Matthew Rodriquez 

Secretary for 

Environmental Protection 

June 19, 2014 

Air Resources Board 

Mary D. Nichols, Chairman 

1001 I Street· P.O. Box 2815 

Sacramento, California 95812 • www.arb.ca.gov 

Deborah Jordan, Director 

Air Division, Region 9 

U.S. Environmental Protection Agency 

75 Hawthorne Street 

San Francisco, California 94105 

Dear Ms. Jordan: 

Edmund G. Brown Jr. 

Governor 

On November 21, 2013, the Air Resources Board (ARB or Board) approved revisions to 

California's State Implementation Plan (SIP) for the both the San Joaquin Valley Air 

Basin and the Sacramento Federal Ozone Nonattainment Area. ARB formally 

submitted these SIP revisions to the U. S. Environmental Protection Agency (U.S. EPA) 

on December 20, 2013 and December 31, 2013, respectively. Appendix D of the 

San Joaquin Air Basin Plan and Appendix F-1 of the Sacramento Plan both 

demonstrate compliance with the Vehicle Miles Traveled (VMT) Offset Requirement of 

the Clean Air Act for the 8-hour ozone and 1-hour ozone standards in the San Joaquin 

Valley Air basin, and for the 8-hour ozone standard in the Sacramento Federal Ozone 

Nonattainment area. (Clean Air Act Section 182(d)(1 )(A)). 

As requested by U.S. EPA staff to aid its review of these SIP revisions, ARB is providing 

further information and analysis which support these demonstrations of compliance with 

the VMT Offset Requirement. As was done in Appendices D and F-1 of the respective 

plans, these additional analyses use California's approved motor vehicle emissions 

model, EMFAC 2011. EMFAC calculates emissions from vehicles when they are 

running using trip-based VMT calculated by metropolitan planning organizations (MPO) 

combined with vehicle population data and corresponding emission rates. In addition to 

running emissions, these additional analyses also include emissions from other 

processes associated with vehicle use: starts, hot soaks and running loss emissions. 

How emissions are calculated for these processes as well as running exhaust are 

shown on the attached EMFAC flow chart. The two remaining processes in the chart, 

diurnal and resting emissions only occur when a vehicle is not being used and therefore 

are not included in this additional analysis. 

The emission rate information embedded in EMFAC and used in this analysis reflects 

the aggregate impacts of all California's mobile source control program. A list of the 

The energy challenge facing California is real. Every Californian needs to take immediate action to reduce energy consumption. 

For a list of simple ways you can reduce demand and cut your energy costs, see our website: http://www.arb.ca.gov. 

California Environmental Protection Agency 

Printed on Recycled Paper 
Ms. Deborah Jordan, Director 

June 19, 2014 

Page 2 

mobile source control measures adopted since 1990 were included in the SIP revisions 

as attachments to their respective appendices. This list is comprehensive and not all 

the measures are of equal impact. Of the measures on that list, those most critical to 

achieving the VOC reductions contributing to compliance with the VMT Offset 

Requirement are the Low Emission Vehicle Program, the Low Emission Vehicle 

Program II, the Advanced Clean Cars Program, reformulated gasoline, and Smog 

Check improvements. 

To simplify U.S. EPA's review, we have provided the new information in the same 

format used for the appendices. Also enclosed at the request of U.S. EPA staff are 

output files from EMFAC 2011 for all scenarios used in each of the VMT Offset 

analyses. (Provided on the enclosed COs) 

If you have any questions, please contact me at (916) 322-2739, or have your staff call 

Mr. Jon Taylor, Chief, Transportation Planning Branch at (916) 322-0285. 

Sincerely, 

Lynn Terry 

Deputy Executive Officer 

Attachments 

Enclosure (compact disks (2)) 

cc: See next page. 
Ms. Deborah Jordan, Director 

June 19, 2014 

Page 3 

cc: (with attachments and enclosure) 

Mr. Seyed Sadredin 

Executive Director/Air Pollution Control Officer 

San Joaquin Valley Air Pollution Control District 

1990 East Gettysburg Avenue 

Fresno, California 93726 

Mr. Samir Sheikh 

Director of Strategies and Incentives 

San Joaquin Valley Air Pollution Control District 

1990 East Gettysburg Avenue 

Fresno, California 93726 

Ms. Tanisha Taylor 

San Joaquin Council of Governments 

555 East Weber Avenue 

Stockton, California 95202 

Mr. Larry Green 

Air Pollution Control Officer 

Sacramento Metropolitan Air Quality 

Management District 

777 121

h Street, Third Floor 

Sacramento, California 95814 

Mr. Dave Johnson 

Air Pollution Control Officer 

El Dorado County Air Quality 

Management District 

330 Fairlane Court 

Placerville, California 95667 

Mr. Tom Christofk 

Air Pollution Control Officer 

Placer County Air Pollution Control District 

11 0 Maple Street 

Auburn, California 95603 

Continued next page. 
Ms. Deborah Jordan, Director 

June 19, 2014 

Page4 

cc: (continued) 

Mr. Christopher D. Brown 

Air Pollution Control Officer 

Feather River Air Quality Management District 

1007 Live Oak Blvd, Suite B-3 

Yuba City, California 95991 

Mr. Mat Ehrhardt, P.E. 

Air Pollution Control Officer 

Yolo-Solano Air Quality Management District 

1947 Galileo Court, Suite 103 

Davis, California 95618 

Mr. Mike McKeever 

Executive Director 

Sacramento Area Council of Governments 

1415 L Street, Suite 300 

Sacramento, California 95814 

Mr. Steve Heminger 

Executive Director 

Metropolitan Transportation Commission 

101 Eighth Street 

Oakland, California 94607-5769 

(without attachments or enclosure) 

Mr. Jon Taylor, Chief 

Transportation Planning Branch 

Air Quality Planning and Science Division 
Ms. Deborah Jordan, Director 

June 19, 2014 

Page 5 

bee: (w/out attachments or enclosure) 

Kurt Karperos, AQPS 

Karen Magliano, AQPS 

Sylvia Vanderspek, AQPS 

Nesamani Kalandiyur, AQPS 

Dennis Wade, AQPS 

EO Chron (2 copies) 

AQPSD Chron 

SIP Library 

Assignment #9176/#18567 

X:\VMT Offset Demonstration\DRAFT Sac SJV Transmittal letter VMT Offset 

US EPA.doc 

X:\VMT Offset Demonstration\SJV VMT Offset Doc for EPA March 2014 

Reformated. docx 

X:\VMT Offset Demonstration\DRAFT Sac VMT Offset Doc for EPA 

Reformated.docx 

X:\VMT Offset Demonstration\VMT _offset_EMFAC Flow Chart.docx