Regulations and Standards

Below are the Heavy-Duty Highway Diesel regulations and standards. The links will either take you directly to the rulemaking document, if there's only one document, or the link will take you to a page that has the rulemaking document and all the associated documents for that rule.

NOTE: You will need Adobe Acrobat Reader, available as a free download, to view some of the files on this page. See EPA's PDF page to learn more about PDF, and for a link to the free Acrobat Reader.

Regulation of Fuel and Fuel Additives: Alternative Affirmative Defense Requirements for Ultra-low Sulfur Diesel and Gasoline Benzene Technical Amendment (published May 11, 2010)
EPA issued a direct final rule that largely codifies existing guidance for compliance by refiners, importers, distributors and retailers of highway diesel fuel. This rule allows these regulated parties to use an alternative affirmative defense if EPA finds highway diesel fuel samples above the specified sulfur standard at retail facilities. This rule also allows disqualified small refiners to generate gasoline benzene credits.
- Direct Final Rule (PDF) (11 pp, 115K)

For more information about EPA’s regulations for diesel fuel, including regulations for diesel fuel in Alaska & U.S. Territories, and fuel-related technical amendments, please see our Fuels and Fuel Additives page.

2007 Heavy-Duty Highway Rule
- Original Rule
  Clean Diesel Trucks, Buses, and Fuel: Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirements (Final Rule published January 18, 2001)
- Amendments and Related Notices
  - Emergency Vehicle and SCR Maintenance Rule
    This rule contains three parts. First, EPA is issuing a direct final rule with a corresponding proposed rule that allows manufacturers of engines for fire trucks, ambulances, and dedicated nonroad emergency equipment to request modifications to emission control systems so they do not interfere with emergency vehicles’ missions. Second, EPA is proposing to establish minimum maintenance intervals for urea refills with SCR systems for both on-highway and nonroad engines. Third, EPA is proposing short-term relief for general purpose nonroad equipment during emergencies. For more information about EPA’s rules for nonroad engines, visit EPA’s Nonroad Diesel Engines Regulations page.
    There will be a public hearing on June 27, 2012 in Ann Arbor, Michigan, and the comment period will remain open until July 27, 2012. You should consult the Notice of Proposed Rulemaking (PDF) (30 pp, 602K, published June 8, 2012) for information on how to submit comments and register to speak at the hearing. A telephone conference will be available for those who wish to listen to the hearing, but are unable to attend in person. Note: you will not be able to present testimony over the phone. During the hearing, up to 150 callers may join by dialing the following toll-free number: 1-866-299-3188. At the prompt, enter conference code 7342144423 followed by the # sign.
    - Fact Sheet: EPA Grants Relief for Fire Trucks and Ambulances; Proposes SCR Maintenance and Short-Term Relief for Nonroad Equipment (PDF) (4 pp, 560K, EPA420-F-12-025, May 2012)
    - Direct Final Rule (PDF) (19 pp, 603K, published June 8, 2012)
    - Notice of Proposed Rulemaking (PDF) (30 pp, 602K, published June 8, 2012)
  - Notice: Control of Emissions From New Highway Vehicles and Engines: Approval of New Scheduled Maintenance for Selective Catalyst Reduction Technologies (PDF) (4 pp, 60K, published November 9, 2009)
  - Notice: Control of Emissions From New and In-Use Highway Vehicles and Engines: Approval of New Scheduled Maintenance for Diesel Particulate Filters in Certain Applications (3 pp, 97K, published March 7, 2006)
Testing Related Rulemakings and Technical Amendments
- Direct Final Rule (PDF) (9 pp, 215K, published August 30, 2006) adopting technical amendments to the regulations, correcting typographical errors, revising references, removing old provisions, and revising some provisions regarding deterioration factors.
  - Fact Sheet: Highway Heavy-Duty Diesel Engine Regulatory Amendments (PDF) (4 pp, 119K, EPA420-F-06-059, August 2006)
- In-Use Testing for Heavy-Duty Engines and Vehicles (Final Rule published June 14, 2005; Proposed Rule published June 10, 2004)
- Testing Highway and Nonroad Engines and Omnibus Technical Amendments (Final Procedures published July 13, 2005; Proposed Procedures published September 10, 2004)
- Settlement with the Engine Manufacturers Association to propose a manufacturer-run, in-use emissions testing program for heavy-duty diesel trucks and to provide for EPA engine certification guidance (June 2003)
- Direct Final Rule amending the Test Procedures for Heavy-Duty Engines (published September 5, 1997)
- Heavy-Duty Engine Highway Test Procedure Clarifications (52K ZIP WordPerfect) (December 1995) (Free zip software is available at http://www.download.com)
Rulemakings Regarding Nonconformance Penalties
- Interim Final Rule: Nonconformance Penalties for On-Highway Heavy-Duty Diesel Engines (published January 31, 2012)
- Nonconformance Penalties for 2004 and later Model Year Emission Standards for Heavy-Duty Diesel Engines and Heavy-Duty Diesel Vehicles (Final Rule published August 1, 2002; Proposed Rule published January 16, 2002)
- Nonconformance Penalties for 1996 Model Year Emission Standards for Heavy-Duty Vehicles Final Rule (published February 23, 1996) and Direct Final Rule (published February 23, 1996)
Control of Emissions of Air Pollution from 2004 and Later Model Year Heavy-Duty Highway Engines and Vehicles (Final Rule published October 6, 2000; Proposed Rule published October 1999)
Guidance Document to States
- Smoke Opacity Cutpoints to be Used with SAE J1667 In-Use Smoke Test Procedures (PDF)
- SAE Report Reference (PDF)
- Guidance to States on In-Use Smoke Test Procedures (PDF) (EPA420-F-97-053, April 1997)
New Emission Standards for Heavy-Duty Diesel Engines Use in Trucks and Buses (Final Rule published October 1997)
Control of Air Pollution From Heavy-Duty Engines
- Reopening of Public Comment Period for Control of Air Pollution From Heavy-Duty Engines for Advanced Notice of Proposed Rulemaking (published October 1995)
- Control of Air Pollution From Heavy-Duty Engines (Advance Notice of Proposed Rulemaking published August 1995)
Evaporative and Refueling Emission Regulations for Gasoline- and Methanol-Fueled Light-Duty Vehicles and Light-Duty Trucks and Heavy-Duty Vehicles; Technical Amendments (Final Rule published August 1995)
Agency Completion of Study Regarding Heavy-Duty Engine Rebuilding Practices and Availability of Documents (Notice published August 1995)

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