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Improving Vehicle Fleet, Activity, and Emissions Data for On-Road Mobile Sources Emissions Inventories


September 2011

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Prepared for
Federal Highway Administration

Kanok Boriboonsomsin
George Scora
Guoyuan Wu
Matthew Barth

Center for Environmental Research and Technology
University of California at Riverside


The statements and conclusions in this report are those of the contractor and not necessarily those of the Federal Highway Administration. The mention of commercial products, their source, or their use in connection with material reported herein is not to be construed as actual or implied endorsement of such products.


The authors acknowledge the funding support from the Federal Highway Administration (FHWA)'s Surface Transportation Environment and Planning Cooperative Research Program (STEP). We are grateful for the feedback and assistance received from Karen Perritt, Cecilia Ho, and Michael Claggett of the FHWA.

We also thank the following individuals at various organizations for their assistance: Jeff Long, Erin Tate, and Steven Magbuhat of the California Air Resources Board; Larry Sherwood, Kristal Avila-Ellington, and Zachary Richardson of the California Bureau of Automotive Repair; Donya Heddy and Estrella Coulter of the Nevada Department of Motor Vehicles; Joyce Minzey, Ashok Morey, Rick Chan, and Fareha Zinnurayen of the California Department of Transportation; Karim Yousuf and James Gutierrez of the Nevada Department of Transportation; Taejoo Shin of the Maricopa Association of Governments; Dale Wells of the Colorado Air Pollution Control Division; and Ross Sheckler and Lee Maynus of Calmar Telematics.

Finally, we thank Alexander Vu, Oscar Garcia, Joseph Dean, Daniel Hormozi, Daniel Sandez,Chien Cheng Yeh, Nan-Hsun Han, and several other individuals at the Center for Environmental Research and Technology, University of California Riverside, for their contribution.

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