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Testing and Measuring Emissions

EPA's National Vehicle and Fuel Emissions Laboratory (NVFEL) is located in Ann Arbor, Michigan near the heart of the U.S. automotive industry. Many corporations have chosen to locate similar emissions testing laboratories near NVFEL and have taken advantage of its role as a standard laboratory against which similar laboratories compare their results. Vehicles, engines and control technologies are evaluated by the NVFEL beginning with their design stages and throughout their useful life-cycle.

Information and files from these pages are frequently requested by various member of the emissions testing community. They are intended to help clarify, but not replace, the guidance of the CFR or other official regulatory guidance. Other Laboratory responsibilities and related activities are further outlined on our NVFEL page.

Engine Testing Regulations
This page provides links to the appropriate regulatory citations and includes published information related to proposed or final rules for changed test procedures. These links include a full set of instructions and requirements for manufacturers certifying their engines to EPA emission standards.
Test Procedures & Methods
This page provides the contact for assistance concerning procedures and work instructions that describe current EPA NVFEL emission and fuel economy testing processes. These methods are used by the EPA NVFEL to perform analysis of fuels and drive-train emissions.
Dynamometer Drive Schedules
Chassis dynamometer driving schedules and shift schedules are used at the EPA NVFEL for vehicle emissions and fuel economy testing.
  • Quick Graphic Review of Driving Schedules
  • EPA Dynamometer Driving Schedules (DDS) - graphics and files
  • California EPA Air Resources Board DDS - graphics and files
  • Economic Commission for Europe DDS - graphics and files
  • Japanese Automobile Standards DDS - graphics and files
  • Shift Schedule Formatting Guidance
Emissions Analysis
The files on this page are sometimes requested by various member of the emissions testing community or are used to help clarify, but not replace, official regulatory guidance and practices.
  • Emissions Sampling and Analysis Background Information
  • Natural Gas Fuel Analysis
  • Sample Emission and Fuel Economy Calculations
  • NOx Humidity Correction Factor Determination
The purpose of the AIGER CRADA is to identify, encourage, evaluate and develop the instrumentation and techniques to accurately and efficiently measure emissions from motor vehicles as required by the Federal Clean Air Act and the California Health and Safety Code. Ultimately, the goal is to ensure that such technologies are commercialized and are readily available to emission testing facilities, programs and personnel worldwide. The strategies employed are based on openness, sharing and teamwork. Efforts of the group are focused on technical challenges rather than on regulatory issues.

For further information or assistance regarding this page, contact Bill Courtois by phone at (734) 214-4352 or by email at courtois.william@epa.gov.

This page is maintained by EPA's Office of Transportation and Air Quality (OTAQ).
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