Part 1060 - 1074
Docket Numbers
  • EPA-HQ-OAR-2019-0307

On this page:

  • Rule Summary
  • Additional Resources

Rule Summary

Related Topic
  • Greenhouse Gas Emissions Model (GEM)
  • Engine Testing Regulations
  • Regulations for Emissions from Nonroad Vehicles and Engines
  • Regulations for Onroad Vehicles and Engines
  • Greenhouse Gas Emissions Model (GEM)

EPA is finalizing changes to the test procedures for heavy-duty engines and vehicles to improve accuracy and reduce testing burden.

EPA is also making other regulatory amendments concerning light-duty vehicles, heavy-duty vehicles, highway motorcycles, locomotives, marine engines, other nonroad engines and vehicles, and stationary engines.

These amendments affect the certification procedures for exhaust emission standards and related requirements. EPA is finalizing similar amendments for evaporative emission standards for nonroad equipment and portable fuel containers.

These amendments would:

  • Streamline the regulations which will reduce industry costs
  • Increase compliance flexibility
  • Harmonize with other requirements
  • Clarify existing requirements
  • Correct errors

Additional Resources

  • Fact Sheet (pdf) (78 KB, December 2020, EPA-420-F-20-051, About PDF)
  • Final Rulemaking (pdf) (41 MB, published June 29, 2021)
  • Response to Comment (pdf) (2.4 MB, December 2020, EPA-420-R-20-026)
  • EPA memo highlighting regulatory changes (PDF) (7 MB, December 2020)
  • Supplemental Notice of Proposed Rulemaking for Improvements for Heavy-Duty Engine and Vehicle Test Procedures
  • Proposed Rule for Improvements for Heavy-Duty Engine and Vehicle Test Procedures, and other Amendments

Regulations for Emissions from Vehicles and Engines

  • Onroad
    • Passenger Vehicles
    • Commercial Trucks & Buses
    • Motorcycles
  • Nonroad
    • Aircraft
    • Heavy Equipment
    • Locomotives
    • Marine
    • Recreational Vehicles
    • Small Equipment & Tools
  • Greenhouse Gas
Contact Us About Regulations for Emissions from Vehicles and Engines
Contact Us to ask a question, provide feedback, or report a problem.
Last updated on March 18, 2025
  • Assistance
  • Spanish
  • Arabic
  • Chinese (simplified)
  • Chinese (traditional)
  • French
  • Haitian Creole
  • Korean
  • Portuguese
  • Russian
  • Tagalog
  • Vietnamese
United States Environmental Protection Agency

Discover.

  • Accessibility Statement
  • Budget & Performance
  • Contracting
  • EPA www Web Snapshot
  • Grants
  • No FEAR Act Data
  • Plain Writing
  • Privacy
  • Privacy and Security Notice

Connect.

  • Data
  • Inspector General
  • Jobs
  • Newsroom
  • Regulations.gov
  • Subscribe
  • USA.gov
  • White House

Ask.

  • Contact EPA
  • EPA Disclaimers
  • Hotlines
  • FOIA Requests
  • Frequent Questions
  • Site Feedback

Follow.