California High-Speed Rail Authority 

San Francisco to San 

Jose Project Section 

Draft General Conformity 

Determination 

April 2022

The environmental review, consultation, and other actions required by applicable 

federal environmental laws for this project are being or have been carried out by 

the State of California pursuant to 23 U.S.C. 327 and a Memorandum of 

Understanding dated July 23, 2019, and executed by the Federal Railroad 

Administration and the State of California. 

Executive Summary

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EXECUTIVE SUMMARY

The California High-Speed Rail (HSR) System, proposed by the California High-Speed Rail 

Authority (Authority), will provide intercity, high-speed service on more than 800 miles of 

guideway throughout California, connecting the major population centers of Sacramento, the San 

Francisco Bay Area (Bay Area), the Central Valley, Los Angeles, the Inland Empire, Orange 

County, and San Diego. The San Francisco to San Jose Project Section (Project Section, or 

Project), which is the focus of this draft General Conformity Determination, is a critical link 

connecting San Francisco to San Jose, which in turn connects to the San Jose to Central Valley 

Wye Project Extent and the Central Valley portion of the HSR system in Merced County, which 

ultimately connects to the portion of the system running north to Merced and south to Fresno and 

Southern California.

1

The General Conformity Rule, as codified in Title 40 Code of Federal Regulations Part 93, 

Subpart B, establishes the process by which federal agencies determine conformance of 

proposed projects that are federally funded or require federal approval with applicable air quality 

standards. This determination must demonstrate that a Project would not cause or contribute to 

new violations of air quality standards, exacerbate existing violations, or interfere with timely 

attainment or required interim emissions reductions towards attainment. 

This draft General Conformity Determination documents the FRA’s finding that the Project

complies with the General Conformity Rule and that it conforms to the purposes of the area’s 

approved State Implementation Plan and is consistent with all applicable requirements. This draft

General Conformity Determination is being issued for public review and comment. The draft 

General Conformity Determination is available on FRA’s docket at https://www.regulations.gov/, 

Docket FRA-2022-0026. Compliance is demonstrated as follows:

• Operations of the Project would result in a reduction of regional emissions of all applicable air

pollutants and would not cause a localized exceedance of an air quality standard.

• While emissions generated during construction of the Project would exceed the General

Conformity thresholds for nitrogen oxides in the San Francisco Bay Area Air Basin, these

emission increases would be offset through an agreement with the Bay Area Air Quality

Management District (BAAQMD). The agreement between the Authority and BAAQMD can 

be found in Appendix A. The Authority has committed to fully offset all construction emissions

(to net zero) for every year of construction in which emissions exceed the General Conformity

thresholds. 

1 As part of its first phase, the California HSR System is planned as seven distinct sections from San Francisco in the

north to Los Angeles and Anaheim in the south. 

Table of Contents

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TABLE OF CONTENTS

EXECUTIVE SUMMARY ...................................................................................................I

1 INTRODUCTION.....................................................................................................1-1

1.1 Regulatory Status of Resource Study Area..................................................1-1

1.2 General Conformity Regulations ..................................................................1-3

2 CALIFORNIA HIGH-SPEED RAIL PROJECT ........................................................2-1

2.1 California High-Speed Rail System ..............................................................2-1

2.2 California High-Speed Rail System—San Francisco to San Jose 

Project Section .............................................................................................2-1

3 AIR QUALITY CONDITIONS IN THE RESOURCE STUDY AREA ........................3-1

3.1 Meteorology and Climate..............................................................................3-1

3.1.1 San Francisco Peninsula ...............................................................3-1

3.1.2 Santa Clara Valley .........................................................................3-1

3.1.3 North Central Coast Air Basin........................................................3-2

3.1.4 San Joaquin Valley Air Basin.........................................................3-2

3.2 Ambient Air Quality in the Resource Study Area..........................................3-2

3.3 Resource Study Area Emissions ..................................................................3-1

3.4 Project Study Area Designations..................................................................3-1

4 RELATIONSHIP TO NEPA.....................................................................................4-1

5 IMPACT AVOIDANCE AND MINIMIZATION FEATURES AND MITIGATION 

MEASURES............................................................................................................5-1

6 REGULATORY PROCEDURES.............................................................................6-1

6.1 Use of Latest Planning Assumptions............................................................6-1

6.2 Use of Latest Emission Estimation Techniques ...........................................6-1

6.3 Major Construction-Phase Activities.............................................................6-2

6.4 Emission Scenarios ......................................................................................6-2

7 APPLICABILITY ANALYSIS ...................................................................................7-1

7.1 Attainment Status of Resource Study Area ..................................................7-1

7.2 Exemptions from General Conformity Requirements ...................................7-2

7.3 Applicability for Project .................................................................................7-2

7.4 De Minimis Emission Rates..........................................................................7-2

8 CONSTRUCTION ACTIVITIES CONSIDERED......................................................8-1

8.1 Models and Methods for Emissions Modeling ..............................................8-1

8.2 Ballast and Subballast Hauling.....................................................................8-3

8.3 Project Design Features ...............................................................................8-3

9 ESTIMATED EMISSION RATES AND COMPARISON TO DE MINIMIS

THRESHOLDS........................................................................................................9-1

10 REGIONAL EFFECTS ..........................................................................................10-1

11 GENERAL CONFORMITY EVALUATION ............................................................11-1

11.1 Conformity Requirements of Proposed Project ..........................................11-1

11.2 Compliance with Conformity Requirements ...............................................11-1

11.3 Consistency with Requirements and Milestones in Applicable State 

Implementation Plan...................................................................................11-2
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11.3.1 Applicable Requirements from U.S. Environmental 

Protection Agency .......................................................................11-3

11.3.2 Applicable Requirements from California Air Resources 

Board ...........................................................................................11-3

11.3.3 Applicable Requirements from Bay Area Air Quality 

Management District....................................................................11-3

11.3.4 Consistency with Applicable Requirements for the California 

High-Speed Rail Authority ...........................................................11-3

12 ESTIMATED EMISSION RATES AND COMPARISON TO DE MINIMIS

THRESHOLDS—CUMULATIVE ANALYSIS........................................................ 12-1

13 REPORTING AND PUBLIC COMMENTS............................................................ 13-1

14 FINDINGS AND CONCLUSIONS......................................................................... 14-1

15 REFERENCES ..................................................................................................... 15-1

Tables

Table 1 Planning Documents Relevant to the Resource Study Area ............................ 1-3

Table 2 Ambient Criteria Pollutant Concentration Data at Air Quality Monitoring 

Stations in the Resource Study Area ....................................................................... 3-2

Table 3 Estimated Annual Average Emissions for the San Francisco Bay Area Air 

Basin (2015 tons per day)........................................................................................ 3-5

Table 4 Federal Attainment Status of the SFBAAB, NCCAB, and SJVAB .................... 7-1

Table 5 De Minimis Rates for Determining Applicability of General Conformity 

Requirements to Federal Actions............................................................................. 7-3

Table 6 San Francisco to San Jose Annual Construction Emissions in the 

SFBAAB (tons per year)1......................................................................................... 9-1

Table 7 San Francisco to San Jose Annual Construction Emissions in the SJVAB 

(tons per year)1........................................................................................................ 9-2

Table 8 Overlapping HSR System Construction Emissions in the San Francisco 

Bay Area Air Basin (tons per year)......................................................................... 12-2

Table 9 Overlapping HSR System Construction Emissions in the San Joaquin 

Valley Air Basin (tons per year).............................................................................. 12-1

Figures

Figure 1 Resource Study Area Air Basins ..................................................................... 1-2

Figure 2 Air Quality Monitoring Stations Nearest to the Project..................................... 3-3

Attachments 

Attachment A: Letter of Agreement with BAAQMD

April 2022 
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ACRONYMS AND ABBREVIATIONS

°F degrees Fahrenheit

AP-42 USEPA’s AP-42 Compilation of Air Pollutant Emission Factors

Authority California High-Speed Rail Authority 

BAAQMD Bay Area Air Quality Management District 

Bay Area San Francisco Bay Area

C.F.R. Code of Federal Regulations 

CAA Clean Air Act 

CalEEMod California Emissions Estimator Model 

CARB California Air Resources Board 

CEQA California Environmental Quality Act 

CO carbon monoxide 

EIR environmental impact report

EIS environmental impact statement

EMFAC2017 EMission FACtors 2017

EMMA Environmental Mitigation Management and Application

FRA Federal Railroad Administration 

GHG greenhouse gas

HSIPR High-Speed Intercity Passenger Rail 

HSR high-speed rail 

I- Interstate 

IAMF impact avoidance and minimization feature

MBARD Monterey Bay Air Resources District

MOU memorandum of understanding 

mph miles per hour

MPO metropolitan planning organization 

NAAQS national ambient air quality standards 

NCCAB North Central Coast Air Basin

NEPA National Environmental Policy Act 

NO2 nitrogen dioxide 

NOX nitrogen oxide 

NZE near-zero emission (vehicle)

O3 ozone

PM particulate matter 

PM10 particulate matter less than or equal to 10 microns in diameter

PM2.5 particulate matter less than or equal to 2.5 microns in diameter 
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Project Section, Project San Francisco to San Jose Project Section 

Prop 1A Proposition 1A

ROD record of decision 

ROG reactive organic gases 

RSA resource study area 

SFBAAB San Francisco Bay Area Air Basin 

SAFE Safer Affordable Fuel-Efficient

SIP State Implementation Plan 

SJVAB San Joaquin Valley Air Basin

SJVAPCD San Joaquin Valley Air Pollution Control District

SO2 sulfur dioxide

SOX sulfur oxide 

tpy tons per year 

SR State Route

U.S.C. United States Code

USEPA U.S. Environmental Protection Agency 

VMT vehicles miles traveled

VOC volatile organic compound

ZE zero emission (vehicle)
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1 INTRODUCTION

This draft General Conformity Determination for the San Francisco to San Jose Project Section

(Project Section, or Project) of the California High-Speed Rail (HSR) System was prepared 

consistent with the implementing regulations of Section 176 of the Clean Air Act (CAA). Section 

176(c)(1) of the CAA prohibits federal agencies from engaging in, supporting, providing financial 

assistance for, licensing, permitting, or approving any activities that do not conform to an 

applicable CAA implementation plan. That applicable plan may be a federal, state, or tribal 

implementation plan. 

The CAA defines nonattainment areas as geographic regions that have been designated as not 

meeting one or more of the national ambient air quality standards (NAAQS). The CAA requires 

that each state prepare a State Implementation Plan (SIP) for each nonattainment area. A

maintenance plan must be prepared for each former nonattainment area that subsequently 

demonstrated compliance with the standards. The SIP is a state’s plan for how it will meet the 

NAAQS by the deadlines established by the CAA. 

The General Conformity Rule is codified in Title 40 Code of Federal Regulations (C.F.R.) Part 93, 

Subpart B, “Determining Conformity of General Federal Actions to State or Federal 

Implementation Plans.” Conformity to an implementation plan means “conformity to an 

implementation plan’s purpose of eliminating or reducing the severity and number of violations of 

the NAAQS and achieving expeditious attainment of such standards; and that such activities will 

not cause or contribute to any new violation of any standard in any area, increase the frequency 

or severity of any existing violation of any standard in any area; or delay timely attainment of any 

standard or any required interim emission reductions or other milestones in any area” (42 U.S.C. 

7506(c)(1)). 40 C.F.R. Part 93 also establishes the process by which federal agencies determine

conformity. This determination must demonstrate that the federal action would not cause or 

contribute to new violations of air quality standards, exacerbate existing violations, or interfere 

with timely attainment or required interim emissions reductions towards attainment. Since the 

Project is receiving federal funds through grants from the Federal Railroad Administration (FRA)

and may also receive safety approvals from the FRA, it is an action that may be subject to the 

General Conformity Rule. 

FRA prepared the draft General Conformity Determination for public review and comment. The 

final General Conformity Determination will be published after the public comment period.

Analysis used for the San Francisco to San Jose Project Section Final Environmental Impact 

Report (EIR)/Environmental Impact Statement (EIS) was also reviewed and, where appropriate, 

integrated into this draft General Conformity Determination.

1.1 Regulatory Status of Resource Study Area

In November 1993, the U.S. Environmental Protection Agency (USEPA) promulgated two sets of 

regulations to implement section 176(c) of the CAA. The final transportation conformity 

regulations address transportation plans, programs, and projects developed, funded, or approved 

under title 23 United States Code (U.S.C.) or the Federal Transit Act, 49 U.S.C. Section 1601 et 

seq. (40 C.F.R. Part 93 Subpart A). These regulations have been revised several times since 

they were first issued. Though the Transportation Conformity regulations do not apply to the

Project (see Section 1.2, General Conformity Regulations), many of the transportation planning 

documents developed under those regulations are helpful in understanding the regional air quality 

and planning status of the resource study area (RSA). The final general conformity regulations 

were approved on November 30, 1993, and revised on April 5, 2010. Because of the federal 

funding and potential safety and other approvals by FRA, the Project is subject to the general 

conformity regulations.

The RSA for the Project is the San Francisco Bay Area Air Basin (SFBAAB). Figure 1 shows the 

Project footprint as it is situated in the air basin. Planning documents for pollutants for which the 

SFBAAB is classified as federal nonattainment or maintenance are developed by the Bay Area 

Air Quality Management District (BAAQMD), and California Air Resources Board (CARB) and 

approved by the USEPA. 
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Sources: Authority 2019a, 2019b; CARB 2012 MARCH 2019

Note: The portion of the RSA corresponding to the truck route in the NCCAB and SJVAB is not shown.

Figure 1 Resource Study Area Air Basins
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Table 1 Planning Documents Relevant to the Resource Study Area

Plan Status

2001 San Francisco Bay Area 

Ozone Attainment Plan for the 

1-Hour National Ozone Standard

In a March 30, 2001, Federal Register notice (66 Fed. Reg. 17379), the 

USEPA proposed to make a finding that the Bay Area has not attained the 

national 1-hour O3 standard. The USEPA proposed partial approval and partial 

disapproval of the 1999 Ozone Attainment Plan. On August 28, 2001, the 

USEPA took final action on its March 2001 notice, triggering a CAA 

requirement that a new plan be submitted within 1 year of the effective date of 

the USEPA’s final action.

The revised 2001 Ozone Attainment Plan included the necessary changes to 

address the USEPA’s disapproval of the prior plan. In addition, to address the 

requirements triggered by the USEPA’s finding of failure to attain, the plan 

included a new emissions inventory and commitments to adopt and implement 

additional control measures to attain the standard by 2006, the attainment 

deadline. It also included additional contingency measures in the event the 

Bay Area did not attain the standard by 2006.

2017 Clean Air Plan Although not a federal planning document, the Bay Area 2017 Spare the Air, 

Cool the Climate (Clean Air Plan) provided a comprehensive plan to improve 

Bay Area air quality and protect public health. The Clean Air Plan defined a 

control strategy that the BAAQMD and its partners is implementing to: (1) 

attain all state and national ambient air quality standards; (2) eliminate 

disparities among Bay Area communities in cancer health risk from toxic air 

contaminants; and (3) reduce GHG emissions to protect the climate.

Sources: BAAQMD 2001, 2017a

BAAQMD = Bay Area Air Quality Management District 

Bay Area = San Francisco Bay Area 

CAA = Clean Air Act

GHG = greenhouse gases

O3 = ozone

SIP = State Implementation Plan

USEPA = U.S. Environmental Protection Agency

1.2 General Conformity Regulations

On November 30, 1993, the USEPA promulgated final General Conformity regulations at 

40 C.F.R. Part 93 Subpart B for all federal activities except highways and transit programs 

covered by Transportation Conformity. The regulations in Subpart B were subsequently amended 

in April 2010. Because the Project requires approval by the FRA will not be funded or require 

approval(s) under Title 23 U.S.C. or the Federal Transit Act, 49 U.S.C. Section 1601 et seq., the 

General Conformity requirements are applicable, rather than Transportation Conformity. In 

general terms, unless a Project is exempt under 40 C.F.R. Section 93.153(c) or is not on the 

agency’s presumed-to-conform list pursuant to 40 C.F.R. Section 93.153(f), a General Conformity 

Determination is required where a federal action in a nonattainment or maintenance area causes 

an increase in the total of direct and indirect emissions of the relevant criteria pollutants and 

precursor pollutants that is equal to or exceeds certain de minimis rates.

During the applicability analysis, the federal agency determines the following:

• Whether the action will occur in a nonattainment or maintenance area

• Whether one or more of the specific exemptions apply to the action

• Whether the federal agency has included the action on its list of presumed-to-conform actions

• Whether the total direct and indirect emissions are below or above the de minimis levels
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• Where a facility has an emissions budget approved by the state or tribe as part of the SIP or 

Tribal Implementation Plan, the federal agency determines whether the emissions from the 

proposed action are within the budget.

The USEPA’s General Conformity Guidance: Questions and Answers (USEPA Guidance)

(USEPA 1994) states that the applicability analysis can be, but is not required to be, completed 

concurrently with any analysis required under the National Environmental Policy Act (NEPA). The

applicability analysis for this Project is described in Chapter 7, Applicability Analysis. If, after the 

applicability analysis, the Federal agency concludes it should conduct a conformity determination, 

it may demonstrate conformity by one or more of several prescribed methods. These methods 

include:

• Demonstrating that the direct and indirect emissions are specifically identified in the relevant 

implementation plan

• Obtaining a written statement from the entity responsible for the implementation plan that the 

total indirect and direct emissions from the action, along with other emissions in the area, will 

not exceed the total implementation plan emission budget

• Fully offsetting the total direct and indirect emissions by reducing emissions of the same 

pollutant in the same nonattainment or maintenance area
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2 CALIFORNIA HIGH-SPEED RAIL PROJECT 

2.1 California High-Speed Rail System

The Authority is responsible for planning, designing, constructing, and operating the HSR

system. Its mandate is to develop an HSR system connecting the state’s major population 

centers and coordinate with the state’s existing transportation network, which includes intercity 

rail and bus lines, regional commuter rail lines, urban rail and bus transit lines, highways, and 

airports.

The HSR system will provide intercity, high-speed service on more than 800 miles of railroad 

throughout California, connecting the major population centers of Sacramento, the San Francisco 

Bay Area (Bay Area), the Central Valley, Los Angeles, the Inland Empire, Orange County, and 

San Diego. It will use state-of-the-art, electrically powered, high-speed, steel-wheel-on-steel-rail 

technology, including contemporary safety, signaling, and automatic train control systems, with 

trains capable of operating up to 220 miles per hour (mph) over a grade-separated, dedicated 

guideway alignment. 

The FRA is responsible for oversight and regulation of railroad safety and implementation of the 

High-Speed Intercity Passenger Rail (HSIPR). As part of the HSIPR Program, the FRA is 

providing partial funding for the environmental analysis and documentation required under NEPA, 

CEQA, and other related environmental laws. Pursuant to U.S. Code Title 23 Section 327, under 

the NEPA Assignment Memorandum of Understanding between the FRA and the State of 

California, effective July 23, 2019, the Authority is the federal lead agency for environmental 

reviews for all Authority Phase 1 and Phase 2 California HSR System projects. The FRA 

performs Clean Air Act Conformity determinations and other federal approvals retained by the 

FRA under the NEPA Assignment Memorandum of Understanding. 

Although the San Francisco to San Jose Project Section of the HSR system is independent of the 

other HSR project sections for purposes of NEPA and CEQA analysis, certain construction 

activities may occur concurrently with construction activities for other project sections within the 

SFBAAB. Therefore, estimates of cumulative emissions, where available, have been presented in 

Chapter 12, Estimated Emission Rates and Comparison to de minimis Thresholds—Cumulative 

Analysis, of this document. These future emissions estimates have been included in this 

document in the interest of full disclosure of future construction emissions that may occur in the 

SFBAAB from other sections of the HSR system; each of these sections will undergo separate 

conformity determinations.

2.2 California High-Speed Rail System—San Francisco to San Jose 

Project Section

The Project Section will provide HSR service between the 4th and King Street Station in San 

Francisco and San Jose Diridon Station in downtown San Jose, with a station in downtown 

Millbrae. It would connect San Francisco to San Jose, where it will also connect to the San Jose 

to Merced Project Section. The San Jose to Merced Project Section alignment will then turn 

eastward to connect to the Central Valley portion of the HSR system at the Central Valley Wye in 

Merced County, which in turn will connect to the portion of the HSR system running north to 

Merced and south to Fresno and Southern California.

The Project Section is designed to allow trains to and from the Bay Area to achieve the 

Proposition 1A (Prop 1A) travel time requirements. Prop 1A requires that the HSR system be 

designed to achieve a nonstop service travel time of 2 hours and 10 minutes between San Jose 

and Los Angeles Union Station, including a 30-minute ride between San Francisco and San Jose
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(Cal. Streets & Highways Code § 2704.09(b)(4)). The Project Section follows existing 

transportation corridors and is designed to achieve travel times consistent with Prop 1A.2

Although the Project Section is defined as the section connecting San Francisco to San Jose, the 

southern-most subsection—the San Jose Diridon Station Approach Subsection—is fully analyzed 

as part of the San Jose to Merced Project Section Final Environmental Impact 

Report/Environmental Impact Statement and corresponding technical reports. While the analysis 

of this subsection has been incorporated into the San Francisco to San Jose Project Section Final 

Environmental Impact Report/Environmental Impact Statement to support a station-to-station 

analysis with logical termini for the San Francisco to San Jose Project Section, emissions and 

concentration results for the San Jose Diridon Station Approach Subsection are not included in 

this Draft General Conformity Determination. Rather, this Draft General Conformity Determination 

encompasses the Project Section from 4th and King Street Station in San Francisco to Scott 

Boulevard in Santa Clara. Refer to the General Conformity Determination for the San Jose to 

Merced Project Section for analysis that includes the San Jose Diridon Station Approach 

Subsection.

The Project corridor between Fourth Street in San Francisco and Scott Boulevard in Santa Clara 

constitutes approximately 43 miles of alignment, which includes blended Caltrain/HSR track and 

systems, and station locations at 4th and King Street Station in San Francisco and Millbrae-San 

Francisco International Airport Station in Millbrae, and a light maintenance facility (LMF) in 

Brisbane. HSR stations at 4th and King Street and Millbrae would support transit-oriented 

development, provide an interface with regional and local mass transit services, and provide 

connectivity from San Francisco to the South Bay and Central Valley highway network.3

The Project comprises the following four subsections:

• San Francisco to South San Francisco—Extends approximately 10 miles from 4th and 

King Street Station in San Francisco to Linden Avenue in South San Francisco.

• San Bruno to San Mateo—Extends approximately 8 miles from Linden Avenue in South San 

Francisco to Ninth Avenue in San Mateo.

• San Mateo to Palo Alto—Extends approximately 16 miles from Ninth Avenue in San Mateo 

to San Antonio Road in Palo Alto.

• Mountain View to Santa Clara—Extends approximately 9 miles from San Antonio Road in 

Palo Alto to Scott Boulevard in Santa Clara.

The Authority has developed two end-to-end alternatives for the Project: Alternative A and 

Alternative B, described in detail in Chapter 2, Alternatives. It is estimated that construction of the 

Project would take approximately 5 years, with initiation of construction in 2021 and completion in 

2025.

4

2 Prop 1A requires that the HSR system be designed to operate on an alignment that follows existing transportation and 

utility corridors to the extent feasible (Cal. Streets & Highways Code § 2704.09(g)).

3 South Bay refers to Santa Clara County.

4 As construction is expected to take place later than these dates, these construction emissions estimates are 

conservative, as future emissions rates will be lower due to the implementation of cleaner and newer equipment.
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3 AIR QUALITY CONDITIONS IN THE RESOURCE STUDY AREA

3.1 Meteorology and Climate

Air quality is affected by the rate and location of pollutant emissions and by meteorological 

conditions that influence movement and dispersal of pollutants in the atmosphere. Atmospheric 

conditions, such as wind speed, wind direction, and air temperature gradients, along with local 

topography, provide the link between air pollutant emissions and local air quality levels.

Local meteorological conditions vary greatly throughout the Bay Area because of topography and 

elevation as well as proximity to local waterbodies. The Project would traverse two unique and 

different meteorological zones in the SFBAAB: the San Francisco Peninsula and the Santa Clara 

Valley. These two areas are described in the following sections, based on information provided by 

the BAAQMD (BAAQMD 2017b).

In addition, trucks associated with disposal of material excavated for construction of the LMF

would use State Route (SR) 152 to Interstate (I-) 5 to access the Kettleman Landfill in Kettleman 

City, CA. A small portion (approximately 0.1 mile) of SR 152 is located in the MBARD. I-5 is 

located in the western portion of the SJVAPCD. The meteorology of the MBARD and SJVAPCD 

is also described below, based on information provided by MBARD (MBUAPCD 2008) and 

SJVAPCD (SJVAPCD 2015).

3.1.1 San Francisco Peninsula

The San Francisco Peninsula region extends from the Golden Gate to northwest of San Jose, 

bounded by the San Francisco Bay on the east, and the Pacific Ocean on the west. The Santa 

Cruz Mountains run up the center of the peninsula, with elevations exceeding 2,000 feet at the 

southern end, decreasing to 500 feet in South San Francisco. Coastal towns experience a high 

incidence of cool, foggy weather in the summer. Cities in the southeastern peninsula experience 

warmer temperatures and fewer foggy days because the marine air layer is blocked by the 

ridgeline to the west. San Francisco lies at the northern end of the peninsula. Because most of 

San Francisco's topography is below 200 feet, marine air flows easily across most of the city, 

making the climate cool and windy. 

At the northern end of the peninsula in San Francisco, pollutant emissions are high, especially 

from motor vehicle congestion. Localized pollutants, such as carbon monoxide (CO), can build up 

in urban canyons. Urban canyons are created when streets divide dense blocks of structures, 

especially skyscrapers, which can inhibit air circulation at the ground level. In most other areas, 

winds are generally fast enough to carry the pollutants away before they can accumulate. Air 

pollution potential is highest along the southeastern portion of the peninsula, where the high 

winds and fog of the marine layer are obstructed, resulting in accumulated concentrations of 

pollutants. Pollutant transport from upwind sites is common. In the southeastern portion of the 

peninsula, air pollutant emissions are relatively high because of motor vehicle traffic as well as 

stationary sources.

3.1.2 Santa Clara Valley

The Santa Clara Valley is bounded by San Francisco Bay to the north and by mountains to the 

east, south, and west. Temperatures are warm on summer days and cool on summer nights, and 

winter temperatures are mild. At the northern end of the valley, mean maximum temperatures are 

79 degrees Fahrenheit (°F) to 82°F during the summer and 55°F to 59°F during the winter, and 

mean minimum temperatures range from 55°F to 59°F in the summer and 39°F to 43°F in the 

winter. Further inland, where the moderating effect of the bay is not as strong, temperature 

extremes are greater. For example, in San Martin, near the southern end of the Santa Clara 

Valley, temperatures can be more than 10°F warmer on summer afternoons and more than 10°F

cooler on winter nights. Higher daytime temperatures can lead to increased ozone formation.

The air pollution potential of the Santa Clara Valley is high. High summer temperatures, stable 

air, and mountains surrounding the valley combine to promote ozone (O3) formation. In addition 

to the many local sources of pollution, O3 precursors from San Francisco, San Mateo, and 
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Alameda Counties are carried by prevailing winds to the Santa Clara Valley. The valley tends to 

channel pollutants to the southeast. On summer days with low-level inversions, O3 can be 

recirculated by southerly drainage flows in the late evening and early morning and by prevailing 

northwesterlies in the afternoon. A similar recirculation pattern occurs in the winter, affecting 

levels of CO and particulate matter (PM). This movement of the air up and down the valley 

significantly increases the effects of pollutants.

3.1.3 North Central Coast Air Basin

The NCCAB comprises Monterey, Santa Cruz, and San Benito Counties. A small portion of the

truck route along SR 152 falls within the NCCAB in San Benito County. The semi-permanent 

high-pressure cell in the eastern Pacific, known as the Pacific High, is the basic controlling factor 

in the climate of the air basin. In the summer, the high-pressure cell is dominant and frequently 

leads to temperature inversions that inhibit air movement. In the fall, weak offshore flows can 

transport pollutants from the Bay Area or Central Valley into the NCCAB, leading to higher levels 

of air pollution. Air quality is generally good in the winter and early spring as the Pacific High 

migrates southward and has less influence on the air basin (MBUAPCD 2008).

3.1.4 San Joaquin Valley Air Basin

The SJVAB contains all of San Joaquin, Stanislaus, Merced, Madera, Fresno, Kings, and Tulare 

Counties, as well as a portion of Kern County. The route that the Project construction trucks 

would travel (SR 152 and I-5) lies in the western portion of the SJVAB. The area has an inland 

Mediterranean climate that is characterized by warm, dry summers and cool winters. Although 

marine air generally flows into the basin from the Delta, the surrounding mountain ranges restrict 

air movement through and out of the valley, leading to frequent temperature inversions and poor 

air quality. Elevated pollutant concentrations are sometimes mediated by precipitation and fog, 

which tends to be greatest in the northern part of the air basin (SJVAPCD 2015). 

3.2 Ambient Air Quality in the Resource Study Area 

The CARB maintains ambient air monitoring stations for criteria pollutants throughout California. 

Three monitoring stations, each in the SFBAAB, and in the vicinity of the Project alternatives, 

were selected for representative ambient monitored data—Arkansas Street (San Francisco), 

Barron Avenue (Redwood City), and Jackson Street (San Jose). Locations of the monitoring 

stations are shown on Figure 2. These are the nearest stations to the Project area that are 

representative of local air quality conditions. These stations monitor CO, O3, nitrogen dioxide 

(NO2), PM smaller than or equal to 10 microns in diameter (PM10), and PM smaller than or equal 

to 2.5 microns in diameter (PM2.5). Table 2 summarizes the results of ambient monitoring at the 

three stations for 3 years of available data. Between 2015 and 2017, measured CO and NO2

concentrations did not exceed any federal or state standards at any of the three monitoring 

locations. However, the state standards for PM10 were exceeded, as was the federal standard for 

24-hour PM2.5. The federal and state O3 standards were exceeded at Redwood City—Barron 

Avenue and San Jose—Jackson Street. The state 24-hour and annual standards for PM10 were 

exceeded at San Francisco—Arkansas Street and San Jose—Jackson Street. The federal 

standard for 24-hour PM2.5 was exceeded at all three sites. The most frequent exceedances 

occurred at San Jose. 
Chapter 3 Air Quality Conditions in the Resource Study Area

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Figure 2 Air Quality Monitoring Stations Nearest to the Project
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3.3 Resource Study Area Emissions 

The CARB maintains an annual emission inventory for each county and air basin in the state. The 

inventory for the SFBAAB is composed of data submitted to CARB by the local air districts plus 

estimates for certain source categories, which are provided by CARB staff. Table 2 summarizes 

the 2015 inventory data for the SFBAAB. Table 3 shows emissions in tons per day, whereas the 

emissions estimates for the Project are shown in tons per year. Mobile source emissions 

represent the majority of volatile organic compounds (VOCs)5, nitrogen oxide (NOX), and CO 

emissions. Area sources represent the majority of PM10 and PM2.5 emissions, and stationary 

sources represent the majority of sulfur dioxide (SO2) emissions. 

3.4 Project Study Area Designations 

Under the federal criteria, the SFBAAB is currently designated as nonattainment for the federal 

O3 and PM2.5 standards, attainment for the federal CO and lead standards, and 

attainment/unclassified for the federal NO2, PM10, and SO2 standards. The NCCAB is designated 

as attainment for the federal CO standards and attainment//unclassified for all other standards. 

The SJVAB is designated as nonattainment for the federal O3 and PM2.5 standards, maintenance 

for the federal PM10 standard, attainment for the federal CO and lead standards, and attainment/

unclassified for the federal NO2 and SO2 standards. 

5 VOCs, as defined by USEPA, are equivalent to reactive organic gases (ROG) as defined by CARB. Because conformity

is a federal process, this document uses the term VOC except when referring to a California-specific requirement.
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Table 2 Ambient Criteria Pollutant Concentration Data at Air Quality Monitoring Stations in the Resource Study Area

Pollutant and Standards

San Francisco—Arkansas Street Redwood City—Barron Avenue San Jose—Jackson Street

2015 2016 2017 2015 2016 2017 2015 2016 2017

Ozone (O3) a

Maximum 1-hour concentration (ppm) 0.085 0.070 0.087 0.086 0.075 0.115 0.094 0.087 0.121

Maximum 8-hour concentration (ppm) 0.067 0.057 0.054 0.071 0.060 0.086 0.081 0.066 0.088

Number of days standard exceeded1

CAAQS 1-hour (>0.09 ppm) 0 0 0 0 0 2 0 0 3

NAAQS 8-hour (>0.070 ppm) 0 0 0 1 0 2 2 0 4

CAAQS 8-hour (>0.070 ppm) 0 0 0 1 0 2 2 0 4

Carbon monoxide (CO) b

Maximum 8-hour concentration (ppm) 1.3 1.1 1.4 1.6 1.1 1.4 1.8 1.4 1.8

Maximum 1-hour concentration (ppm) 1.8 1.7 2.5 3.4 2.2 2.8 2.4 1.9 2.1

Number of days standard exceeded1

NAAQS 8-hour (>9 ppm) 0 0 0 0 0 0 0 0 0

CAAQS 8-hour (>9.0 ppm) 0 0 0 0 0 0 0 0 0

NAAQS 1-hour (>35 ppm) 0 0 0 0 0 0 0 0 0

CAAQS 1-hour (>20 ppm) 0 0 0 0 0 0 0 0 0

Nitrogen dioxide (NO2)

 a

National maximum 1-hour concentration (ppm) 0.0532 0.0507 0.0586 0.0403 0.0396 0.0462 0.0493 0.0511 0.0675

State maximum 1-hour concentration (ppm) 0.070 0.058 0.073 0.047 0.045 0.067 0.049 0.051 0.067

State annual average concentration (ppm) 0.012 0.010 0.011 0.010 0.009 0.010 0.012 0.011 N/A

Number of days standard exceeded

NAAQS 1-hour (98th percentile>0.100 ppm) 0 0 0 0 0 0 0 0 0

CAAQS 1-hour (0.18 ppm) 0 0 0 0 0 0 0 0 0
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Pollutant and Standards

San Francisco—Arkansas Street Redwood City—Barron Avenue San Jose—Jackson Street

2015 2016 2017 2015 2016 2017 2015 2016 2017

Annual standard exceeded?

NAAQS annual (>0.053 ppm) No No No No No No No No No

CAAQS annual (>0.030 ppm) No No No No No No No No No

Particulate matter (PM10)

2, a

National3 maximum 24-hour concentration (μg/m3) 44.7 35.7 75.9

Station does not monitor PM10

58.8 40.0 69.4

National3 second-highest 24-hour concentration (μg/m3) 38.2 27.9 52.7 47.2 35.2 67.3

State4 maximum 24-hour concentration (μg/m3) 47.0 29.0 77.0 58.0 41.0 69.8

State4 second-highest 24-hour concentration (μg/m3) 39.0 28.0 53.0 49.3 37.5 67.6

National annual average concentration (μg/m3) 9.8 8.8 11.0 21.3 17.5 20.7

State annual average concentration (μg/m3)

5 N/A N/A 22.1 21.9 18.3 21.3

Number of days standard exceeded1

NAAQS 24-hour (>150 μg/m3)

6 0 0 0

Station does not monitor PM10

0 0 0

CAAQS 24-hour (>50 μg/m3)

6 N/A N/A 2 3 0 19

Annual standard exceeded?

CAAQS annual (>20 μg/m3) N/A N/A Yes Station does not monitor PM10 Yes no Yes

Particulate matter (PM2.5)

a

National3 maximum 24-hour concentration (μg/m3) 35.4 19.6 49.9 34.6 19.5 60.8 49.4 22.6 49.7

National3 second-highest 24-hour concentration (μg/m3) 34.3 19.3 49.7 26.0 18.4 57.7 37.0 21.8 46.5

State4 maximum 24-hour concentration (μg/m3) 35.4 19.6 49.9 34.6 19.5 60.8 49.4 22.7 49.7

State4 second-highest 24-hour concentration (μg/m3) 34.3 19.3 49.7 26.0 18.4 57.7 37.0 21.8 46.5

National annual average concentration (μg/m3) 7.9 7.5 9.7 6.0 8.3 9.0 9.9 8.3 9.5

State annual average concentration (μg/m3)

5 7.9 N/A 9.7 6.0 N/A 9.1 10.6 8.4 N/A

Number of days standard exceeded1

NAAQS 24-hour (>35 μg/m3) 0 0 7 0 0 6 2 0 6
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Pollutant and Standards

San Francisco—Arkansas Street Redwood City—Barron Avenue San Jose—Jackson Street

2015 2016 2017 2015 2016 2017 2015 2016 2017

Annual standard exceeded?

NAAQS annual (>12.0 μg/m3) No No No No No No No No No

CAAQS annual (>12 μg/m3) No N/A No No N/A No No No No

Sulfur dioxide (SO2)

National maximum 1-hour concentration (μg/m3)

Station does not monitor SO2 Station does not monitor SO2

N/A N/A

State maximum 1-hour concentration (μg/m3) 3.1 1.8 3.6

State maximum 24-hour concentration (μg/m3) 1.1 0.8 1.1

Number of days standard exceeded

NAAQS 1-hour (99th percentile>0.75 ppb [196 μg/m3])

Station does not monitor SO2 Station does not monitor SO2

0 0 0

CAAQS 1-hour (0.25 ppm [655 μg/m3]) 0 0 0

CAAQS 24-hour (0.04 ppm [105 μg/m3]) 0 0 0

Sources: a CARB 2018;

b USEPA 2018a

CAAQS = California ambient air quality standards

μg/m3 = micrograms per cubic meter

NAAQS = national ambient air quality standards

ppb = parts per billion

ppm = parts per million

N/A = not applicable or there was insufficient or no data available to determine the value

> = greater than

1 An exceedance of a standard is not necessarily a violation because of the regulatory definition of a violation.

2 National statistics are based on standard conditions data. In addition, national statistics are based on samplers using federal reference or equivalent methods.

3 State statistics are based on local conditions data.

4Measurements usually are collected every 6 days.

5 State criteria for ensuring that data are sufficiently complete for calculating valid annual averages are more stringent than national criteria.

6Mathematical estimate of how many days’ concentrations would have been measured as higher than the level of the standard had each day been monitored. Values have been rounded. 
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Table 3 Estimated Annual Average Emissions for the San Francisco Bay Area Air Basin (2015 tons per day)

Source Category TOG VOC/ROG CO NOX SOX PM PM10 PM2.5

Stationary Sources

Fuel combustion 18.8 4.2 27.6 33.4 9.4 1.3 1.3 1.3

Waste disposal 193.3 3.2 1.9 1.1 0.5 - - -

Cleaning and surface coatings 38.8 27.3 0 0 0 - - -

Petroleum production and marketing 72.9 15.1 0.9 0.6 2.1 - - -

Industrial processes 13.9 11.4 2.2 4.3 8.8 9.2 4.9 1.6

Total stationary sources 337.7 61.1 32.6 39.6 20.8 10.6 6.3 2.9

Stationary sources percentage of total 58% 26% 3% 15% 89% 5% 5% 7%

Area-Wide Sources

Solvent evaporation 66.5 56.6 - - - - - -

Miscellaneous processes 64.2 15 128.4 16.4 0.5 176.6 96.5 31.7

Total area-wide sources 130.7 71.6 128.4 16.4 0.5 176.6 96.5 31.7

Area-wide sources percentage of total 22% 30% 12% 6% 2% 87% 81% 72%

Mobile Sources

On-road motor vehicles 62.7 57.8 546.8 126.8 1 12.1 11.9 5.6

Other mobile sources 50.4 45.6 399.8 88.8 1.3 4.2 4.1 3.8

Total mobile sources 113.2 103.3 946.6 215.6 2.3 16.3 16 9.4

Mobile sources percentage of total 19% 44% 85% 79% 10% 8% 13% 21%

Grand total (all sources) 581.6 236.1 1,107.5 271.6 23.5 203.4 118.8 44

Source: CARB 2017 

– = not applicable or data not available 

CO = carbon monoxide

NOX = nitrogen oxide

PM = particulate matter

PM10 = particulate matter smaller than or equal to 10 microns in diameter

PM2.5 = particulate matter smaller than or equal to 2.5 microns in diameter

ROG = reactive organic gases

SOX = sulfur oxide

TOG = total organic gases

VOC = volatile organic compounds

California High-Speed Rail Authority
Chapter 4 Relationship to NEPA

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4 RELATIONSHIP TO NEPA

The San Francisco to San Jose Project Section Final EIR/EIS identifies potential adverse and 

beneficial environmental impacts of the Project, identifies measures to mitigate adverse impacts, 

and identifies the Authority’s preferred alternative. The EIR/EIS was prepared to comply with both 

NEPA and CEQA.

The General Conformity regulations establish certain procedural requirements that must be 

followed when preparing a General Conformity evaluation and are similar, but not identical, to 

those for conducting an air quality impact analysis under NEPA regulations. NEPA requires that 

the air quality impacts of the proposed Project’s implementation be analyzed and disclosed. For 

purposes of NEPA, the air quality impacts of the Project were determined by identifying the 

Project’s associated incremental emissions and air pollutant concentrations and comparing them, 

respectively, to emissions thresholds and to the CAAQS and NAAQS. The air quality impacts of 

the Project under future Plus Project conditions were also compared in the Final EIR/EIS to the 

future No Project conditions for NEPA purposes, and they were compared to existing conditions. 

The General Conformity Determination process and general findings are discussed in Sections 

3.3.4.3, Method for Evaluating Impacts under NEPA, 3.3.6.2, Greenhouse Gases, and 3.3.8, 

Impact Summary for NEPA Comparison of Alternatives, of the Final EIR/EIS. 

To appropriately document the identification and offset, where necessary, of the emissions 

resulting from the Project, FRA is issuing this draft General Conformity Determination. Prior to 

issuing a Final General Conformity Determination, the Authority will enter into an agreement with 

the BAAQMD to offset, as necessary, any emissions resulting from the Project through the 

programs described in Section 12.2, Compliance with Conformity Requirements.
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Chapter 5 Impact Avoidance and Minimization Features and Mitigation Measures

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5 IMPACT AVOIDANCE AND MINIMIZATION FEATURES AND

MITIGATION MEASURES

To reduce impacts on the environment, the construction of the Project would include Project

features and mitigation measures to avoid and minimize impacts on air quality. These Project

features and mitigation measures will be included in the Mitigation Monitoring and Enforcement 

Program, which will be issued concurrently with the ROD and will be enforceable commitments 

undertaken by the Authority. Construction of the Project is anticipated to occur through contract. 

The Authority will include all Project features and mitigation measures in the construction 

contract, which will create binding and enforceable commitment to implement them. 

The Authority will be responsible for implementing and overseeing a mitigation monitoring 

program so the contractor meets all air quality design features. Project design features as part of 

the Project and mitigation measures include the following:

AQ-IAMF#1: Fugitive Dust Emissions

During construction, the contractor will employ the following measures to minimize and control 

fugitive dust emissions. The contractor will prepare a fugitive dust control plan for each distinct 

construction segment. At a minimum, the plan will describe how each measure will be employed 

and identify an individual responsible for ensuring implementation. At a minimum, the plan will 

address the following components unless alternative measures are approved by the applicable air 

quality management district:

• Cover all vehicle loads transported on public roads to limit visible dust emissions and

maintain at least 6 inches of freeboard space from the top of the container or truck bed.

• Clean all trucks and equipment before exiting the construction site using an appropriate

cleaning station that does not allow runoff to leave the site or mud to be carried on tires off

the site.

• Water exposed surfaces and unpaved roads at a minimum three times daily with adequate

volume to result in wetting of the top 1 inch of soil but avoiding overland flow. Rain events

may result in adequate wetting of top 1 inch of soil to alleviate the need to manually apply

water.

• Limit vehicle travel speed on unpaved roads to 15 miles per hour (mph).

• Suspend any dust-generating activities when average wind speed exceeds 25 mph.

• Stabilize all disturbed areas, including storage piles that are not being used on a daily basis

for construction purposes, by using water, a chemical stabilizer/suppressant, hydro mulch or

by covering with a tarp or other suitable cover or vegetative ground cover. In areas adjacent

to organic farms, the Authority will use nonchemical means of dust suppression.

• Stabilize all on-site unpaved roads and off-site unpaved access roads using water or a

chemical stabilizer/suppressant, to effectively control fugitive dust emissions. In areas

adjacent to organic farms, the Authority will use nonchemical means of dust suppression.

• Apply water to or presoak all areas where land clearing, grubbing, scraping, excavation, land

leveling, grading, cut and fill, and demolition activities are carried out.

• For buildings up to six stories tall, wet all exterior surfaces of buildings during demolition.

• Limit or expeditiously remove the accumulation of mud or dirt from adjacent public streets at

a minimum of once daily, using a vacuum type sweeper.

• After the addition of materials to or the removal of materials from surface or outdoor storage

piles, apply sufficient water or a chemical stabilizer/suppressant.

• Where feasible, install wind breaks (e.g., dust curtains, plastic tarps, solid fencing) on the

average dominant windward side(s) of station construction areas. For purposes of
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implementation, chain-link fencing with added landscape mesh fabric adequately qualifies as 

solid fencing.

• Post a publicly visible sign with the telephone number and person to contact at the Authority 

regarding dust complaints. This person would respond and take corrective action within 48 

hours. The phone number for the local air district would also be visible to ensure compliance 

with applicable regulations.

AQ-IAMF#2: Selection of Coatings

During construction, the contractor will use:

• Low-volatile organic compound (VOC) paint that contains less than 10 percent of VOC 

contents.

• Super-compliant or Clean Air paint that has a lower VOC content than that required by Bay 

Area Air Quality Management District Regulation 8, Rule 3 when available. If not available, 

the contractor will document the lack of availability, recommend alternative measure(s) to 

comply with Regulation 8, Rule 3, or disclose absence of measure(s) for full compliance, and 

obtain concurrence from the Authority.

AQ-IAMF#3: Renewable Diesel

During construction, the contractor will use renewable diesel fuel to minimize and control exhaust 

emissions from all heavy-duty off-road diesel-fueled construction equipment and on-road diesel 

trucks. Renewable diesel must meet the most recent American Society for Testing and Materials 

(ASTM) specification for diesel with the lowest carbon intensity among petroleum fuels sold in 

California. The contractor will provide the Authority with monthly and annual reports, through the 

Environmental Mitigation Management and Application (EMMA) system, of renewable diesel 

purchase records and equipment and vehicle fuel consumption. Exemptions to use traditional 

diesel can be made where renewable diesel is not available from suppliers within 200 miles of the 

project site. The construction contract must identify the quantity of traditional diesel purchased 

and fully document the availability and price of renewable diesel to meet project demand.

AQ-IAMF#4: Reduce Criteria Exhaust Emissions from Construction Equipment

Prior to issuance of construction contracts, the Authority will incorporate the following construction 

equipment exhaust emissions requirements into the contract specifications:

• All heavy-duty off-road construction diesel equipment used during the construction phase will 

meet Tier 4 engine requirements. 

• A copy of each unit’s certified tier specification and any required California Air Resources 

Board (CARB) or air pollution control district operating permit will be made available to the 

Authority at the time of mobilization of each piece of equipment. 

• The contractor will keep a written record (supported by equipment-hour meters where 

available) of equipment usage during project construction for each piece of equipment. 

• The contractor will provide the Authority with monthly reports of equipment operating hours 

(through the EMMA system) and annual reports documenting compliance.

AQ-IAMF#5: Reduce Criteria Exhaust Emissions from On-Road Construction Equipment

Prior to issuance of construction contracts, the Authority will incorporate the following materialhauling truck fleet mix requirements into the contract specifications:

• All on-road trucks used to haul construction materials, including fill, ballast, rail ties, and steel,

will consist of an average fleet mix of equipment model year 2010 or newer, but no less than 

the average fleet mix for the current calendar year as set forth in the CARB’s EMFAC 2014 

database.
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• The contractor will provide documentation to the Authority of efforts to secure such a fleet

mix.

• The contractor will keep a written record of equipment usage during project construction for

each piece of equipment and provide the Authority with monthly reports of vehicle miles

traveled (through EMMA) and annual reports documenting compliance.

AQ-IAMF#6: Reduce the Potential Impact of Concrete Batch Plants

Prior to construction of any concrete batch plant, the contractor will provide the Authority with a 

technical memorandum documenting consistency with the Authority’s concrete batch plant siting 

criteria and utilization of typical control measures. Concrete batch plants will be sited at least 

1,000 feet from sensitive receptors, including places such as day care centers, hospitals, senior 

care facilities, residences, parks, and other areas where people may congregate. The concrete 

batch plant will implement typical control measures to reduce fugitive dust, such as water sprays, 

enclosures, hoods, curtains, shrouds, movable and telescoping chutes, central dust collection 

systems, and other suitable technology, to reduce emissions to be equivalent to the U.S. 

Environmental Protection Agency AP-42 controlled emission factors for concrete batch plants. 

The contractor will provide to the Authority documentation that each batch plant meets this 

standard during operation.

AQ-MM#1: Construction Emissions Reductions—Requirements for Use of Zero Emission 

and/or Near Zero Emission Vehicles and Off-Road Equipment

This mitigation measure will reduce the impact of construction emissions from project-related onroad vehicles and off-road equipment. 

The Authority and all project construction contractors will require that a minimum of 25 percent, 

with a goal of 100 percent, of all light-duty on-road vehicles (e.g., passenger cars, light-duty 

trucks) associated with the project (e.g., on-site vehicles, contractor vehicles) use zero emission 

(ZE) or near-zero emission (NZE) technology.

The Authority and all project construction contractors will have the goal that a minimum of 25 

percent of all heavy-duty on-road vehicles (e.g., for hauling, material delivery and soil 

import/export) associated with the project use ZE or NZE technology. 

The Authority and all project construction contractors will have the goal that a minimum of 10 

percent of off-road construction equipment use ZE or NZE vehicles. 

If local or state regulations mandate a faster transition to using ZE and/or NZE vehicles at the 

time of construction, the more stringent regulations will be applied. For example, EO N-79-20, 

issued by California Governor Newsom September 23, 2020, currently states the following:

• Light-duty and passenger car sales be 100 percent ZE vehicles by 2035

• Full transition to ZE short haul/drayage trucks by 2035

• Full transition to ZE heavy-duty long-haul trucks, where feasible, by 2045

• Full transition to ZE off-road equipment by 2035, where feasible.

The project will have a goal of surpassing the requirements of these or other future regulations as 

a mitigation measure. 

Because the commercial availability of future electric equipment and vehicles is unknown, 

emissions reductions achieved by AQ-MM#1 cannot currently be quantified or included in the 

analysis.

AQ-MM#2: Offset Project Construction Emissions in the SFBAAB 

Prior to issuance of construction contracts, the Authority will be required to enter into an 

agreement with BAAQMD to reduce ROG/VOC and NOX emissions to the required levels. The 

required levels in the SFBAAB are as follows:
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• For emissions in excess of the General Conformity de minimis thresholds (NOX): net zero.

• For emissions not in excess of General Conformity de minimis thresholds but above the 

BAAQMD’s daily emission thresholds (ROG/VOC and NOX): below the appropriate CEQA 

threshold levels.

The mitigation offset fee amount will be determined at the time of mitigation to fund one or more 

emissions reduction projects within the SFBAAB. The offset fee will be determined by the 

Authority and BAAQMD based on the type of projects that present appropriate emission reduction 

opportunities. These funds may be spent to reduce either VOC or NOX emissions (O3

precursors). Documentation of payment will be provided to the Authority or its designated 

representative.

The agreement will include details regarding the annual calculation of required offsets the 

Authority must achieve, funds to be paid, administrative fee, and the timing of the emissions 

reductions projects. Acceptance of this fee by BAAQMD will serve as an acknowledgment and 

commitment by BAAQMD to undertake the following steps: (1) implement an emissions reduction 

project(s) within a timeframe to be determined based on the type of project(s) selected after 

receipt of the mitigation fee designed to achieve the emissions reduction objectives; and 

(2) provide documentation to the Authority or its designated representative describing the 

project(s) funded by the mitigation fee, including the amount of emissions reduced (tons per year) 

in the SFBAAB from the emissions reduction project(s). To qualify under this mitigation measure, 

the specific emissions reduction project(s) must result in emissions reductions in the SFBAAB 

that are real, surplus, quantifiable, enforceable, and would not otherwise be achieved through 

compliance with existing regulatory requirements or any other legal requirement. Pursuant to 

40 C.F.R. Section 93.163(a), the necessary reductions must be achieved (contracted and 

delivered) by the applicable year in question. Funding will need to be received prior to contracting 

with participants and should allow enough time to receive and process applications to fund and 

implement off-site reduction projects prior to commencement of project activities being reduced. 

This would equate roughly to 1 year prior to the required mitigation; additional lead time may be 

necessary depending on the level of off-site emissions reductions required for a specific year.

This mitigation measure will be effective in offsetting emissions generated during construction of 

the project through the funding of emissions reduction projects. It is BAAQMD’s experience that 

implementation of an agreement is feasible mitigation that effectively achieves actual emissions 

reductions.

This mitigation measure would not be expected to adversely affect air quality in the SFBAAB 

because purchasing emissions offsets would not result in any physical change to the 

environment, and therefore would not result in other secondary environmental impacts. In 

addition to VOC and NOX, emissions reduction projects could reduce other criteria pollutants and 

GHGs. However, this would be a beneficial secondary impact of this mitigation measure and is 

not a required outcome to mitigate any impacts of the project.
Chapter 6 Regulatory Procedures

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6 REGULATORY PROCEDURES 

The General Conformity regulations establish certain procedural requirements that must be 

followed when preparing a General Conformity evaluation. The procedures required for the 

General Conformity evaluation are similar, but not identical, to those for conducting an air quality 

impact analysis pursuant to NEPA regulations. This draft General Conformity Determination is 

being released for public and agency review pursuant to 40 C.F.R. Section 93.156, and the final 

General Conformity Determination would be published after the public comment period.

The Authority identified the appropriate emission estimation techniques and planning 

assumptions in consultation with the state entities charged with regulating air pollution in the 

SFBAAB.

6.1 Use of Latest Planning Assumptions 

The General Conformity regulations require the use of the latest planning assumptions for the 

area encompassing the federal action, derived from the estimates of population, employment, 

travel, and congestion most recently approved by the area’s metropolitan planning organizations 

(MPO) (40 C.F.R. § 93.159(a)). 

The emission estimation techniques, which were slightly different from those used in establishing 

the applicable SIP emissions budgets, have been approved by the BAAQMD. The traffic data 

used in the air quality analysis are based on the level of ridership as presented in Connecting and 

Transforming California, 2016 Business Plan (2016 Business Plan) (Authority 2016). Further, the 

traffic data are consistent with the most recent estimates made by the MPOs for traffic volume 

growth rates, including forecast changes in VMT and vehicle hours traveled. The MPOs

developed these estimates from their traffic assignment models based on current and future 

population, employment, and travel and congestion information. These assumptions are 

consistent with those in the current conformity determinations for the regions’ regional 

transportation plans and transportation improvement programs. 

6.2 Use of Latest Emission Estimation Techniques

The General Conformity regulations require the use of the latest and most accurate emission 

estimation techniques available, unless such techniques are inappropriate (40 C.F.R. § 

93.159(b)). Emissions from construction activities were calculated using a combination of 

emission factors and methodologies from the California Emissions Estimator Model (CalEEMod), 

version 2016.3.2, the CARB’s EMission FACtors 2017 (EMFAC2017) model, and the USEPA’s 

Compilation of Air Pollutant Emission Factors (AP-42) based on Project-specific construction data 

(e.g., schedule, equipment, truck volumes) provided by the Project design team (Scholz 2018, 

2020, 2021). CalEEMod provides the latest emission factors for construction off-road equipment.

It accounts for lower fleet population and growth factors because of the 2007–2009 economic 

recession and updated load factors based on feedback from engine manufacturers. The use of 

emission rates from CalEEMod reflects the recommendation of the CARB to capture the latest 

off-road construction assumptions. CalEEMod default load factors (the ratio of average 

equipment horsepower utilized to maximum equipment horsepower) and useful life parameters 

were used for emission estimates. 

Construction exhaust emissions from equipment; fugitive dust emissions from earthmoving 

activities; and emissions from worker trips, deliveries, and material hauling were calculated and 

compiled in a spreadsheet tool specific to the Project for each year of construction. Mobile source 

emission burdens from worker trips and truck trips were calculated using VMT estimates and 

appropriate emission factors from EMFAC2017. Fugitive dust from re-entrained road dust was 

calculated using emission factors from USEPA’s AP-42, Sections 13.2.1 and 13.2.2. Refer to 

Chapter 8, Construction Activities Considered, for further detail on the emissions estimation 

techniques. Modeled emission rates assume the implementation of all IAMFs (see Chapter 5, 

Impact Avoidance and Minimization Features and Mitigation Measures).
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6.3 Major Construction-Phase Activities 

Project-specific data, including construction equipment lists and the construction schedule, were 

used for the analysis. Calculations were performed for each year of construction for the Project

using default emission factors, as described further in Chapter 8, Construction Activities 

Considered.

Major activities were grouped into the following categories:

• At grade 

• Embankment (berm)

• Stations and LMF

Construction activities associated with each component included demolition, excavation, utilities, 

ballast and trackwork, roadwork, concrete forming, and other rail work. Each of these activities 

was considered to evaluate the regional and localized air quality effects during the construction 

phase. Refer to Chapter 8 for further detail on the construction schedule.

6.4 Emission Scenarios 

The General Conformity regulations require that the evaluation reflect certain emission scenarios 

(40 C.F.R. § 93.159(d)). Specifically, these scenarios generally include the evaluation of direct

and indirect emissions from a proposed project for the following years: (1) for nonattainment 

areas, the attainment year specified in the SIP, or if the SIP does not specify an attainment year, 

the latest attainment year possible under the CAA, and for maintenance areas, the farthest year 

for which emissions are projected in the approved maintenance plan; (2) the year during which 

the total of direct and indirect emissions for the federal action are projected to be the greatest on 

an annual basis; and (3) any year for which the applicable SIP specifies an emissions budget. 

Both the operational and construction phases of the action must be analyzed, and the following 

applies to the Project:

• Emissions generated during the operational phase of the Project would meet the emission 

requirements for the years associated with Items 1 and 3 because the emissions generated 

during the operational phase would be less than those emitted in the No Project scenario. In 

addition, microscale analyses conducted for the EIR/EIS demonstrate that the operational 

phase of the Project would not cause or exacerbate a violation of the NAAQS for all 

applicable pollutants (see Final EIR/EIS, Section 3.3.6.1, Air Quality). 

• Emissions generated during the Project’s construction phase, which would include the year 

with the greatest amount of total direct and indirect emissions (2022, except 2025 for CO 

under Alternative A),6 may be subject to General Conformity regulations because they would 

increase regional emission rates and, as such, have the potential to cause or exacerbate an 

exceedance of the NAAQS. Therefore, analyses were conducted to estimate the amounts of 

emissions that would be generated during each year of the construction phase (for 

comparison with the General Conformity applicability rates) and the potential impacts of these 

emissions on local air quality levels. Emissions generated at the construction sites (e.g., 

tailpipe emissions from the on-site heavy-duty diesel equipment and fugitive dust emissions 

generated by vehicles traveling within the construction sites) and on the area’s roadways by 

vehicles traveling to and from these sites (by vehicles transporting materials and the workers 

traveling to and from work) were considered. 

• Air quality dispersion modeling would be required for this conformity analysis to estimate the 

Project’s localized impacts on PM concentrations if the annual emissions of the pollutants 

generated during construction were to exceed the General Conformity de minimis thresholds. 

6 As construction is expected to take place later than these dates, these construction emissions estimates are 

conservative, as future emissions rates will be lower due to the implementation of cleaner and newer equipment.
Chapter 6 Regulatory Procedures

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Annual emissions were estimated for each year of the Project’s construction period. These 

emissions, which are the maximum values for the Project, are described in more detail in 

Chapter 9, Estimated Emission Rates and Comparison to De Minimis Thresholds, of this report.
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Chapter 7 Applicability Analysis

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7 APPLICABILITY ANALYSIS 

The first step in a General Conformity evaluation is an analysis of whether the requirements apply 

to a proposed federal action in a nonattainment or a maintenance area. Unless exempted by the 

regulations or otherwise presumed to conform, a Federal action requires a General Conformity 

Determination for each pollutant where the total of direct and indirect emissions caused by the 

federal action would equal or exceed an annual de minimis emission rate. 

7.1 Attainment Status of Resource Study Area

The USEPA designates each county (or portions of counties) within California as attainment, 

maintenance, or nonattainment based on the area's ability to meet the NAAQS. Areas are 

designated as attainment if ambient air concentrations of a criteria pollutant are below the 

ambient standards. Areas are designated as nonattainment if ambient air concentrations are 

above the ambient standards. Areas previously designated as nonattainment that subsequently 

demonstrated compliance with the standards are designated as maintenance. Table 4 

summarizes the attainment status of the SFBAAB, NCCAB, and SJVAB with regard to the 

NAAQS. 

Table 4 Federal Attainment Status of the SFBAAB, NCCAB, and SJVAB

Pollutant SFBAAB NCCAB SJVAB

O3 Marginal Nonattainment Attainment Extreme Nonattainment

PM10 Attainment Attainment Maintenance

PM2.5 Moderate Nonattainment Attainment Serious/Moderate Nonattainment1

CO Attainment Attainment Attainment

NO2 Attainment Attainment Attainment

SO2 Attainment Attainment Attainment

Source: USEPA 2018b

CO = carbon monoxide 

NCCAB = North Central Coast Air Basin 

NO2 = nitrogen dioxide

O3 = ozone

PM10 = particulate matter smaller than or equal to 10 microns in diameter 

PM2.5 = particulate matter smaller than or equal to 2.5 microns in diameter 

SFBAAB = San Francisco Bay Area Air Basin

SJVAB = San Joaquin Valley Air BasinSO2 = sulfur dioxide

1 The SJVAB is designated serious nonattainment for the 1997 and 2006 PM2.5 standards and moderate nonattainment for the 2012 PM2.5 standard. 

The SFBAAB is currently designated as marginal nonattainment for 8-hour O3

7 (2008 and 2015 

standards) and moderate nonattainment for PM2.5 (2006 standard). The SJVAB is designated as 

extreme nonattainment for 8-hour O3 (2008 and 2015 standards), serious nonattainment for PM2.5

(1997 and 2006 standards), moderate nonattainment for PM2.5 (2012 standard), and maintenance 

for PM10 (1987 standard). As such, the FRA is required to demonstrate Project-level compliance 

with the General Conformity Rule for NOX and VOCs (O3 and PM2.5 precursors), PM2.5, PM10, SO2

(PM2.5 precursor), and ammonia8 (PM2.5 precursor) if the total of direct and indirect emissions of 

these pollutants caused by the Project in the SFBAAB or SJVAB would exceed the General 

Conformity de minimis thresholds.

7 Because O3 is a secondary pollutant (i.e., it is not emitted directly into the atmosphere, but is formed in the atmosphere

from the photochemical reactions of VOCs and NOX in the presence of sunlight), its de minimis threshold is based on 

primary emissions of its precursor pollutants, NOX and VOCs. If the net emissions of either NOX or VOCs exceed the de 

minimis applicability thresholds (USEPA 1994), the federal action is subject to a general conformity evaluation for O3.

8Neither construction nor operation of the project would result in material emissions of ammonia, so no further discussion

of ammonia emissions is provided in this General Conformity Determination. 
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As shown in Table 4, the portion of the RSA in the NCCAB is in attainment for all criteria 

pollutants. As outlined in Section III.A of the General Conformity Rule, “only actions which cause 

emissions in designated nonattainment and maintenance areas are subject to the regulations.” As 

such, a General Conformity analysis is not required for the portion of the Project within the 

NCCAB. There are no applicable de minimis thresholds, and no further discussion of Project

activities in the NCCAB is provided in this General Conformity Determination. 

7.2 Exemptions from General Conformity Requirements 

The General Conformity requirements apply if the net Project emissions equal or exceed certain 

de minimis emission rates. The only exceptions to this applicability criterion are if the activity is on 

the federal agency’s presumed-to-conform list (40 C.F.R. § 93.153(f)), meets the narrow 

exemption in response to an emergency or disaster (40 C.F.R. § 93.153(e)), or is one of the

following topical exemptions:

• Actions that would result in no emissions increase or an increase in emissions that is clearly 

below the de minimis levels (40 C.F.R. § 93.153(c)(2)). Examples include administrative 

actions and routine maintenance and repair. 

• Actions where the emissions are not reasonably foreseeable (40 C.F.R. § 93.153(c)(3))

• Actions which implement a decision to conduct or carry out a conforming program (40 C.F.R.

§ 93.153 (c)(4))

• Actions which include major new or modified sources requiring a permit under the New 

Source Review program (40 C.F.R. § 93.153(d)(1))

• Actions in response to emergencies or natural disasters (40 C.F.R. § 93.153(d)(2))

• Actions which include air quality research not harming the environment (40 C.F.R. § 

93.153(d)(3))

• Actions which include modifications to existing sources to enable compliance with applicable 

environmental requirements (40 C.F.R. § 93.153(d)(4))

• Actions which include emissions from remedial measures carried out under the 

Comprehensive Environmental Response, Compensation and Liability Act that comply with 

other applicable requirements (40 C.F.R. § 93.153(d)(5))

The Project does not meet any of these exempt categories. In addition, the FRA has not 

established a presumed-to-conform list of activities at the time of this evaluation, and the Project

does not meet the requirements of 40 C.F.R. Section 93.153(e). 

7.3 Applicability for Project

After determining that the Project is not otherwise exempt, the applicability of the General 

Conformity requirements to the Project is evaluated by comparing the total of direct and indirect 

emissions for the calendar year of greatest emissions to the General Conformity de minimis

thresholds. Where the total of direct and indirect emissions attributable to the Project is found to 

be below the de minimis emission rates for a pollutant, that pollutant is excluded from General 

Conformity requirements, and no further analysis is required. However, when the emissions of an 

applicable pollutant are at or above a de minimis threshold, that pollutant must undergo a General 

Conformity evaluation.

7.4 De Minimis Emission Rates 

The General Conformity requirements would apply to the federal action for each pollutant for 

which the total of direct and indirect emissions caused by the Project equal or exceed the de 

minimis emission rates shown in Table 5. These emission rates are expressed in units of tons per 

year (tpy) in each air basin for the calendar year. The applicable threshold levels for the pollutants 

for which General Conformity is required in the RSA are shown in Table 5.
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Table 5 De Minimis Rates for Determining Applicability of General Conformity 

Requirements to Federal Actions

Air Basin

Annual Air Pollutant Emissions in Tons per Year

VOC NOX CO PM10 PM2.5 SO2

San Francisco Bay Area Air Basin1 100 100 None None 100 100

San Joaquin Valley Air Basin2 10 10 None 100 70 70

North Central Coast Air Basin3 None None None None None None

Source: 40 C.F.R. § 93.153(b)

CO = carbon monoxide 

NAAQS = national ambient air quality standards 

NOX = nitrogen oxide

O3 = ozone 

PM2.5 = particulate matter smaller than or equal to 2.5 microns in diameter 

PM10 = particulate matter smaller than or equal to 10 microns in diameter 

RSA = resource study area 

SFBAAB = San Francisco Bay Area Air Basin 

SJVAB = San Joaquin Valley Air Basin 

SO2 = sulfur dioxide 

VOC = volatile organic compounds 

1 The General Conformity de minimis thresholds for criteria pollutants are based on the federal attainment status of the SFBAAB. The SFBAAB is 

designated a marginal nonattainment area for the O3 NAAQS and a moderate nonattainment area for the PM2.5 NAAQS. Although the SFBAAB is in 

attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de minimis thresholds are used. 

2 The General Conformity de minimis thresholds for criteria pollutants are based on the federal attainment status of the SJVAB. The SJVAB is 

designated an extreme nonattainment area for the O3 NAAQS, a serious/moderate nonattainment area for the PM2.5 NAAQS, and a maintenance 

area for the PM10 NAAQS. Although the SJVAB is in attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de 

minimis thresholds are used. For PM2.5 and SO2, the de minimis threshold for projects located in serious nonattainment areas (70 tons per year) is 

used because this threshold is lower than the 100 tons per year threshold for projects exclusively in moderate nonattainment areas. For NOx and 

VOCs, the O3 precursor threshold for extreme nonattainment areas (10 tons per year) is used because this threshold is lower than the PM2.5

precursor threshold for serious nonattainment areas (70 tons per year).

3 The NCCAB is in attainment for all criteria pollutants (see Table 4). 
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Chapter 8 Construction Activities Considered

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8 CONSTRUCTION ACTIVITIES CONSIDERED

As shown in Section 3.3.6.2, Air Quality, of the Final EIR/EIS, the results of the regional analyses 

conducted for the Project demonstrate that emissions generated during the operational phase 

would be less than those emitted in the No Project and existing conditions scenarios and the 

microscale analyses demonstrate that the Project would not cause or exacerbate a violation of 

the NAAQS for these pollutants. As such, no further analysis of the operational period emissions

is necessary for this General Conformity Determination. This section focuses on the emissions 

generated from the construction emissions for the Project.

The analysis conducted for the Final EIR/EIS to estimate potential air quality impacts caused by 

on-site (e.g., demolition activities, construction equipment operations, and truck movements) and 

off-site (e.g., worker commuting and truck trips) construction-phase activities included the 

following:

• Estimation of emissions generated by the construction activities (e.g., demolition, trackwork,

concrete and steel construction), including fugitive dust emissions and emissions released

from diesel-powered equipment and trucks based on the hours of operation of each piece of

equipment9

• Identification of heavily traveled truck routes to estimate the cumulative effects of on-site

construction activity emissions and off-site traffic emissions

• An on-site dispersion modeling analysis of the major construction areas

• An off-site dispersion modeling analysis of the roadway intersections and interchanges

adjacent to the construction areas, using traffic data that included construction-related

vehicles and background traffic

• A comparison of the on-site and off-site modeling results to the applicable NAAQS for the

applicable pollutants

Emission rates for these activities were estimated based on the following:

• The number of hours per day and duration of each construction activity

• The number and type of construction equipment to be used

• Horsepower and utilization rates (hours per day) for each piece of equipment

• The quantities of construction/demolition material produced and removed from each site

• The number of truck trips needed to remove construction and demolition material and to bring

the supply materials to each site

The following is a discussion of the construction analysis methodology. A full list of assumptions 

can be found in Appendix C to the San Francisco to San Jose Project Section Air Quality and 

Greenhouse Gases Technical Report (Authority 2019c).

8.1 Models and Methods for Emissions Modeling 

Construction of the Project would generate emissions of VOC, NOX, CO, sulfur oxides (SOX),

PM10, and PM2.5. Emissions would originate from off-road equipment exhaust, employee and haul 

truck vehicle exhaust (on-road vehicles), site grading and earth movement, concrete batching, 

demolition, paving, and architectural coating. These emissions would be temporary (i.e., limited to 

the construction period) and would cease when construction activities are complete. 

9 It is possible changes in VMT, speeds, or idle times resulting from traffic detours during construction could result in

additional emissions. However, it is unknown to what extent motorists will change their driving patterns as a result of traffic 

detours and impediments, and, as such, it would be speculative to quantify the impact of temporary roadway restrictions 

on criteria pollutant emissions. 
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Combustion exhaust, fugitive dust (PM10 and PM2.5), and fugitive off-gassing (VOCs) were 

estimated using a combination of emission factors and methodologies from CalEEMod, version 

2016.3.2; the CARB’s EMFAC2017 model, and the USEPA’s AP-42 Compilation of Air Pollutant 

Emission Factors based on Project-specific construction data (e.g., schedule, equipment, truck 

volumes) provided by the Project design team (Scholz 2018, 2020, 2021).

• Off-road equipment—Emission factors for off-road construction equipment (e.g., loaders, 

graders, bulldozers) were obtained from the CalEEMod (version 2016.3.2) User’s Guide 

appendix, which provides values per unit of activity (in grams per horsepower-hour) by 

calendar year (CAPCOA 2017). Analysts estimated criteria pollutants by multiplying the 

CalEEMod emission factors by the equipment inventory provided by the Project engineering 

team (Scholz 2018, 2020, 2021).

• On-road vehicles—On-road vehicles (e.g., pickup trucks, flatbed trucks) would be required 

for material and equipment hauling, on-site crew and material movement, and employee 

commuting. The analysis estimated exhaust emissions from on-road vehicles using the 

EMFAC2017 emissions model and activity data (miles traveled per day) provided by the 

Project engineering team (Scholz 2018, 2020, 2021). Emission factors for haul trucks are 

based on aggregated-speed emission rates for EMFAC’s T7 Single vehicle category. Factors 

for on-site dump, water, boom, and concrete trucks were based on 5-mph emission rates for 

the T6 Heavy category. Factors for employee commute vehicles were based on a weighted 

average for all vehicle speeds for EMFAC’s light-duty automobile/light-duty truck vehicle 

categories. CARB’s (2019) Safer Affordable Fuel-Efficient (SAFE) Vehicles Rule adjustment 

factors were applied to the emission factors for gasoline-powered vehicles.

10 Fugitive reentrained road dust emissions were estimated using the USEPA’s Compilation of Air 

Pollutant Emission Factors (AP-42), Sections 13.2.1 and 13.2.2 (USEPA 2006, 2011).

• Site grading and earth movement—Fugitive dust emissions from earth movement (e.g., 

site grading, bulldozing, and truck loading) were quantified using emission factors from 

CalEEMod and USEPA (1998) AP-42. Data on the total graded acreage and quantity of cutand-fill material were provided by the Project engineering team (Scholz 2018, 2020, 2021).

• Concrete batching—Fugitive dust emissions from concrete batching at temporary batch 

plants were quantified using emission factors from the BAAQMD’s (2016) Permit Handbook 

and USEPA’s AP-42. Daily and annual batch quantities (cubic yards) were provided by the 

Project engineering team (Scholz 2018, 2020, 2021). 

• Demolition—Fugitive dust emissions from building demolition were based on the anticipated 

amount of square feet to be demolished and calculation method from the CalEEMod User’s 

Guide (CAPCOA 2017).

• Paving—Fugitive VOC emissions associated with paving were calculated using activity data

(e.g., square feet paved) provided by the Project engineer and the CalEEMod default 

emission factor of 2.62 pounds of VOC per acre paved (Scholz 2018; CAPCOA 2017).

• Architectural coating—Fugitive VOC emissions associated with architectural coatings of the 

stations and LMF were calculated using activity data (e.g., square feet coated) provided by 

the Project engineering team and methods contained in the CalEEMod User’s Guide (Scholz

2018; CAPCOA 2017). Emissions calculations assume a VOC content of 150 grams per liter, 

consistent with the BAAQMD’s Regulation 8, Rule 3, Section 301.

10 On May 12, 2021, NHTSA issued a notice of proposed rulemaking to repeal the One National Program Rule (86 Fed 

Reg 25980). This repeal would reverse the effects of the SAFE Rule on light-duty vehicle emission rates.. As of October 

30,, 2021 NHTSA has not issued a final rule.
Chapter 8 Construction Activities Considered

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San Francisco to San Jose Project Section Draft General Conformity Determination Page | 8-3

8.2 Ballast and Subballast Hauling

Ballast and subballast materials could be transported from multiple quarry locations throughout 

Northern California. Analysts estimated emissions from ballast and subballast material hauling by 

trucks and locomotives based on the travel distances and transportation method (by rail or by 

truck) from the locations where ballast materials would be available. Analysts used heavy-duty 

truck emission factors (T7 Single) from EMFAC2017 to estimate emissions from haul trucks and 

rail emission factors from the USEPA (2009) to estimate the locomotive emissions. 

Analysts identified up to five potential quarries that could provide ballast material. All quarries are 

within the SFBAAB, with the farthest quarry located 68 highway miles from the Project footprint.

Ballast and subballast quantities for the Project were provided by the Project engineering team 

and distributed equally among the identified quarries (Scholz 2018). Analysts estimated 

emissions under two hauling scenarios: Scenario 1 assumed ballast and subballast would be 

hauled to the Project footprint using a combination of trucks and locomotives, and Scenario 2 

assumed ballast and subballast would be hauled to the Project footprint using only trucks.

8.3 Project Design Features 

The Authority has developed impact avoidance and minimization features (IAMFs) that would 

avoid or minimize potential air quality effects. Because IAMFs are included as part of the Project

design, they are not considered mitigation, and are included as part of the Project construction 

emissions estimate. Specifically, the following emissions benefits achieved by AQ-IAMF#1 

through AQ-IAMF#5 were assumed in the modeling11. 

• Fugitive dust reductions from earthmoving best management practices (AQ-IAMF#1)

– PM from ground disturbance (e.g., scraping and grading activities), 75 percent (BAAQMD

2017a)

– PM from unpaved vehicle travel (i.e., re-entrained road dust), 75 percent12

– PM from demolition, 36 percent (Countess Environmental 2006)

• VOC reductions of 93 percent from application of architectural coatings (AQ-IAMF#2)13

• PM reductions of 30 percent and greenhouse gas (GHG) reductions from use of renewable

diesel (AQ-IAMF#3) in all off-road diesel-powered engines (Lovegrove and Tadross 2017)

• Criteria pollutant and GHG reductions from use of Tier 4 off-road engines (AQ-IAMF#4).

Emissions reductions vary by pollutant and equipment type. Emissions were modeled using

Tier 4 emission rates from CalEEMod.

• Criteria pollutant and GHG reductions from use of model year 2010 or newer on-road engines

in heavy-duty, diesel powered trucks (AQ-IAMF#5). Emissions reductions vary by pollutant,

analysis year, and air basin. Emissions were modeled using emission rates for model year

2010 or newer engines derived from the CARB’s EMFAC2017 model. The emission rates for

model year 2010 and newer engines reflect implementation of USEPA’s December 2000

Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards

and Highway Diesel Fuel Sulfur Control Requirements.

11 Although the Authority would also comply with AQ-IAMF#6, it was not assumed in the modeling because no new

concrete batch plants would be required for construction of the Project Section.

12 Among other controls, this IAMF requires watering unpaved roads three times daily and limiting vehicle speeds. The 75

percent efficacy is based on a 55 percent reduction for watering and a 44 percent reduction for vehicle speed limits (1-

(.55*.44)) = 0.75 (Countess Environmental 2006). 

13 Assumes an uncontrolled ROG content of 150 grams per liter per BAAQMD Regulation 8, Rule 3, Section 301 and a

controlled ROG content of 10 grams per liter per AQ-IAMF#2.
Chapter 8 Construction Activities Considered

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Chapter 9 Estimated Emission Rates and Comparison

to De Minimis Thresholds

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9 ESTIMATED EMISSION RATES AND COMPARISON

TO DE MINIMIS THRESHOLDS

As discussed in Section 7.3, Major Construction-Phase Activities, three components—at-grade,

embankment (berm), and stations and LMF—would be constructed, depending on the subsection 

and alternative. Each component would be constructed over multiple phases between 2021 and 

2025. 

Total annual estimated emissions generated within the SFBAAB and the SJVAB during the 

construction period are provided in Table 6 and Table 7, respectively. These values are the peak 

on-site emissions during each analysis year, plus maximum annual off-site emissions. The 

modeling accounts for implementation of AQ-IAMF#1 through AQ-IAMF#5. Emissions for each 

Project alternative are presented and analyzed in this General Conformity Determination.

As shown in Table 6, NOX emissions would not exceed the General Conformity de minimis

threshold in the SFBAAB under Alternative A, and would exceed the threshold in 2022 and 2023

under Alternative B. Emissions of all other pollutants would be less than the applicable de minimis

thresholds. As shown in Table 7, emissions of all pollutants would be less than the applicable de 

minimis thresholds in the SJVAB.

Table 6 San Francisco to San Jose Annual Construction Emissions in the SFBAAB (tons 

per year)1

Alternative/Year VOC NOX CO SO2

2 PM10 PM2.5

Alternative A

2021 2 35 51 0 24 6

2022 4 97 121 1 59 15

2023 3 85 101 0 54 13

2024 3 71 92 0 49 11

2025 4 90 126 0 49 14

Alternative B

2021 2 39 57 0 27 7

2022 5 115 156 1 75 18

2023 4 103 122 1 65 16

2024 3 91 109 0 59 14

2025 4 96 132 0 55 15

General Conformity Threshold

SFBAAB Threshold 100 100 None 100 None 100

Sources: CAPCOA 2017; CARB 2018; USEPA 1998, 2006, 2011; Scholz 2018, 2020, 2021

CO = carbon monoxide

N/A = not applicable 

NOX = oxides of nitrogen 

PM2.5 = particulate matter smaller than or 

equal to 2.5 microns in diameter 

PM10 = particulate matter smaller than or 

equal to 10 microns in diameter 

SFBAAB = San Francisco Bay Area Air Basin 

SO2 = sulfur dioxide 

VOC = volatile organic compound

Values less than 0.5 have been rounded to zero. 

Exceedances of the General Conformity thresholds are shown in bold. 

1 Emissions results include implementation of air quality impact avoidance and minimization features, as described in Chapter 5.

2 Although the SFBAAB is in attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de minimis thresholds are used.
Chapter 9 Estimated Emission Rates and Comparison

to De Minimis Thresholds

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9-2 | Page San Francisco to San Jose Project Section Draft General Conformity Determination

Table 7 San Francisco to San Jose Annual Construction Emissions in the SJVAB (tons per 

year)1

Alternative/Year VOC NOX CO SO2

2 PM10 PM2.5

Alternative A

2021 0 0 0 0 0 0

2022 0 6 1 0 1 0

2023 0 3 0 0 0 0

2024 0 0 0 0 0 0

2025 0 0 0 0 0 0

2026 0 0 0 0 0 0

Alternative B

2021 0 0 0 0 0 0

2022 0 6 1 0 1 0

2023 0 6 1 0 1 0

2024 0 5 1 0 1 0

2025 0 0 0 0 0 0

2026 0 0 0 0 0 0

General Conformity Threshold

SJVAB Threshold 10 10 N/A 70 100 70

Sources: CAPCOA 2017; CARB 2018; USEPA 1998, 2006, 2011; Scholz 2018, 2020, 2021

CO = carbon monoxide 

N/A = not applicable 

NOX = oxides of nitrogen 

PM2.5 = particulate matter smaller than or 

equal to 2.5 microns in diameter 

PM10 = particulate matter smaller than or 

equal to 10 microns in diameter 

SJVAB = San Joaquin Valley Air Basin 

SO2 = sulfur dioxide 

VOC = volatile organic compound

Values less than 0.5 have been rounded to zero. 

Exceedances of the general conformity thresholds are shown in bold. 

1 Emissions results include implementation of air quality impact avoidance and minimization features, as described in Chapter 5.

2 Although the SJVAB is in attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de minimis thresholds are used.
Chapter 10 Regional Effects

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10 REGIONAL EFFECTS 

As shown in Section 3.3.6.2 of the Final EIR/EIS, the total regional emissions for all applicable 

pollutants are lower during the operations phase of the Project than under No Project conditions 

(and would therefore not exceed the de minimis emission thresholds). As such, only emissions 

generated during the construction phase were compared to the conformity threshold levels to 

determine conformity compliance. As shown in Tables 6 and 7, construction-phase emissions, 

compared to the General Conformity applicability rates, are as follows:

• Annual estimated NOX emissions in the SFBAAB are less than the applicability rate of 100 tpy

in all years under Alternative A, but greater than 100 tpy in 2022 and 2023 under Alternative

B with implementation of IAMFs.

• Annual estimated VOC, SO2, and PM2.5 emissions are less than the applicability rates in the

SFBAAB with implementation of IAMFs, for all years and alternatives.

• Because the SFBAAB is federally designated attainment for CO and PM10, the applicability

rates do not apply and no conformity evaluation is required for CO and PM10.

• Annual estimated emissions of all pollutants are less than the applicability rates in the SJVAB

with implementation of IAMFs, for all years and alternatives.

Therefore, a General Conformity Determination is required for the Project for NOX for the years 

during construction when the emissions would exceed the de minimis thresholds.
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Chapter 11 General Conformity Evaluation

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11 GENERAL CONFORMITY EVALUATION

For federal actions subject to a General Conformity evaluation, the regulations delineate several 

ways an agency can demonstrate conformity (40 C.F.R. § 93.158). This section summarizes the 

findings that were used to make the determination for the Project.

11.1 Conformity Requirements of Proposed Project

Based on the results shown in Table 6, a conformity determination is required for constructionphase emissions for NOX because annual estimated emissions are greater than the applicability 

rates of 100 tpy in the SFBAAB.

11.2 Compliance with Conformity Requirements

NOX (a precursor to O3) emissions caused by the construction of the Project will not result in an 

increase in regional NOX emissions in the SFBAAB, because exceedances will be mitigated by 

offsets. This will be achieved by additional on-site controls and offsetting the remaining NOX

emissions generated by the construction of the Project in a manner consistent with the General 

Conformity regulations. 

Any required offsets are anticipated to be accomplished by an agreement between the Authority, 

BAAQMD, and the Bay Area Clean Air Foundation. The requirements for offsets (as described 

below) will be implemented as part of the Project, and as described in the mitigation measures in

the Final EIR/EIS:

AQ-MM#1: Construction Emissions Reductions—Requirements for Use of Zero Emission 

and/or Near Zero Emission Vehicles and Off-Road Equipment

This mitigation measure will reduce the impact of construction emissions from project-related onroad vehicles and off-road equipment. 

The Authority and all project construction contractors will require that a minimum of 25 percent, 

with a goal of 100 percent, of all light-duty on-road vehicles (e.g., passenger cars, light-duty 

trucks) associated with the project (e.g., on-site vehicles, contractor vehicles) use zero emission 

(ZE) or near-zero emission (NZE) technology.

The Authority and all project construction contractors will have the goal that a minimum of 25 

percent of all heavy-duty on-road vehicles (e.g., for hauling, material delivery and soil 

import/export) associated with the project use ZE or NZE technology. 

The Authority and all project construction contractors will have the goal that a minimum of 10 

percent of off-road construction equipment use ZE or NZE vehicles. 

If local or state regulations mandate a faster transition to using ZE and/or NZE vehicles at the 

time of construction, the more stringent regulations will be applied. For example, EO N-79-20, 

issued by California Governor Newsom September 23, 2020, currently states the following:

• Light-duty and passenger car sales be 100 percent ZE vehicles by 2035

• Full transition to ZE short haul/drayage trucks by 2035

• Full transition to ZE heavy-duty long-haul trucks, where feasible, by 2045

• Full transition to ZE off-road equipment by 2035, where feasible.

The project will have a goal of surpassing the requirements of these or other future regulations as 

a mitigation measure. 

Because the commercial availability of future electric equipment and vehicles is unknown, 

emissions reductions achieved by AQ-MM#1 cannot currently be quantified or included in the 

analysis.
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AQ-MM#2: Offset Project Construction Emissions in the SFBAAB 

Prior to issuance of construction contracts, the Authority will be required to enter into an 

agreement with BAAQMD to reduce ROG/VOC and NOX emissions to the required levels. The 

required levels in the SFBAAB are as follows:

• For emissions in excess of the General Conformity de minimis thresholds (NOX): net zero.

• For emissions not in excess of General Conformity de minimis thresholds but above the 

BAAQMD’s daily emission thresholds (ROG/VOC and NOX): below the appropriate CEQA 

threshold levels.

The mitigation offset fee amount will be determined at the time of mitigation to fund one or more 

emissions reduction projects within the SFBAAB. The offset fee will be determined by the 

Authority and BAAQMD based on the type of projects that present appropriate emission reduction 

opportunities. These funds may be spent to reduce either VOC or NOX emissions (O3

precursors). Documentation of payment will be provided to the Authority or its designated 

representative.

The agreement will include details regarding the annual calculation of required offsets the 

Authority must achieve, funds to be paid, administrative fee, and the timing of the emissions 

reductions projects. Acceptance of this fee by BAAQMD will serve as an acknowledgment and 

commitment by BAAQMD to undertake the following steps: (1) implement an emissions reduction 

project(s) within a timeframe to be determined based on the type of project(s) selected after 

receipt of the mitigation fee designed to achieve the emissions reduction objectives; and 

(2) provide documentation to the Authority or its designated representative describing the 

project(s) funded by the mitigation fee, including the amount of emissions reduced (tons per year) 

in the SFBAAB from the emissions reduction project(s). To qualify under this mitigation measure, 

the specific emissions reduction project(s) must result in emissions reductions in the SFBAAB 

that are real, surplus, quantifiable, enforceable, and would not otherwise be achieved through 

compliance with existing regulatory requirements or any other legal requirement. Pursuant to 

40 C.F.R. Section 93.163(a), the necessary reductions must be achieved (contracted and 

delivered) by the applicable year in question. Funding will need to be received prior to contracting 

with participants and should allow enough time to receive and process applications to fund and 

implement off-site reduction projects prior to commencement of project activities being reduced. 

This would equate roughly to 1 year prior to the required mitigation; additional lead time may be 

necessary depending on the level of off-site emissions reductions required for a specific year.

This mitigation measure will be effective in offsetting emissions generated during construction of 

the project through the funding of emissions reduction projects. It is BAAQMD’s experience that 

implementation of an agreement is feasible mitigation that effectively achieves actual emissions 

reductions.

This mitigation measure would not be expected to adversely affect air quality in the SFBAAB 

because purchasing emissions offsets would not result in any physical change to the 

environment, and therefore would not result in other secondary environmental impacts. In 

addition to VOC and NOX, emissions reduction projects could reduce other criteria pollutants and 

GHGs. However, this would be a beneficial secondary impact of this mitigation measure and is 

not a required outcome to mitigate any impacts of the project.

11.3 Consistency with Requirements and Milestones in Applicable State 

Implementation Plan

The General Conformity regulations state that notwithstanding the other requirements of the rule, 

a federal action may not be determined to conform unless the total of direct and indirect 

emissions from the federal action is in compliance or consistent with all relevant requirements 

and milestones in the applicable SIP (40 C.F.R. § 93.158(c)). This includes, but is not limited to,

such issues as reasonable further progress schedules, assumptions specified in the attainment or 

maintenance demonstration, prohibitions, numerical emission limits, and work practice standards. 
Chapter 11 General Conformity Evaluation

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This section briefly addresses how the construction emissions for the Project were assessed for 

SIP consistency for this evaluation.

11.3.1 Applicable Requirements from U.S. Environmental Protection Agency

The USEPA promulgates requirements to support the goals of the CAA with respect to the 

NAAQS. Typically, these requirements take the form of rules regulating emissions from significant 

new sources, including emission standards for major stationary point sources and classes of 

mobile sources, as well as permitting requirements for new major stationary point sources. Since 

states have the primary responsibility for implementation and enforcement of requirements under 

the CAA and can impose stricter limitations than the USEPA, the USEPA requirements often 

serve as guidance to the states in formulating their air quality management strategies.

11.3.2 Applicable Requirements from California Air Resources Board

In California, to support the attainment and maintenance of the NAAQS, the CARB is primarily 

responsible for regulating emissions from mobile sources. The USEPA has delegated authority to 

the CARB to establish emission standards for on-road and some non-road vehicles separate from 

the USEPA vehicle emission standards, although the CARB is preempted by the CAA from 

regulating emissions from many non-road mobile sources, including marine craft. Emission 

standards for preempted equipment can only be set by the USEPA.

11.3.3 Applicable Requirements from Bay Area Air Quality Management District 

To support the attainment and maintenance of the NAAQS in the SFBAAB, the BAAQMD has

primarily been responsible for regulating emissions from stationary sources. The BAAQMD 

develops and updates its air quality management plans regularly to support the California SIP. 

While the plans contain rules and regulations geared to attain and maintain the NAAQS, these 

rules and regulations also have the much more difficult goal of attaining and maintaining the 

CAAQS.

11.3.4 Consistency with Applicable Requirements for the California High-Speed 

Rail Authority 

The Authority already complies with, and would continue to comply with, the rules and regulations 

implemented and enforced by federal and state agencies14 to protect and enhance ambient air 

quality in the SFBAAB. In particular, because of the long persistence of challenges to attain the 

ambient air quality standards in the SFBAAB, the rules and regulations promulgated by the CARB

and the BAAQMD are among the most stringent in the U.S. The Authority would continue to 

comply with all existing applicable air quality regulatory requirements for activities over which it 

has direct control and would meet in a timely manner all regulatory requirements that become 

applicable in the future.

The following are appropriate USEPA, CARB, and BAAQMD rules that are standard practices

and best management practices for construction in the SFBAAB, including control of emissions

and exhaust:

• BAAQMD Regulation 2, Rule 2 (New Source Review)—This rule contains requirements for

Best Available Control Technology and emission offsets.

• BAAQMD Regulation 2, Rule 5 (New Source Review of Toxic Air Contaminants)—This

rule outlines guidance for evaluating toxic air contaminant emissions and their potential

health risks.

• BAAQMD Regulation 6, Rule 1 (Particulate Matter)—This rule restricts emissions of PM

darker than No. 1 on the Ringlemann Chart to less than 3 minutes in any 1 hour.

14 The Authority is a state agency and therefore is not required to comply with regional and local regulations; however, it

has endeavored to design and build the HSR system to be compatible with regional and local regulations.
Chapter 11 General Conformity Evaluation

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• BAAQMD Regulation 6, Rule 6 (Prohibition of Trackout)—This rule limits the quantity of 

PM in the atmosphere through control of trackout of solid materials onto paved public roads 

outside the boundaries of Large Bulk Material Sites, Large Construction Sites, and Large 

Disturbed Surface sites including landfills.

• BAAQMD Regulation 7 (Odorous Substances)—This regulation establishes general odor 

limitations on odorous substances and specific emission limitations on certain odorous 

compounds.

• BAAQMD Regulation 8, Rule 3 (Architectural Coatings)—This rule limits the quantity of 

ROG in architectural coatings.

• BAAQMD Regulation 9, Rule 6 (Nitrogen Oxides Emission from Natural Gas–Fired 

Boilers and Water Heaters)—This rule limits emissions of NOX generated by natural gas–

fired boilers.

• BAAQMD Regulation 9, Rule 8 (Stationary Internal Combustion Engines)—This rule 

limits emissions of NOX and CO from stationary internal combustion engines of more than 50 

horsepower.

• BAAQMD Regulation 11, Rule 2 (Asbestos Demolition, Renovation, and 

Manufacturing)—This rule controls emissions of asbestos to the atmosphere during 

demolition, renovation, milling, and manufacturing and establishes appropriate waste 

disposal procedures.

• BAAQMD CEQA Guidelines—The BAAQMD prepared its CEQA Air Quality Guidelines to 

assist lead agencies and project applicants in evaluating the potential air quality impacts of 

projects in the SFBAAB (BAAQMD 2017b). The Air Quality Guidelines provide BAAQMDrecommended procedures for evaluating potential air quality impacts during the CEQA 

environmental review process. The documents provide guidance on evaluating short-term 

(construction) and long-term (operational) air emissions. The CEQA Air Quality Guidelines

used in this evaluation contain guidance on the following:

– Criteria and thresholds for determining whether a project may have a significant adverse 

air quality impact

– Specific procedures and modeling protocols for quantifying and analyzing air quality 

impacts

– Methods to mitigate air quality impacts

– Information for use in air quality assessments and environmental documents that will be 

updated more frequently, such as air quality data, regulatory setting, climate, and 

topography

• USEPA Rule 40 C.F.R. Part 89, Control of Emissions from New and In-Use Nonroad 

Compression-Ignition Engines: This rule requires stringent emission standards for mobile 

nonroad diesel engines of almost all types using a tiered phase-in of standards

• CARB Rule 13 California Code of Regulations Section 1956.8, California Exhaust 

Emission Standards and Test Procedures for 1985 and Subsequent Model Heavy-Duty 

Diesel Engines and Vehicles: This rule requires significant reductions in emissions of NOX, 

PM, and nonmethane organic compounds using exhaust treatment on heavy-duty diesel 

engines manufactured in model year 2007 and later years.
Chapter 12 Estimated Emission Rates and Comparison 

to De Minimis Thresholds—Cumulative Analysis

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12 ESTIMATED EMISSION RATES AND COMPARISON 

TO DE MINIMIS THRESHOLDS—CUMULATIVE ANALYSIS

The RSA for cumulative air quality impacts is the SFBAAB and SJVAB.

15 While they are separate 

projects for purposes of planning the HSR system, construction of the San Francisco to San Jose 

Project Section would overlap with the construction period for the following other HSR sections: 

• San Jose to Merced, construction in the SFBAAB and SJVAB between 2022 and 2028

• Central Valley Wye, construction in the SJVAB in 2022 and material hauling in the SFBAAB

in 2022

• Merced to Fresno, construction in the SJVAB in 2022 (no emissions in the SFBAAB)

• Fresno to Bakersfield, construction in the SJVAB between 2022 and 2023 (no emissions in

the SFBAAB)

• Bakersfield to Palmdale, construction in the SJVAB between 2022 and 2025 (no emissions in

the SFBAAB)

Overlapping construction activities could add to cumulative air quality impacts within the SFBAAB

and SJVAB. For purposes of full disclosure of the potential impacts, the cumulative emissions 

that could result from potential concurrent construction activities are presented in Table 8 for the 

SFBAAB and Table 9 for the SJVAB. As the analysis demonstrates, concurrent construction 

could result in exceedances of the NOX General Conformity de minimis threshold in the SFBAAB

and the VOC and NOX General Conformity de minimis thresholds in the SJVAB. The Authority 

has entered into an agreement with the SJVAPCD that will offset all emissions of VOC, NOx, and 

PM generated in the SJVAB by construction of the HSR Project to net zero. Pursuant to AQMM#-2, the Authority would enter into an agreement with BAAQMD to offset VOC and NOX

emissions from construction of the San Francisco to San Jose Project Section to net zero, for 

each year in which VOC or NOX emissions from construction exceed the federal general 

conformity de minimis thresholds. These commitments currently cover VOC and NOX emissions, 

although reduction projects implemented to reduce O3 precursors may also contribute to PM 

reductions.

The Merced to Sacramento Project Section would also generate emissions in the SJVAB. 

However, this section would not be completed until Phase 2, which would occur after completion 

of the mandated Los Angeles to San Francisco line. It is likely that construction activities would 

therefore take place after the San Francisco to San Jose Project Section is completed (i.e., after 

2025).

15 Although the San Francisco to San Jose Project Section is not in the SJVAB, the SJVAB nonetheless is part of the

cumulative analysis because the HSR project sections in the SJVAB could add to cumulative air quality impacts in the 

SFBAAB. In addition, some truck travel associated with construction of the LMF would occur in the SJVAB. The NCCAB is 

not included in the cumulative air quality analysis because no HSR project sections are located in the NCCAB.
Chapter 12 Estimated Emission Rates and Comparison 

to De Minimis Thresholds—Cumulative Analysis

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Table 8 Overlapping HSR System Construction Emissions in the San Francisco Bay Area 

Air Basin (tons per year)

Year and Project Section VOC NOX CO SO2

1 PM10 PM2.5

2022

JM2,3 6 77 192 1 47 11

FJ2,4,5 5 115 156 1 75 18

CVY 1 31 9 <1 1 1

Total 11 223 357 1 123 30

2023

JM2,3 7 118 255 1 70 17

FJ2,4,5 4 103 122 0 65 16

CVY 0 0 0 0 0 0

Total 10 221 387 1 135 33

2024

JM2,3 9 156 304 1 95 23

FJ2,4,5 3 91 109 0 59 14

CVY 0 0 0 0 0 0

Total 12 248 413 1 154 37

2025

JM2,3 7 139 241 1 79 19

FJ2,4,5 4 96 132 0 55 15

CVY 0 0 0 0 0 0

Total 12 235 372 1 134 35

General Conformity Threshold

SFBAAB threshold 100 100 N/A 100 N/A 100

Sources: See Table 6 in Section 10; Authority and FRA 2017

The Merced to Fresno, Fresno to Bakersfield, and Bakersfield to Palmdale Project Sections are omitted because they would not produce 

construction emissions in the SFBAAB.

Emissions in 2021 are not shown because construction emissions for project sections other than FJ are not projected to occur in 2021.

Emissions in 2026 are not shown because construction emissions for the FJ Project Section in 2026 would be less than 0.5 tons of any pollutant.

CO = carbon monoxide 

CVY = Central Valley Wye 

FJ = San Francisco to San Jose 

IAMF = impact avoidance and minimization feature 

JM = San Jose to Merced 

N/A = not applicable 

NOX = oxides of nitrogen 

PM2.5 = particulate matter smaller than or equal to 2.5 microns in 

diameter 

PM10 = particulate matter smaller than or equal to 10 microns in diameter

RSA = resource study area 

SO2 = sulfur dioxide 

VOC = volatile organic compound

Sum of individual values may not equal total due to rounding.

Values less than 0.5 have been rounded to zero.

Exceedances of the applicable de minimis thresholds are shown in bold.

1 Although the SFBAAB is in attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de minimis thresholds are used.

2 Emissions results include implementation of air quality IAMFs, as described in Section 6.

3 Presents emissions under Alternative 4, which is the JM alternative with the greatest emissions in the SFBAAB.

4 Presents emissions under Alternative B, which is the FJ alternative with the greatest emissions in the SFBAAB.

5 To avoid double-counting, FJ values do not include the San Jose Diridon Station Approach Subsection.
Chapter 12 Estimated Emission Rates and Comparison 

to De Minimis Thresholds—Cumulative Analysis

California High-Speed Rail Authority April 2022

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Table 9 Overlapping HSR System Construction Emissions in the San Joaquin Valley Air 

Basin (tons per year)

Year1 VOC NOx CO SO2

2 PM10 PM2.5

2022

JM3,4 6 42 218 1 18 5

FJ3,4 0 6 1 0 1 0

B-P4 11 103 87 1 10 5

F-B4 <1 1 1 <1 <1 <1

M-F

4 5 4 3 <1 9 2

CVY4 2 44 20 <1 2 2

Total 25 200 331 2 40 13

2023

JM3,4 6 55 226 1 24 6

FJ3,4 0 6 1 0 1 0

B-P4 8 70 66 1 9 4

F-B4 <1 <1 <1 <1 <1 <1

M-F

4 0 0 0 0 0 0

CVY4 0 0 0 0 0 0

Total 14 132 293 2 34 10

2024

JM3,4 6 56 220 1 23 5

FJ3,4 0 5 1 0 1 0

B-P4 6 50 50 1 6 3

F-B4 0 0 0 0 0 0

M-F

4 0 0 0 0 0 0

CVY4 0 0 0 0 0 0

Total 12 111 271 2 30 8

2025

JM3,4 6 54 209 1 21 5

FJ3,4 0 0 0 0 0 0

B-P4 2 10 11 1 1 1

F-B4 0 0 0 0 0 0

M-F

4 0 0 0 0 0 0

CVY4 0 0 0 0 0 0

Total 8 64 220 2 22 6
Chapter 12 Estimated Emission Rates and Comparison 

to De Minimis Thresholds—Cumulative Analysis

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Year1 VOC NOx CO SO2

2 PM10 PM2.5

General Conformity Threshold

SJVAB threshold 10 10 - 70 100 70

Source: Authority 2021

Sum of individual values may not equal total due to rounding.

Values less than 0.5 have been rounded to zero.

Exceedances of the de minimis thresholds are shown in bold.

B-P = Bakersfield to Palmdale 

CO = carbon monoxide 

CVY = Central Valley Wye 

F-B = Fresno to Bakersfield 

FJ = San Francisco to San Jose 

IAMF = impact avoidance and minimization feature 

JM = San Jose to Merced 

M-F = Merced to Fresno 

NOX = oxides of nitrogen 

PM2.5 = particulate matter 2.5 microns in diameter or less 

PM10 = particulate matter 10 microns in diameter or less 

RSA = resource study area 

SO2 = sulfur dioxide 

VOC = volatile organic compound 

1 The analysis assumed that Project construction would take place from 2022 to 2025, and that construction of other HSR project sections would 

occur according to the schedules presented in their respective environmental documents.

2 Although the SJVAB is in attainment for SO2, because SO2 is a precursor for PM2.5, the PM2.5 General Conformity de minimis thresholds are used.

3 Emissions results include implementation of air quality IAMFs, as described in Section 6.

4 The highest annual emissions for each pollutant among the analyzed alternatives is presented. 
Chapter 13 Reporting and Public Comments

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13 REPORTING AND PUBLIC COMMENTS

To support a decision concerning the Project, the FRA is issuing this draft General Conformity 

Determination for a 30-day public and agency review. In developing the analysis underlying this 

general conformity determination, the Authority has consulted extensively with the BAAQMD on a 

variety of technical and modeling issues. The Authority has also consulted with the USEPA and 

CARB on the overall approach to demonstrating general conformity. 

The FRA will issue a notice in the Federal Register announcing the availability of the draft general 

conformity determination and requesting written public comments during a 30-day period. This 

draft conformity determination will be made available on FRA’s docket at 

https://www.regulations.gov/, Docket FRA-2022-0026.

Any comments on the draft General Conformity Determination will be addressed in the Final 

General Conformity Determination.

14 FINDINGS AND CONCLUSIONS 

FRA conducted a General Conformity evaluation consistent with 40 C.F.R. Part 93 Subpart B. 

The General Conformity regulations apply at this time to this Project because the Project is in an 

area that is designated as a marginal nonattainment area for the O3 NAAQS and a moderate 

nonattainment area for the PM2.5 NAAQS. The FRA conducted the General Conformity evaluation 

consistent with all regulatory criteria and procedures and following the Authority’s coordination 

with the USEPA, BAAQMD, and CARB. As a result of this review, the FRA concluded, because

Project-generated emissions would either be fully offset (for construction phase) or less than zero 

(for operational phase), that the Project’s emissions can be accommodated in the SIP for the 

SFBAAB. The FRA has determined that the Project as designed would conform to the approved 

SIP based on the following: 

• The Authority commits that construction-phase NOX emissions will be offset consistent with

the applicable federal regulations through an agreement with the BAAQMD.

• The Authority and the BAAQMD will enter into a contractual agreement to offset the Project’s

NOX emissions by providing funds for the BAAQMD to fund grants for projects that achieve

the necessary emission reductions.

• The BAAQMD will seek and implement the necessary emission reduction measures, using

Authority funds.

• The BAAQMD will serve as administrator of the emissions reduction projects and verifiers of

the successful mitigation effort.

Therefore, the FRA intends to issue a final determination that concludes that the Project, as 

designed, conforms to the purpose of the approved SIP and is consistent with all applicable 

requirements.
Chapter 14 Findings and Conclusions

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Chapter 15 References

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15 REFERENCES 

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———. 2016. Bay Area Air Quality Management District Permit Handbook. 

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———. 2019a. San Francisco to San Jose Project Section Record Preliminary Engineering for 

Project Definition. April 2019.

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Definition. May 2019.

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communications to David Ernst (ICF) regarding construction data for LMF.

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U.S. Environmental Protection Agency (USEPA). 1994. General Conformity Guidance: Questions 

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———. 2011. “Section 13.2.1: Paved Roads.” In Compilation of Air Pollutant Emission Factors. 

www.epa.gov/ttn/chief/ap42/ch13/bgdocs/b13s0201.pdf (accessed October 2016).

———. 2018a. AirData Monitor Values Report. www3.epa.gov/airdata/ad_rep_mon.html

(accessed September 2018).

———. 2018b. The Green Book Nonattainment Areas for Criteria Pollutants. June 30, 2018. 

www.epa.gov/green-book (accessed August 2018).
Attachment A 

California High-Speed Rail Authority Project Environmental Document April 2022

San Francisco to San Jose Project Section Final Federal General Conformity Determination 

ATTACHMENT A: LETTERS OF AGREEMENT WITH BAAQMD
ALAMEDA COUNTY

John J. Bauters

(Vice Chair)

Pauline Russo Cutter

David Haubert

Nate Miley

CONTRA COSTA COUNTY

John Gioia

David Hudson

Karen Mitchoff

(Chair)

Mark Ross

MARIN COUNTY

Katie Rice

NAPA COUNTY

Brad Wagenknecht

SAN FRANCISCO COUNTY

Tyrone Jue

(SF Mayor’s Appointee)

Myrna Melgar

Shamann Walton

SAN MATEO COUNTY

David J. Canepa

Carole Groom 

Davina Hurt

(Secretary)

SANTA CLARA COUNTY

Margaret Abe-Koga

Cindy Chavez

Rich Constantine

Rob Rennie

SOLANO COUNTY

Erin Hannigan

Lori Wilson

SONOMA COUNTY

Teresa Barrett

Lynda Hopkins

Jack P. Broadbent

EXECUTIVE OFFICER/APCO

375 BEALE STREET, SUITE 600 • SAN FRANCISCO CA • 94105 • 415.771.6000 • www.Air District.gov

March 11, 2022

Brian Kelly

Chief Executive Officer

California High Speed Rail Authority

770 L Street, Suite 620, 

Sacramento, CA 95814

Re: Intent to offset future emissions during construction of San Francisco to 

San Jose and San Jose to Merced Sections of the California High-Speed 

Rail System for purposes of Federal Clean Air Act General Conformity

Dear Mr. Kelly,

Purpose

The purpose of this letter is to document that the Bay Area Air Quality 

Management District (Air District) and the Bay Area Clean Air Foundation

(Foundation) intend to work with the California High Speed Rail Authority 

(Authority) on off-site emission reduction measures to support General

Conformity for the San Francisco to San Jose and San Jose to Merced 

Project Sections of the California High-Speed Rail (HSR) System.

Projects

The California HSR System will provide intercity, high-speed service on more 

than 800 miles of guideway throughout California, connecting the major 

population centers of Sacramento, the San Francisco Bay Area, the southern 

Central Valley, Los Angeles, the Inland Empire, Orange County, and San 

Diego. The San Francisco to San Jose (FJ) and San Jose to Merced Project 

(JM) Sections (“Projects” or “Actions”) are critical links connecting the Bay 

Area to the Central Valley project sections.

General Conformity Rule

The General Conformity Rule, as codified in Title 40 Code of Federal 

Regulations Part 93, Subpart B, establishes the process by which federal 

agencies determine conformance of proposed projects that are federally 

funded or require federal approval with applicable air quality standards. This 

determination must demonstrate that a proposed action would not cause or 

contribute to new violations of air quality standards, exacerbate existing 

violations, or interfere with timely attainment or required interim emissions

reductions towards attainment. The Authority, as the proponent of the 

Actions, is receiving federal grant funds through the Federal Railroad 

Administration’s (FRA) High-Speed Intercity Passenger Rail program. The 

Actions may also receive FRA safety approvals. Because of the federal 
Brian Kelly March 11, 2022

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funding and potential safety approvals, the Actions are subject to the General Conformity 

Rule; and because construction-phase emissions (without mitigation) would exceed 

General Conformity de minimis thresholds, the Actions are not exempt and must 

demonstrate how the projects intend to achieve conformity.

General Conformity Determinations

It is the Air District’s understanding that the draft General Conformity Determinations for 

the Actions document FRA’s findings that the Actions comply with the General Conformity 

Rule, conform to the purposes of the State Implementation Plan, and are consistent with 

all applicable requirements. FRA will issue the draft General Conformity Determination for 

the San Francisco to San Jose Project Section for public review and comment and has 

issued the draft General Conformity Determination for the San Jose to Merced Project 

Section for public review. Neither Air District nor the Bay Area Clean Air Foundation have 

reviewed or commented on the draft Conformity Determinations. 

The draft General Conformity Determinations are based on the Impact Avoidance and 

Minimization Measures (IAMF) and Mitigation Measures (MM) that are described in 

Appendix 2-E and Section 3.3.7 of the Final EIR/EISs for both Actions and that will be 

implemented for the Actions. This compliance is demonstrated as follows:

• The operation of the Action would result in a reduction of regional emissions of all 

applicable air pollutants and would not cause a localized exceedance of an air quality 

standard; and 

• Whereas emissions generated during the construction of the Actions would exceed 

General Conformity de minimis thresholds for one pollutant, these emission 

increases would be offset through off-site emissions reductions projects funded by 

the Authority and administered by Air District’s support organization, the Bay Area 

Clean Air Foundation, a public charity. 

Based on the Authority’s current emissions analysis, construction emissions exceed 

General Conformity de minimis thresholds for nitrogen oxides (NOx) in the San Francisco 

Bay Area Air Basin. The Authority has advised that these exceedances are based on 

current construction schedule and equipment estimates and based on the available 

information to date. The methodology used by the Authority in creating these estimates is 

similar to what was used for estimating the emissions for the EIR/EISs for the Authority’s

Merced to Fresno and Fresno to Bakersfield Project Sections. After seven years of 

construction in the Central Valley, the Authority reports that the estimates in those EIR/EISs 

are conservative and actual emissions from construction are currently lower than EIR/EIS 

estimates by 50 to 70 percent. 

Impact Avoidance and Minimization Features

The Authority has incorporated the following IAMFs into the Projects: 
Brian Kelly March 11, 2022

Page 3

• AQ-IAMF#1: Fugitive Dust Emissions: The contractor will employ several control 

measures to minimize and control fugitive dust emissions and prepare a fugitive 

dust control plan for each distinct construction segment.

• AQ-IAMF#2: Selection of Coatings: The contractor will use lower VOC content 

paint than that required by Air District Regulation 8, Rule 3, when available.

• AQ-IAMF#3: Renewable Diesel: The contractor will use renewable diesel fuel to 

minimize and control exhaust emissions from all heavy-duty diesel-fueled 

construction diesel equipment and on-road diesel trucks.

• AQ-IAMF#4: Reduce Criteria Exhaust Emissions from Construction 

Equipment: All heavy-duty off-road construction diesel equipment used during the 

construction phase will meet Tier 4 engine requirements.

• AQ-IAMF#5: Reduce Criteria Exhaust Emissions from On-Road Construction 

Equipment: All diesel on-road trucks used to haul construction materials will be 

model year 2010 or newer.1

• AQ-IAMF#6: Reduce the Potential Impact of Concrete Batch Plants: The 

contractor will prepare a technical memorandum documenting the concrete batch 

plant siting criteria, including locating the plant at least 1,000 feet from sensitive 

receptors, and utilization of typical control measures. 

Mitigation Measures

The Authority has committed to the following mitigation measure in its Northern California 

environmental documentation and has committed in its environmental documentation to 

incorporating this measure into its future Northern California construction contracts. 

AQ-MM#2 2- Construction Emissions Reductions—Requirements for Use of 

Zero Emission and/or Near Zero Emission Vehicles and Off-Road Equipment

This mitigation measure will reduce the impact of construction emissions from 

project-related on-road vehicles and off-road equipment.

The Authority and all project construction contractors will require that a minimum of 

25 percent, with a goal of 100 percent, of all light-duty on-road vehicles (e.g., 

passenger cars, light-duty trucks) associated with the project (e.g., on-site vehicles, 

contractor vehicles) use zero emission (ZE) or near-zero emission (NZE) 

technology.

1

IAMFs listed are from the San Jose to Merced Project Section. AQ-IAMF#5 in San Francisco to San Jose Project Section is slightly 

different and reads as follows: All on road trucks will consist of an average fleet mix of equipment year 2010 or newer, but no less than 

the average fleet mix for the current calendar year as set forth in the CARB’s EMFAC 2014 database.

2 This mitigation measure number is specific to the San Jose to Merced Project Section Final EIR/EIS. This same measure is AQMM#1 in the San Francisco to San Jose Project Section Final EIR/EIS.

The Authority and all project construction contractors will have the goal that a 

minimum of 25 percent of all heavy-duty on-road vehicles (e.g., for hauling, material 

delivery and soil import/export) associated with the construction activities for the San 
Brian Kelly March 11, 2022

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Francisco to San Jose and San Jose to Merced Sections of the HSR System use 

ZE or NZE technology. 

The Authority and all project construction contractors will have the goal that a 

minimum of 10 percent of off-road construction equipment use ZE or NZE vehicles.

If local or state regulations mandate a faster transition to using ZE and/or NZE 

vehicles at the time of construction, the more stringent regulations will be applied. 

For example, Executive Order (EO) N-79-20, issued by California Governor 

Newsom September 23, 2020, currently states the following:

• Light duty and passenger car sales be 100 percent ZE vehicles by 2035

• Full transition to ZE short haul/drayage trucks by 2035

• Full transition to ZE heavy-duty long-haul trucks, where feasible, by 2045

• Full transition to ZE off-road equipment by 2035, where feasible. 

The project will have a goal of surpassing the requirements of these or other future 

regulations as a mitigation measure. 

It is the Air District’s understanding that the Authority already mandates that all such 

equipment meet the highest emission standard codified by the U.S. Environmental 

Protection Agency (EPA) —Tier 4 and that the Authority intends for its implementation 

strategy to go further, mandating through contractual measures that by 2030, 10 percent of 

off-road equipment be ZEV at start of construction, and sets the goal of 100 percent ZEV 

for such equipment by 2035.

Future Emissions Estimates

It is the Air District’s understanding that since funding has not been fully secured for the 

Projects, construction emissions would be recalculated after funding is secured, prior to the 

implementation of any off-site emissions reduction programs and prior to construction 

activities commencing. As such, the Authority reports that the following steps will be 

followed to demonstrate conformity:

• Once construction funding is secured for the project section, a revised construction 

schedule will be developed.

• Based on the new schedule, a construction plan will be developed and analyzed to 

determine the emissions generated by construction. 

• At the time of analysis, the IAMFs and MMs will be revisited and may be updated to 

include technologies and methodologies that were not considered in the earlier analysis.

This review and implementation of updated measures will aid the projects in reducing 

the generation of emissions due to construction. The Air District strongly recommends 

that these additional measures include the following:
Brian Kelly March 11, 2022

Page 5

o All on-road heavy-duty trucks traveling to the construction site shall have 

engines that are no more than seven years old (i.e., in 2022, engines must 

be 2015 model year or newer). 

o All off-road equipment shall use the highest tier engines available when zeroemissions equipment is not available (e.g. Tier 4 construction, rail, marine 

equipment). In place of Tier 4 engines, off-road equipment can incorporate 

retrofits such that emission reductions achieved equal or exceed that of a Tier 

4 engine. 

o All off-road equipment with a power rating below 19 kilowatts (e.g., plate 

compactors, pressure washers) shall be battery powered. 

o Diesel generators, including any designated for back-up, shall not be used at 

the project sites during construction unless absolutely necessary. If 

necessary, generators shall have Best Available Control Technology (BACT) 

that meets CARB's Tier 4 emission standards or meets the most stringent inuse standard, whichever has the least emissions. 

• Once emission estimates are calculated using the IAMF and MMs, the Authority will 

confirm whether the estimates are still above the applicable General Conformity de 

minimis thresholds.

• All affected air districts will be notified of the emission levels and consulted to offset 

emissions for those years/pollutants that exceed General Conformity de minimis

thresholds. Alternatively, the air districts could include these emissions in the applicable 

State Implementation Plan.

• The emission accounting program the Authority uses to track emissions for the 

segments currently being constructed will be utilized to actively quantify the construction 

emissions generated by the project. 

Conclusion

The Air District and the Bay Area Clean Air Foundation acknowledge the following:

• The Authority will ensure that the lowest level of construction emissions are 

generated through the use of IAMFs outlined in this document and rolling review of 

best available technologies. 

• The Authority will exhaust all on-site opportunities to reduce emissions during the 

construction phase, including from vehicles traveling to and from the project site, 

before seeking off-site NOx mitigation.

As such, by signing below the Air District and the Bay Area Clean Air Foundation commit 

to the following:

• The Air District will work with the Authority to mitigate all NOx emissions exceeding 

General Conformity de minimis thresholds to zero as required by General 

Conformity, through an off-site emissions reductions program. Funds from the 

Authority for mitigation offsets will be administered by Air District’s Bay Area Clean 

Air Foundation for the award of grants to Bay Area businesses, public agencies, and 
Brian Kelly March 11, 2022

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residents who will implement projects that reduce emissions of NOx, reactive organic 

gases, and particulate matter. The Bay Area Clean Air Foundation intends to enter 

into a contractual agreement with the Authority to implement this program, with the 

Authority providing funds for off-site emissions reductions projects that achieve the 

necessary emissions reductions. Current off-site emissions reductions programs 

work to cost-effectively reduce emissions from primarily mobile source projects. 

Project types may include, but are not limited to: 

o Grants to replace dirty diesel off-road equipment, e.g., tractors and 

agricultural equipment, marine, lawn and garden;

o Grants to replace older, high-polluting trucks and buses; and

o Grants to owners to scrap older, high-polluting vehicles.

• The Bay Area Clean Air Foundation requires adequate lead time to achieve 

emissions reductions, and understands that the Authority will commit to working with 

the Foundation well in advance of construction years during which emissions 

reductions may be necessary (no less than three years, for construction years 

estimated to require emissions reductions of 100 tons/year or more).

• The Bay Area Clean Air Foundation will seek and implement the necessary emission 

reduction measures to the extent possible, using Authority funds; and 

• The Bay Area Clean Air Foundation will serve in the role of administrator of the 

emissions reduction projects and verifier of the successful mitigation effort. 

Thank you for your continuing partnership with Air District and the Foundation to protect 

air quality, the climate and public health in the Bay Area.

Sincerely,

Jack P. Broadbent

Executive Officer/APCO Bay Area Air Quality Management District

President, Bay Area Clean Air Foundation

cc: Director Margaret Abe-Koga

Director David J. Canepa

Chair Cindy Chavez

Director Rich Constantine

Director Carole Groom 

Director Davina Hurt

Director Tyrone Jue

Director Rob Rennie

Director Shamann Walton