Mobile Source Support and Engine Certification

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For assistance with Mobile Source Support and Engine Certification, contact Jim Lyons at or (916) 444-6666 or Alex Marcucci at or (916) 444-6666.

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Trinity Consultants, with Sierra Research, is uniquely qualified to provide a wide range of mobile source testing, modeling, and certification support services, including those described below. 

Customized Vehicle Test Systems

Sierra Research has designed and constructed specialized systems for testing vehicular emissions and air pollution for a wide range of public and private clients.  Sierra also has experience in designing, instrumenting, and/or operating or training others to operate dozens of vehicles to collect on-road emissions and driving pattern data.  Learn more>>   

Dynamometer Tester

Although chassis dynamometers used in vehicle emissions testing employ calibration routines that check the dynamometer's functionality and calibration, the standard calibration checks that are performed do not ensure that the transient or steady-state loads applied by the dynamometer during a test meet response time or loading accuracy requirements.  For example, a dynamometer can pass all of the standard calibration and quality assurance checks, but the response time of the dynamometer may be so poor that there is a large error in loading during transient testing.  The Sierra Research Dynamometer Tester (U.S. Patent 6,601,441) is designed to measure these errors as well as confirm important dynamometer calibration and testing functions, all in a simple, compact, and portable system.  Learn more>>  

Emission Testing Facilities

Sierra has designed, configured, and operated more than a dozen instrumented vehicles for a variety of private and government clients for on-road second-by-second measurement of exhaust emissions, ambient particles and gases, OBDII status via radio-transponder, and accelerometer-based grade measurement.  Sierra has also set up and operated CVS testing facilities in Sacramento, California and Fairbanks, Alaska, and has audited vehicle emission measurement systems for clients in the U.S. as well as Europe and Asia.  We offer for sale a patented chassis dynamometer tester.  Learn more>>   

I/M Lookup Table Software

Under contract to the U.S. Environmental Protection Agency (U.S. EPA), Sierra Research developed both the original Inspection and Maintenance (I/M) Lookup Table and annual updates to the table until U.S. EPA discontinued funding publicly available updates in 2000.  Since then, Sierra developed and licensed the use of proprietary updated lookup tables, the only available lookup table of vehicle emissions and OBDII test parameters for the full range of model year 1973 and newer in-use motor vehicles.  Most U.S. vehicle emissions inspection and maintenance (I/M) programs use the Sierra Research I/M Lookup Table to ensure consistent and proper testing of motor vehicles.  Learn more>>

I/M Support Services

Sierra Research offers a full range of motor vehicle emissions inspection and maintenance (I/M) program support services for both public and private sector clients.  Sierra has provided I/M-related assistance to government agencies and private contractors in nearly 20 North American and international I/M programs, as well as functioning as the U.S. Environmental Protection Agency primary I/M technical support contractor for many years and working with the California Air Resources Board to evaluate and improve the California Smog Check program.  Learn more>>  

Mobile Source Modeling Analysis

Sierra has an extensive history with mobile source emission factor, emission inventory and vehicle simulation models – covering both model development and model application.  Models include the U.S. Environmental Protection Agency's (U.S. EPA's) MOVES, MOBILE, and NONROAD series and the California Air Resources Board's (CARB's) EMFAC and OFFROAD series.  Sierra also develops customized versions of MOVES, MOBILE, NONROAD, and EMFAC to address specific clients’ needs and has adapted and implemented a vehicle simulation model, VEHSIM, for a variety of applications.  Learn more>>    

Vehicle and Engine Certification and In-Use Compliance Support

Sierra has considerable experience in assisting manufacturers in negotiating the complex process of applying for both federal and California emission certification.  Sierra's assistance ranges from reviewing certification materials and data and providing advice all the way to completing all required paperwork/electronic filings for a manufacturer.  Sierra also has extensive experience working with manufacturers to resolve in-use compliance issues with the California Air Resources Board and U.S. EPA.  Learn more>>

For assistance with mobile source testing, modeling, and certification support services, please contact Jim Lyons at (916) 444-6666 or or Alex Marcucci at (916) 444-6666 or