Heavy Trucks, Buses, and Engines
Heavy Trucks, Buses, and Engines
You will need Adobe Acrobat Reader to view the Adobe PDF files on this page. See EPA's PDF page for more information about getting and using the free Acrobat Reader.
This page presents emission-related information about heavy-duty highway engines, such as those used in trucks and buses. Much of this content is focused on diesel engines, but requirements also apply for gasoline-fueled and other spark-ignition engines. The requirements apply to engines installed in all vehicles with Gross Vehicle Weight Rating above 14,000 pounds, and to some engines installed in vehicles with Gross Vehicle Weight Rating between 8,500 and 14,000 pounds. This page describes the emission standards and related requirements for criteria pollutants -- NOx, HC, CO, and PM. See Greenhouse Gas Standards for requirements that apply for CO2, N2O, and CH4.
- General Information
- Regulations and Related Documents
- Certification Guidance
- Additional Provisions
- Related Diesel Fuel Sulfur Links
- Related Links
General Information
- National Clean Diesel Campaign Publications
- Health Assessment Document for Diesel Engine Exhaust
- How to Maintain or Rebuild Engines Certified to EPA Standards (PDF) (4 pp, 142K, EPA-420-F-12-052, August 2012)
Regulations and Related Documents
- Summary of CI exhaust emission standards, SI exhaust emission standards, and evaporative emission standards
- 2015 Amendments (published February 19, 2015)
- Direct Final Rulemaking (PDF) (48 pp, 1.04MB)
- See “2015 Amendments” for more information.
- 2012 and 2014 Final Rules for SCR Maintenance, Emergency Equipment, and Use of Nonroad Equipment in Emergency Situations (published June 8, 2012 and August 8, 2014)
- Fact Sheet : EPA Sets Standards for Diesel Fluid Systems: Adopts Relief Measures for Nonroad Equipment (PDF) (3 pp, 147K, EPA-420-F-14-017, July 2014)
- Final Rule (PDF) (20 pp, 325K, published August 8, 2014)
- Summary and Analysis of Comments (PDF) (34 pp, 274K, EPA-420-R-14-001, July 2014)
- See the June 2012 Proposed Rule for information supporting the July 2014 Final Rule.
- 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)
- See Nonroad Diesel Engines for more information about similar rulemaking changes for nonroad engines.
- Nonconformance Penalties for On-Highway Heavy-Duty Diesel Engines (published September 5, 2012)
- 2011 Amendments (published September 15, 2011)
- Final Rule (PDF) (409 pp, 4.90MB)
- See Heavy-Duty Greenhouse Gas Rule for more information.
- 2010 Technical Amendments -- In-Use Testing Revisions (published November 8, 2010)
- Direct Final Rule (PDF) (20 pp, 366K)
- See In-use Testing for more information.
- Greenhouse Gas Reporting Rule (published October 30, 2009)
- Final Rule (PDF) (260 pp, 1.40MB)
- See Greenhouse Gas Reporting for more information.
- 2008 Technical Amendments -- Nonroad SI Rule (published October 8, 2008)
- Final Rule (PDF) (343 pp, 3.7MB)
- See Nonroad SI Rule for more information
- 2008 Technical Amendments -- Locomotive-Marine Rule (published June 30, 2008)
- Final Rule (PDF) (255 pp, 2.10MB)
- See Locomotive-Marine Rule for more information
- 2006 Technical Amendments (published August 30, 2006)
- Fact Sheet: Highway Heavy-Duty Diesel Engine Regulatory Amendments (PDF) (9 pp, 215K, EPA-420-F-06-059, August 2006)
- Direct Final Rule (PDF) (9 pp, 219K)
- Procedures for Testing Highway and Nonroad Engines and Omnibus Technical Amendments (published July 13, 2005)
- Fact Sheet: Regulatory Announcement: Changed Test Procedures for Nonroad Engines and Heavy-Duty Highway Engines (PDF) (4 pp, 134K, EPA-420-F-05-036, July 2005)
- Final Rule (PDF) (193 pp, 7.48MB)
- Technical Support Document and Summary and Analysis of Comments (EPA420-R-05-008, June 2005)
- See Proposed Technical Amendments for the proposed rule and supporting documents (published September 10, 2004)
- Final Rule: 2007 and 2010 Model Year Standards (published January 18, 2001)
- Fact Sheet: Heavy-Duty Engine and Vehicle Standards and Highway Diesel Fuel Sulfur Control Requirement (PDF) (4 pp, 120K, EPA-420-F-00-057, December 2000)
- Fact Sheet: Introduction of Cleaner-Burning Diesel Fuel Enables Advanced Pollution Control for Cars, Trucks, and Buses (PDF) (3 pp, 172K, EPA420-F-06-064, October 2006)
- Final Rule (PDF) (192 pp, 1.71MB)
- Regulatory Impact Analysis (PDF) (824 pp, 3.0MB, EPA420-R-00-026, December 2000)
- Technical Support Document: Air Quality Modeling Analyses (PDF) (107 pp, 320K, EPA-420-R-00-028, December 2000)
- Response to Comments (PDF) (706 pp, 1.96MB, EPA420-R-00-027, December 2000)
See Proposed Emission Standards for proposed rule, fact sheets, and regulatory support documents.
Certification Guidance
- Approval of New Scheduled Maintenance for Selective Catalyst Reduction Technologies (PDF) (4 pp, 145K, published November 9, 2009)
- Approval of New Scheduled Maintenance for Diesel Particulate Filters (PDF) (3 pp, 186K, published March 7, 2006)
- Guidance on Reporting and Evaluating Auxiliary Emission Control Devices and the Defeat Device Prohibition of the Clean Air Act (PDF) (36 pp, 13.6MB, VPCD-98-13, October 15, 1998)
Additional Provisions
- Nonconformance penalties
- Greenhouse gas standards
- On-board Diagnostic regulations
- Manufacturer-run In-use Testing
Related Diesel Fuel Sulfur Links
- 2015 Amendments
- Fact sheet: EPA Issues Amendments to Light-duty Tier 3 Vehicle and Fuel Standards and Other Nonroad and Fuel Provisions (PDF) (2 pp, 135K, EPA-420-F-15-005, January 2015)
- Direct Final Rulemaking (PDF) (48 pp, 1.04MB, published February 19, 2015)
- Notice of Proposed Rulemaking (PDF) (13 pp, 302K, published February 19, 2015)
- Partial withdrawal of Direct Final Rulemaking (PDF) (2 pp, 237K, published May 8, 2015) EPA received negative comments on three items in the February 2015 Direct Final Rule; the withdrawal applies only for amendments related to those topics, which are in 40 CFR 80.1453, 80.1616, and 80.1621.
- Modifications to the Transmix Provisions under the Diesel Sulfur Program
- Fact Sheet (PDF) (2 pp, 143K, EPA-420-F-12-081, December 2012)
- Final Rule (PDF) (13 pp, 284K, published December 26, 2012)
- Amendments to the Nonroad and Highway Diesel Fuel Regulations: Direct Final Rule (70 FR 40889, July 15, 2005)
- Revisions to Motor Vehicle Diesel Fuel Sulfur Transition Provisions, and Technical Amendments to the Highway Diesel, Nonroad Diesel, and Tier 2 Gasoline Programs: Direct Final Rule (PDF) (70 FR 70498, 16 pp, 126K, November 22, 2005), and Tier 3 Program: Proposed Rule (PDF) (78 FR 29816, 377 pp, 3.29MB, May 21, 2013)
- Technical Amendments to the Highway and Nonroad Diesel Rules: Direct Final Rule (PDF) (71 FR 25706, 22 pp, 200K, May 1, 2006)
Related Links to EPA information
- Certification Data
- Hardship Exemptions
- Certification Fees
- Test Procedures
- In-use Fuel
- Imports of Vehicles, Engines and Equipment
- Nonroad Diesel Equipment
- National Clean Diesel Campaign
- Clean Schoolbus USA
- SmartWay
