Testing and Measuring Emissions
Vehicle Testing Regulations
EPA has adopted emission standards for motor vehicles and certain kinds of nonroad vehicles and equipment. To show compliance with these emission standards, manufacturers must follow test procedures specified in the Code of Federal Regulations. This page provides links to the appropriate regulatory citations and includes published information related to the test procedures. These links include a general set of instructions and requirements for manufacturers to measure emissions for certifying their vehicles to EPA emission standards.
The test procedures referenced on this page are related to chassis-based exhaust emission standards, and may also include evaporative emission measurement procedures. See Engine Testing Regulations for information on test procedures for measuring exhaust emissions using engine-based test procedures.
The following table shows which test procedures apply for each category:
Code of Federal Register Citation
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The original regulations for part 1066 were adopted in 2011. EPA has amended these regulations in subsequent rulemakings, both to expand the scope of vehicles covered by part 1066 and to improve the procedures. The current part 1066 procedures are available in the electronic Code of Federal Regulations. Note that when we make changes to the part 1066 test procedures, manufacturers that are already subject to testing under part 1066 may take up to 12 months to comply with the new specifications. The following list of final rules includes all the changes we have made to part 1066. For the most recent rules, the description includes the specific dates on which compliance with the regulatory changes become mandatory.
April 28, 2014 Final Rule (PDF) (474 pp, 6.6MB)
This rule included new standards for motor vehicles subject to vehicle-based emission standards and test procedures, and included a wide range of amendments to part 1065. See Tier 3 Final Rule for additional rulemaking documents. These amendments become legally effective June 27, 2014, though they do not become mandatory until June 27, 2015 under §1066.10(c) and §1065.10(c)(6).
June 17, 2013 Direct Final Rule (PDF) (38 pp, 652KB)
This rule included a range of amendments related to heavy-duty greenhouse gas emission standards, including several changes to the test procedures in part 1066. See Heavy-Duty Greenhouse Gas Amendments for additional rulemaking documents. These amendments become legally effective August 16, 2013, though they do not become mandatory until August 16, 2014 under §1066.10(c) and §1065.10(c)(6).
September 15, 2011 Final Rule (PDF) (408 pp, 4.78MB)
This was the initial publication of part 1066. See Heavy-Duty Greenhouse Gas Final Rule for additional rulemaking documents.