Noise and Vibration 

Technical Memorandum

Coachella Valley-San Gorgonio Pass Rail 

Corridor Service Program

May 2021
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Noise and Vibration Technical Memorandum

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Contents

1 Introduction.....................................................................................................................................1-1

1.1 Study Approach......................................................................................................................1-1

2 Program Location and Description ..............................................................................................2-1

2.1 Program Location...................................................................................................................2-1

2.2 Program Description...............................................................................................................2-1

2.2.1 Build Alternative Option 1 (Coachella Terminus)......................................................2-1

2.2.2 Build Alternative Option 2 (Indio Terminus) ..............................................................2-2

2.2.3 Build Alternative Option 3 (Indio Terminus with Limited Third Track).......................2-2

2.3 Construction ...........................................................................................................................2-3

2.3.1 Western Section........................................................................................................2-3

2.3.2 Eastern Section.........................................................................................................2-3

2.4 Operation................................................................................................................................2-4

3 Regulatory Framework ..................................................................................................................3-1

3.1 Federal ...................................................................................................................................3-1

3.1.1 Environmental Protection Agency.............................................................................3-1

3.1.2 Federal Railroad Administration/Federal Transit Administration Noise Impact 

Criteria.......................................................................................................................3-2

3.1.3 Federal Transit Administration Vibration Impact Criteria ..........................................3-6

3.1.4 Noise Control Act of 1972 .........................................................................................3-8

3.2 State .......................................................................................................................................3-8

3.2.1 California Noise Control Act ......................................................................................3-8

3.3 Local/Regional........................................................................................................................3-9

4 Methodology ...................................................................................................................................4-1

4.1 Noise ......................................................................................................................................4-1

4.1.1 Construction Noise....................................................................................................4-1

4.1.2 Operational Noise......................................................................................................4-2

4.2 Vibration .................................................................................................................................4-4

4.2.1 Construction Vibration...............................................................................................4-4

4.2.2 Operational Vibration.................................................................................................4-5

4.3 Tier 1/Program EIS/EIR Study Area.......................................................................................4-6
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5 Existing Conditions........................................................................................................................5-1

5.1 Physical Setting......................................................................................................................5-1

5.1.1 Noise- and Vibration-Sensitive Land Uses................................................................5-1

5.1.2 Existing Noise and Vibration Sources.......................................................................5-2

5.2 Existing Noise Levels .............................................................................................................5-6

5.3 Existing Vibration Levels ........................................................................................................5-9

6 Environmental Consequences......................................................................................................6-1

6.1 Overview ................................................................................................................................6-1

6.2 No Build Alternative................................................................................................................6-2

6.3 Build Alternative Options 1, 2, and 3......................................................................................6-2

6.3.1 Western Section........................................................................................................6-2

6.3.2 Eastern Section.......................................................................................................6-16

7 Tier 2 Environmental Review Considerations.............................................................................7-1

8 References ......................................................................................................................................8-1
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Tables

Table 3-1. Federal Transit Administration Construction Noise Impact Guidelines ....................................3-3

Table 3-2. Ground-borne Vibration Impact Criteria for General Assessment............................................3-7

Table 4-1. Construction Equipment Noise Emission Levels......................................................................4-2

Table 4-2. Typical Construction Equipment Vibration Levels ....................................................................4-4

Table 5-1. Existing Year (2018) Daily Train Operations within Program Corridor (One-Way Trips) .........5-3

Table 5-2. Ambient Noise Levels within Program Corridor from Existing Train Operations......................5-7

Table 6-1. Coachella Valley – San Gorgonio Pass Corridor Service Intercity Passenger Train 

Consist ..........................................................................................................................................6-3

Table 6-2. Proposed Coachella Valley – San Gorgonio Pass Rail Corridor Service Conceptual 

Train Schedule (Build Alternative Options 1, 2, and 3).................................................................6-4

Table 6-3. Summary of Train Volumes under Existing (2018) and with-Program Conditions (Build 

Alternative Options 1, 2, and 3) ....................................................................................................6-5

Table 6-4. Western Section Noise Levels from Existing-plus-Program Train Operations, Category 

2 (Residential) Land Uses.............................................................................................................6-7

Table 6-5. Western Section Noise Levels from Existing-plus-Program Train Operations, Category 

3 (Institutional) Land Uses within the Tier 1/Program EIS/EIR Study Area................................6-11

Table 6-6. Construction Equipment Noise Emission Levels by Distance................................................6-16

Table 6-7. Construction Equipment Vibration Levels by Distance...........................................................6-18

Table 6-8. Eastern Section Noise Levels from Existing-plus-Program Train Operations, Category 

2 (Residential) Land Uses (Colton-Coachella Section) within the Program Corridor.................6-21

Table 6-9. Eastern Section Noise Levels from Existing-plus-Program Train Operations, Category 

3 (Institutional) Land Uses (Colton-Coachella Section) within the Program Corridor.................6-22

Figures

Figure 2-1. Western Section of the Program Corridor (Build Alternative Options 1, 2, and 3)..................2-5

Figure 2-2. Eastern Section of the Program Corridor (Build Alternative Option 1)....................................2-7

Figure 2-3. Eastern Section of the Program Corridor (Build Alternative Options 2 and 3)........................2-9

Figure 3-1. Federal Transit Administration Noise Impact Criteria..............................................................3-5

Figure 3-2. Increase in Cumulative Noise Levels Allowed by Criteria .......................................................3-6

Figure 6-1. Program Noise Exposure Relative to Existing Conditions ....................................................6-15
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Appendices

Appendix A. Fundamental Concepts of Environmental Noise
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Abbreviations/Acronyms

Caltrans California Department of Transportation

CEQA California Environmental Quality Act

dB decibels

dBA A-weighted decibels

EIR environmental impact report 

EIS environmental impact statement

EPA Environmental Protection Agency

FRA Federal Railroad Administration

FTA Federal Transit Administration

FTA Manual FTA Transit Noise and Vibration Impact Assessment

LAUS Los Angeles Union Station

Ldn day-night average sound level

Leq equivalent sound level

Leq(h) 1-hour A weighted equivalent sound level

NEPA National Environmental Policy Act

PPV peak particle velocity

Program Coachella Valley-San Gorgonio Pass Rail Corridor Service Program

Program Corridor Coachella Valley-San Gorgonio Pass Rail Corridor

RCTC Riverside County Transportation Commission

ROW right-of-way

SDP Service Development Plan

SR State Route

U.S. United States

UP Union Pacific Railroad

VdB velocity in decibels 
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1 Introduction

The Federal Railroad Administration (FRA), California Department of Transportation (Caltrans) 

Division of Rail and Mass Transportation, and Riverside County Transportation Commission (RCTC) 

are proposing the Coachella Valley-San Gorgonio Pass Rail Corridor Service Program (Program) to 

establish daily intercity passenger rail service between Los Angeles Union Station (LAUS) in Los 

Angeles County, California and the City of Coachella in Riverside County, California. This noise and 

vibration technical memorandum evaluates potential noise and vibration effects along the 144-mile 

Coachella Valley-San Gorgonio Pass Rail Corridor (Program Corridor) in support of a programmatic 

Tier 1 Environmental Impact Statement (EIS)/Environmental Impact Report (EIR). The evaluation of 

potential noise and vibration effects resulting from the Program includes:

• Changes to noise compared with the No Build Alternative as a result of construction and 

operation of the Build Alternative Options

• Changes to vibration compared with the No Build Alternative as a result of construction and 

operation of the Build Alternative Options

1.1 Study Approach

This evaluation was prepared pursuant to the requirements of the National Environmental Policy Act 

(NEPA) and the California Environmental Quality Act (CEQA) and will be incorporated into the Tier 

1/Program EIS/EIR evaluation.

FRA, Caltrans, and RCTC are using a tiered NEPA/CEQA process (e.g., Tier 1/Program EIS/EIR) to 

complete the environmental review of the Program, under 40 Code of Federal Regulations 

1508.28 (titled “Tiering”), CEQA Guidelines Section 15168 (titled “Program EIR”), and 

Section 15170 (titled “Joint EIS/EIR”). “Tiering” is a staged environmental review process often 

applied to environmental review for complex transportation projects.
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The Tier 1/Program EIS/EIR, along with the concurrent preparation of the Service Development Plan 

(SDP), are the first steps in the tiered environmental review process. Based on the decisions made 

in the Tier 1/Program EIS/EIR and SDP, future site-specific proposals of infrastructure improvements 

will be evaluated through one or more Tier 2/Project-level environmental clearance processes. A 

description of the Tier 1/Program EIS/EIR, SDP, and Tier 2/Project-level analysis processes are 

further discussed below:

• Tier 1/Program EIS/EIR: The Tier 1/Program EIS/EIR evaluates potential environmental 

impacts of the No Build Alternative and three Build Alternative Options broadly within the 

Program Corridor. The Program Corridor provides a flexible regional context for the best 

location of an enhanced passenger rail system while providing opportunities for the Build 

Alternative Options to account for engineering and environmental constraints. The Tier 

1/Program EIS/EIR evaluation addresses broad questions and likely environmental effects 

within the Tier 1/Program EIS/EIR Study Area for specific environmental resources. The 

resource-specific study areas generally represent the potential area where rail infrastructure 

improvements and station facilities could be implemented and constructed but does not 

represent the precise location or footprint of the improvement or facility.

• SDP: The SDP defines the Program’s service mode, estimated ridership to include demand 

and revenue forecasts, operational strategy, station and access analysis, operating and 

maintenance costs, required infrastructure improvements and capital programming, and 

public benefits analysis necessary to implement the proposed intercity passenger rail 

service. As part of the SDP process, the site-specific infrastructure improvement 

requirements are being identified, including the number of stations and the general 

areas/communities in which stations might be located. The SDP infrastructure analysis is 

being informed by rail operations simulation modeling and would occur parallel to the Tier 

1/Program EIS/EIR evaluation process. 

• Tier 2 Project-Level Analysis: Based on the environmental evaluation conducted in the Tier 

1/Program EIS/EIR and the site-specific infrastructure improvements identified in the SDP, a 

Tier 2/Project-level analysis would be required. The Tier 2/Project-level analysis would be a 

separate environmental review potentially led and funded by an agency other than FRA. In 

addition, the Tier 2/Project-level analysis process would not automatically follow the 

Tier 1 process, rather the potential Tier 2 projects would need to be defined based on the 

Tier 1/Program EIS/EIR’s broad scope and funding. The Tier 2/Project-level analysis would 

closely align with the future preliminary engineering process and would analyze site-specific 

direct and indirect Project-level effects, in addition to any required permits, consultations, or 

approvals needed for construction.
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2 Program Location and Description 

2.1 Program Location

The Tier 1/Program EIS/EIR analyzes the No Build Alternative and three Build Alternative Options in 

two geographic sections—a Western Section and an Eastern Section—occurring within existing 

railroad rights-of-way (ROW), as shown on Figure 2-1 through Figure 2-3. The Program Corridor 

runs west-to-east, extending up to 144 linear miles from a western terminus at LAUS to an eastern 

terminus in either the City of Indio or City of Coachella (depending on the Build Alternative Option). 

From west to east, the cities traversed by the Build Alternative Options include Los Angeles, Vernon, 

Bell, Commerce, Montebello, Pico Rivera, Santa Fe Springs, Norwalk, La Mirada, Buena Park, 

Fullerton, Anaheim, Placentia, Yorba Linda, Chino Hills, Corona, Riverside, Grand Terrace, Colton, 

San Bernardino, Loma Linda, Redlands, Calimesa, Beaumont, Banning, Cabazon, Palm Springs, 

Cathedral City, Thousand Palms, Rancho Mirage, Palm Desert, Indio (under all Build Alternative 

Options), and/or Coachella (under Build Alternative Option 1 only). The boundary between Western 

and Eastern Sections is in the City of Colton, at the intersection of existing railroad lines owned by 

Union Pacific Railroad (UP) and BNSF. 

2.2 Program Description

2.2.1 Build Alternative Option 1 (Coachella Terminus)

Build Alternative Option 1 includes a total Program Corridor distance of 144 miles and consists of a 

Western Section, terminating at LAUS, and an Eastern Section, terminating in the City of Coachella. 

Western Section. Under Build Alternative Option 1, existing rail infrastructure would be used in the 

Western Section of the Program Corridor, and no additional railroad infrastructure improvements 

would be required. LAUS would serve as the western terminus, while existing stations in the Cities of 

Fullerton and Riverside would be utilized to support the proposed passenger rail service. No new 

stations or improvements to existing stations would be required to accommodate the proposed 

service within the Western Section of the Program Corridor.

Eastern Section. Under Build Alternative Option 1, potential new infrastructure improvements on the 

Eastern Section of the Program Corridor could include sidings, additional main line track, wayside 

signals, drainage, grade separation structures, and up to five new stations constructed in the 

following areas: 1) Loma Linda/Redlands Area (serving the Cities of Loma Linda and Redlands), 

2) the Pass Area (serving the communities of Beaumont, Banning, and Cabazon), 3) the Mid Valley 
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(serving the communities of Cathedral City, Thousand Palms, the Agua Caliente Casino area, 

Rancho Mirage, and Palm Desert), 4) the City of Indio, and 5) the City of Coachella as the eastern 

terminus of the Program Corridor.

2.2.2 Build Alternative Option 2 (Indio Terminus)

Build Alternative Option 2 includes a total Program Corridor distance of 140.25 miles and consists of 

a Western Section, terminating at LAUS, and an Eastern Section, terminating at the City of Indio.

Western Section. The Western Section under Build Alternative Option 2 would be the same as that 

described above under Build Alternative Option 1.

Eastern Section. Under Build Alternative Option 2, potential new infrastructure improvements on the 

Eastern Section of the Program Corridor could include sidings, additional main line track, wayside 

signals, drainage, grade separation structures, and up to four new potential stations could be 

constructed in the following areas: 1) Loma Linda/Redlands Area (serving the Cities of Loma Linda 

and Redlands), 2) the Pass Area (serving the communities of Beaumont, Banning, and Cabazon), 

3) the Mid Valley (serving the communities of Cathedral City, Thousand Palms, the Agua Caliente 

Casino area, Rancho Mirage, and Palm Desert), and 4) the City of Indio as the eastern terminus of 

the Program Corridor.

2.2.3 Build Alternative Option 3 (Indio Terminus with Limited Third 

Track)

Build Alternative Option 3 includes a total Program Corridor distance of 140.25 miles and consists of 

a Western Section, terminating at LAUS, and an Eastern Section, terminating at the City of Indio.

Western Section. The Western Section under Build Alternative Option 3 would be the same as that 

described above under Build Alternative Options 1 and 2.

Eastern Section. The Eastern Section under Build Alternative Option 3 would be the same as that 

described above under Build Alternative Option 2, except for the following changes:

As part of Build Alternative Option 3, additional infrastructure improvements for the Eastern Section 

of the Program Corridor have been considered. These potential infrastructure improvements include 

the addition of station tracks and a third main line track. The addition of station tracks would be the 

same as described under Build Alternative Options 1 and 2; however, the addition of the third main 

track would be limited under Build Alternative Option 3 when compared with Build Alternative 

Options 1 and 2. The limited third track under Build Alternative Option 3 would augment the existing 

two main tracks along the Eastern Section of the Program Corridor to the proposed Mid Valley 

Station Area.
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2.3 Construction

2.3.1 Western Section

In the Western Section, existing rail infrastructure would be used to accommodate the proposed 

service, and no additional track improvements would be required to accommodate the proposed 

service under all Build Alternative Options. LAUS would serve as the western terminus, and existing 

stations in the Cities of Fullerton and Riverside would be used, as depicted on Figure 2-1. No new 

stations or additions to existing stations would be required to accommodate the proposed service

under all Build Alternative Options. The Tier 1/Program EIS/EIR Study Area for potential 

construction-related impacts on noise and vibration within the Western Section is up to 600 feet from 

either side of the existing railroad centerline.

2.3.2 Eastern Section

In the Eastern Section, proposed new infrastructure improvements under all Build Alternative 

Options could include sidings, additional main line track, wayside signals, drainage, 

grade-separation structures, and stations to accommodate the proposed service. The Eastern 

Section would use the existing station in the City of Palm Springs, which is the only existing station 

in the Eastern Section. Additionally, as depicted on Figure 2-2 and Figure 2-3, up to five new 

potential stations could be constructed in the following areas: 1) Loma Linda/Redlands Area (serving 

the Cities of Loma Linda and Redlands), 2) the Pass Area (serving the communities of Beaumont, 

Banning, and Cabazon), 3) the Mid-Valley (serving the communities of Cathedral City, Thousand 

Palms, the Agua Caliente Casino area, Rancho Mirage, and Palm Desert), 4) the City of Indio (under 

all Build Alternative Options), and/or 5) the City of Coachella (under Build Alternative Option 1 only).

The Tier 1/Program EIS/EIR Study Area for potential construction-related impacts on noise and 

vibration within the Eastern Section is up to 1,000 feet from either side of the centerline, plus a 

500-foot buffer for the assessment of indirect impacts, for a total Tier 1/Program EIS/EIR Study Area 

of 1,500 feet from either side of the centerline at each of the individual station location areas. The 

remaining portion of the Eastern Section Tier 1/Program EIS/EIR Study Area encompasses up to 

300 feet from the railroad centerline to include non-station-related infrastructure improvements, plus 

a 500-foot buffer for the assessment of indirect impacts, for a total Tier 1/Program EIS/EIR Study 

Area of 800 feet from the railroad centerline.
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2.4 Operation

Passenger train frequencies proposed as part of the Program would consist of the addition of two 

daily round-trip intercity diesel-powered passenger trains operating the entire length of the Program 

Corridor between Los Angeles and Indio and/or Coachella, with one morning departure and one 

afternoon departure from each end of the Program Corridor.
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Figure 2-1. Western Section of the Program Corridor (Build Alternative Options 1, 2, and 3)
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Figure 2-2. Eastern Section of the Program Corridor (Build Alternative Option 1)
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Figure 2-3. Eastern Section of the Program Corridor (Build Alternative Options 2 and 3)
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3 Regulatory Framework

In accordance with NEPA (42 United States [U.S.] Code Section 4321 et seq.), CEQ regulations 

implementing NEPA (40 Code of Federal Regulations Parts 1501 1508), FRA’s Procedures for 

Considering Environmental Impacts (64 Federal Register 28545, May 26, 1999) and CEQA, FRA 

identified potential noise-sensitive land uses within the Tier 1/Program EIS/EIR Study Area and 

evaluated the potential impacts that could occur from implementation of the Build Alternative 

Options. Federal and local guidelines for environmental noise and vibration relevant to the Tier 

1/Program-level analysis are described in this section. The thresholds of significance used for 

assessment of noise and vibration effects are discussed in Section 6, Environmental Consequences.

3.1 Federal

3.1.1 Environmental Protection Agency

In 1974, the U.S. Environmental Protection Agency (EPA) published Information on Levels of 

Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate Margin of 

Safety, a comprehensive document that identifies noise levels to protect public health and welfare 

against hearing loss, annoyance, and activity interference (U.S. EPA 1974).

In response to the requirements of the Noise Control Act, U.S. EPA identified indoor and outdoor 

noise limits to protect public health and welfare. U.S. EPA identified outdoor day-night average 

sound level (Ldn) limits of 55 decibels (dB) and indoor Ldn limits of 45 dB as desirable for protecting 

against speech interference and sleep disturbance in residential areas and at educational and health 

care facilities. The sound-level criterion for protecting against hearing damage in commercial and 

industrial areas is identified as the 24-hour equivalent sound level (Leq) value of 70 dB (both 

outdoors and indoors). Based on attitudinal surveys, U.S. EPA determined that a 5 dB increase in 

Ldn or Leq could result in a change in community reaction (U.S. EPA 1974). Ldn and Leq are described 

in further detail in Appendix A, Fundamental Concepts of Environmental Noise.

The Noise Control Act also directed federal agencies to comply with applicable federal, state, 

interstate, and local noise control regulations. Although U.S. EPA was given a major role in 

disseminating information to the public and coordinating with federal agencies, each federal agency 

retained authority to adopt noise regulations pertaining to its programs. U.S. EPA can require federal 

agencies to justify their noise regulations in terms of Noise Control Act policy requirements. 

The following key federal agencies have adopted noise regulations and standards:

• Housing and Urban Development: Noise standards for federally funded housing projects
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• Federal Aviation Administration: Noise standards for aircraft

• Federal Highway Administration: Noise standards for federally funded highway projects

• Federal Transit Administration (FTA): Noise standards for federally funded transit projects

• FRA: Noise standards for federally funded rail projects

3.1.2 Federal Railroad Administration/Federal Transit Administration 

Noise Impact Criteria

According to the FRA’s Procedures for Considering Environmental Impacts (64 Federal Register

28545, May 26, 1999) Section 14(n)(13) (FRA 1999a), an “EIS should assess the impacts on both 

passenger and freight transportation, by all modes, from local, regional, national, and international 

perspectives. The EIS should include a discussion of both construction period and long-term impacts 

on vehicular traffic congestion.”

The FRA and the FTA have published impact assessment procedures and criteria pertaining to 

noise. Consistent with a Tier 1/Program EIS/EIR assessment, guidance by these agencies will be 

considered in the evaluation of noise and vibration associated with the Build Alternative Options. 

Assessment of noise and vibration impacts associated with the Program is based on guidance in the 

FTA Transit Noise and Vibration Impact Assessment Manual (FTA Manual) (FTA 2018). The FTA 

Manual is used for rail projects where conventional train speeds are below 90 miles per hour (FRA

2012). Therefore, FRA conventional rail projects generally use noise and vibration assessment 

guidance from the FTA Manual. The FTA Manual also includes assessment methods for noise and 

vibration from construction.

Construction

FTA has developed methods for evaluating construction noise levels, which are discussed in the 

FTA Manual. The FTA Manual does not contain standardized criteria for assessing construction 

noise impacts. Instead, it includes guidelines for suggested noise limits for residential uses exposed 

to construction noise to describe levels that may result in an adverse community reaction. These 

guidelines are summarized in Table 3-1.
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Table 3-1. Federal Transit Administration Construction Noise Impact Guidelines

Land Use 8-hour Leq (dBA), Day 8-hour Leq (dBA), Night

Residential 80 70

Commercial 85 85

Industrial 90 90

Source: FTA 2018

Notes:

dBA=A-weighted decibel; Leq=equivalent sound level

Thresholds for construction noise may be set at the local level, as described in Section 3.3,

according to the expected hours of equipment operation and the noise limits specified in the noise 

ordinances of the applicable jurisdictions.

Rail Operations

FRA published and implemented impact assessment procedures and criteria pertaining to noise. 

According to the High-Speed Ground Transportation Noise and Vibration Impact Assessment

(FRA 2012), the FTA Manual is used for rail projects where conventional train speeds are below 

90 miles per hour; as such, FRA generally uses noise and vibration guidance from the FTA Manual.

Therefore, noise and vibration impacts associated with operation of the Build Alternative Options are 

based on guidance in the FTA Manual.

The FTA Manual describes the noise impact criteria that have been adopted to assess noise 

contributions and potential impacts on the existing environment from rapid transit sources. The noise 

impact criteria defined in the FTA Manual are based on an objective that calls for maintaining a noise 

environment that is considered acceptable for noise-sensitive land uses. 

For assessing noise from transit operations, FTA defines three land use categories.

• Category 1: Tracts of land where quiet is an essential element of their intended purpose, 

such as outdoor amphitheaters, concert pavilions, and national historic landmarks with 

significant outdoor use.

• Category 2: Residences and buildings where people normally sleep, including homes, 

hospitals, and hotels. 

• Category 3: Institutional land uses (e.g., schools, places of worship, libraries) that are 

typically available during daytime and evening hours. Other uses in this category can include 

medical offices, conference rooms, recording studios, concert halls, cemeteries, monuments, 

museums, historical sites, parks, and recreational facilities. 
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Noise exposure values are reported as the Ldn average sound level for residential land uses 

(Category 2) or, the equivalent sound level over a 1-hour A weighted equivalent sound level (Leq(h))

for other land uses (Categories 1 and 3). Commercial and industrial uses are not included in the vast 

majority of cases because they are generally compatible with higher noise levels. Exceptions include 

commercial land uses with a feature that receives significant outdoor use, such as a playground, or 

uses that require quiet as an important part of their function, such as recording studios.

In the FTA Manual, noise impact criteria for operation of rapid transit facilities consider a project’s 

contribution to existing noise levels, using a sliding scale, according to the land uses affected. The 

criteria correspond to heightened community annoyance because of the introduction of a new transit 

facility relative to existing ambient noise conditions.

Noise impacts are assessed by comparing existing outdoor exposures with future project-related 

outdoor noise levels, as depicted on Figure 3-1. The criterion for each degree of impact is based on 

a sliding scale that is dependent on the existing noise exposure and the increase in noise exposure 

because of a project. 
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Figure 3-1. Federal Transit Administration Noise Impact Criteria 

Source: FTA 2018.

The noise impact categories are as follows:

• No Impact: A project, on average, would result in an insignificant increase in the number of 

instances where people are “highly annoyed” by new noise. 

• Moderate Impact: The change in cumulative noise is noticeable to most people but may not 

be enough to cause strong adverse community reactions.

• Severe Impact: A significant percentage of people would be highly annoyed by the noise, 

perhaps resulting in vigorous community reaction. 
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A project’s noise contribution relative to the existing noise levels, as depicted on Figure 3-1, differs 

according to the level of existing noise exposure. For example, a project contribution of 

59 A-weighted decibels (dBA) Ldn would be considered a severe impact at a Category 2 receptor 

with an existing noise exposure of up to 50 dBA Ldn (a difference of 9 dB), whereas a project 

contribution of 69 dBA Ldn would result in a severe impact at a Category 2 receptor with an existing 

noise exposure of up to 70 dBA Ldn (a difference of 1 dB). The impact curves on Figure 3-1 are 

based on community increases in cumulative noise exposure relative to existing conditions, as 

depicted on Figure 3-2. The justification for the sliding scale depicted in these figures recognizes that 

people who are already exposed to high levels of noise in the ambient environment are expected to 

tolerate small increases in noise in their community according to the level of their existing noise 

exposure.

Figure 3-2. Increase in Cumulative Noise Levels Allowed by Criteria

Note: Noise exposure increase impact curves are adjusted by +5 dB for Category 3 land uses.

3.1.3 Federal Transit Administration Vibration Impact Criteria

General Vibration Effects

The FTA vibration impact criteria for the land use categories described above are depicted in

Table 3-2. The criteria are based on the frequency of events and related to ground-borne vibration 

that can cause human annoyance or interfere with the use of vibration-sensitive equipment. The 
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criteria for acceptable ground-borne vibration are based on the maximum vibration level (Vdb) for a 

single event and expressed in terms of root-mean-square velocity level.

Table 3-2. Ground-borne Vibration Impact Criteria for General Assessment

Land Use Category

Vibration Impact 

Levels for Frequent 

Eventsa

(VdB re 1 

micro-inch/second)

Vibration Impact 

Levels for Occasional 

Eventsb

(VdB re 1 

micro-inch/second)

Vibration Impact 

Levels for Infrequent 

Eventsc

(VdB re 1 

micro-inch/second)

Category 1:

Buildings where vibration would 

interfere with interior operations

65 VdBd65 VdBd65 VdBd

Category 2:

Residences and buildings where 

people normally sleep

72 VdB 75 VdB 80 VdB

Category 3:

Institutional land uses with 

primarily daytime use

75 VdB 78 VdB 83 VdB

Source: FTA 2018

Notes:

a The term frequent events is defined as more than 70 vibration events from the same source each day. Most rapid 

transit projects fall into this category. 

b The term occasional events is defined as between 30 and 70 vibration events from the same source each day. 

Most commuter trunk lines have operations in this range. 

c The term infrequent events is defined as fewer than 30 vibration events of the same kind each day. This category 

includes most commuter rail branch lines. 

d This criterion limit is based on levels that are acceptable for most moderately sensitive equipment, such as optical 

microscopes. Vibration-sensitive manufacturing or research will require detailed evaluation to define the acceptable 

vibration levels. Ensuring lower vibration levels in a building often requires special design of the heating, ventilation, and 

air-conditioning systems and stiffened floors. 

VdB=velocity in decibels

Potential for Damage to Fragile Structures

FTA analysis guidelines call for an investigation of the potential for vibration-induced damage to 

“fragile” or “extremely fragile” buildings (FTA 2018). Damage to a building is possible (but not 

necessarily probable) if ground-borne vibration levels exceed the following criteria:

• A 0.20-inch-per-second peak particle velocity (PPV) (approximately 100 velocity in decibels 

[VdB]) for non-engineered timber and masonry buildings

• A 0.12-inch-per-second PPV (approximately 95 VdB) for buildings that are extremely 

susceptible to vibration damage
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Ground-borne Noise

At higher frequencies, ground-borne vibration can be perceived as a noise source. At sufficiently 

high amplitudes, the propagation of vibration waves through the ground can couple with building 

elements and cause them to vibrate at a frequency that is audible to the human ear. 

Ground-borne noise could rattle windows, walls, or other items that are coupled to building surfaces. 

Ground-borne vibration levels that result in ground-borne noise are often experienced as a 

combination of perceptible vibration and low-frequency noise. 

Ground-borne noise is normally not a consideration when rail transit sources are at-grade. 

Ground-borne noise generally becomes an important consideration for subterranean rail transit or 

other projects in which part of the alignment includes a tunnel. Ground-borne noise impacts are not 

anticipated for the Build Alternative Options.

3.1.4 Noise Control Act of 1972

The Noise Control Act of 1972 (Public Law 92 574) established a requirement for all federal 

agencies to administer their programs in a manner that promotes an environment that is free of 

noise that jeopardizes public health or welfare. U.S. EPA was assigned the following responsibilities:

• Providing information to the public regarding the identifiable effects of noise on public health 

and welfare

• Publishing information on the levels of environmental noise to protect the public health and 

welfare with an adequate margin of safety

• Coordinating federal research and activities related to noise control

• Establishing federal noise emission standards for selected products distributed in interstate 

commerce

3.2 State

3.2.1 California Noise Control Act

The California Noise Control Act was enacted in 1973. In preparing its general plan noise element, a 

city or county must identify local noise sources and analyze and quantify to the extent practicable 

current and projected noise levels from various sources, including highways and freeways; 

passenger and freight railroad operations; ground rapid transit systems; commercial, general, and 

military aviation and airport operations; and other stationary ground noise sources. 
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The State of California General Plan Guidelines (Governor’s Office of Planning and Research 2003) 

provide noise compatibility guidelines for land use planning, according to the existing community 

noise level; however, these guidelines offer no information regarding construction noise. The state 

has also published its Model Community Noise Ordinance (California Office of Noise Control 1977), 

which provides guidance to cities and counties on how to develop a community noise ordinance. 

These guidelines include recommended limits on construction noise levels; however, these are only 

guidelines and are not enforceable. 

California Department of Transportation Vibration Standards

For continuous/frequent intermittent sources, such as pile driving, Caltrans recommends a 

0.25-inch-per-second PPV threshold for “historic and some old buildings” and a PPV of 0.3 inch per 

second for “older residential structures” (Caltrans 2004). These criteria are directed primarily toward, 

but not limited to, all construction related to pile driving, demolition, and pavement-breaking 

activities.

3.3 Local/Regional

The Program Corridor passes through many local jurisdictions. The Program Corridor extends 

through the counties of Los Angeles, Orange, San Bernardino, and Riverside and the cities of Los 

Angeles, Vernon, Bell, Commerce, Montebello, Pico Rivera, Santa Fe Springs, Norwalk, La Mirada, 

Buena Park, Fullerton, Anaheim, Placentia, Yorba Linda, Chino Hills, Corona, Riverside, Grand 

Terrace, Colton, San Bernardino, Loma Linda, Redlands, Calimesa, Beaumont, Banning, Cabazon, 

Palm Springs, Cathedral City, Thousand Palms, Rancho Mirage, Palm Desert, Indio, and Coachella. 

Many of these jurisdictions have noise standards that relate to land use compatibility with 

transportation noise sources (e.g., traffic, rail, aircraft); however, noise from transit sources is 

controlled at the federal level, not at the local level. 

Noise ordinances applicable to the jurisdictions within the Tier 1/Program EIS/EIR Study Area do not 

apply noise limits to transportation sources but, rather, to non-transportation sources, such as 

construction equipment. In many cases, jurisdictions provide exemptions from noise ordinance 

standards for temporary construction work or necessary infrastructure repairs or improvements. In 

many cases, construction work during daytime hours is exempt from local regulations.
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4 Methodology

This section describes methods and approaches for the evaluation of noise and vibration from 

construction and operation of the Build Alternative Options. Because this analysis was conducted at 

a Tier 1/Program EIS/EIR service evaluation level, a screening-level noise and vibration impact 

assessment was completed rather than a detailed quantitative evaluation of noise and vibration 

levels. Detailed quantitative analysis would occur during Tier 2/Project-level analysis.

4.1 Noise

4.1.1 Construction Noise

The thresholds used in the evaluation were based on guidance from the FTA Manual (FTA 2018). 

Although construction noise may be exempt from daytime noise standards in local jurisdictions, FTA 

guidance should be used to minimize the potential for noise complaints. These thresholds are 

standard criteria for assessment of transit projects under FTA and are appropriate, given federal 

involvement in the Program. Thresholds for construction in local jurisdictions, if more stringent, 

would be addressed in a Tier 2/Project-level analysis. In many cases, local jurisdictions do not 

regulate daytime construction noise, and thus, FTA daytime standards are often used to determine 

potential for community annoyance during construction. As such, local ordinances were not 

evaluated for potential noise effects under the Tier 1/Program EIS/EIR evaluation. FTA guidelines for 

temporary construction, described below, provide a reasonable set of indicators that can be used as 

impact thresholds for the Tier 1/Program EIS/EIR evaluation.

Noise levels produced by commonly used construction equipment are summarized in 

Table 4-1. Individual types of heavy construction equipment are expected to generate noise levels 

ranging from 74 to 89 dBA at a distance of 50 feet. Given construction requirements, pile drivers 

could be used. Pile drivers typically generate a maximum noise level of up to 101 dBA at a distance 

of 50 feet. The construction noise level at a given receptor would depend on the type of construction 

activity, the noise level generated by that activity, and the distance and shielding between the activity 

and the noise-sensitive receptor.

Utilization factors for construction noise are used in the evaluation to describe source noise levels in 

terms of Leq noise exposure, as outlined in the FTA guidelines for construction noise. The Leq noise 

standard accounts for the energy average of noise over a specified interval (e.g., 1 hour or 8 hours); 

therefore, a utilization factor represents the amount of time a specific type of equipment is used 

during the interval.
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Table 4-1. Construction Equipment Noise Emission Levels

Equipment

Typical Noise Level (dBA)

50 feet from Source Typical Utilization Factors (minutes)

Grader 85 40

Bulldozer 85 40

Truck 88 40

Loader 85 40

Compactor 82 20

Backhoe 80 40

Crane 83 20

Roller 74 50

Paver 89 50

Excavator 85 40

Pile Driver (Impact) 101 20

Pile Driver (Sonic) 96 20

Sources: FTA 2018; Thalheimer 2000

Notes:

dBA=A-weighted decibel

Based on FTA guidance, a construction noise impact may occur if construction equipment exceeds 

80 dBA Leq (8 hours) at a residential location between the hours of 7:00 a.m. and 10:00 p.m. or 

70 dBA Leq (8 hours) between the hours of 10:00 p.m. and 7:00 a.m. 

4.1.2 Operational Noise

Train Operations

The rail noise model focuses on land uses that could be subject to Program-related transit noise 

impacts. Although all developed land uses were evaluated in this analysis, the focus of the impact 

evaluation was on outdoor locations with frequent human use, institutional land uses, and residential 

buildings where people normally sleep. 

The noise and vibration assessment was conducted in accordance with FTA Manual guidelines. The 

FTA Manual specifies that criteria are to be applied to compare future project noise with existing 

noise, rather than future project noise with projections of future “no-build” noise exposure.
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Existing noise levels for receptor locations were derived from projected daily freight and intercity 

passenger, and commuter rail trips along the existing Program Corridor, described in Section 5. 

Given the high density of residential uses along much of the Program Corridor, existing noise levels 

from rail were calculated by adjusting for varying distances between noise-sensitive receptors and 

noise sources. The primary sources of noise along the Program Corridor were assumed to consist of 

either wayside noise from train passbys or grade crossings where trains are required to sound horns 

as they approach within 0.25 mile of the crossing. Geographic information system analysis was used 

to identify potentially affected parcels along the Program Corridor with the addition of two daily 

round-trip intercity diesel-powered passenger trains operating the entire length of the Program 

Corridor under Build Alternative Options 1, 2, and 3.

The noise model was based on FTA single-event source levels for train vehicles and horns, as 

defined in the FTA Manual. For the Tier 1/Program EIS/EIR, the FTA General Assessment method 

was used to determine projected future project-induced noise and vibration levels as a function of 

distance and to identify impacts on noise-sensitive receivers. Noise contributions from rail vehicles

under the Build Alternative Options were calculated using the noise source levels for at-grade rail 

transit vehicles operating on welded rail, as outlined in the FTA Manual. Calculated noise levels 

associated with the Build Alternative Options were then compared with “moderate impact” and “severe 

impact” criteria according to existing ambient levels at a given receptor location, as described in 

Section 3.1.3.

A noise impact is considered to occur at a receptor location if the increased noise exposure for the 

receptor’s applicable land use category (Category 1, 2, or 3) is equal to or exceeds the FTA criterion 

for “moderate impact” or “severe impact,” as indicated on Figure 3-1, based on the existing noise 

exposure for the receptor. The Program assumes track configuration would be the same under both 

existing and future conditions as the Build Alternative Options’ route alternatives would use the 

existing railroad ROW; therefore, the focus of the evaluation was on the overall increase in daily train 

trips (two daily round-trips per day trips per day). The impact criteria are described in detail in 

Section 3.

Traffic 

The Build Alternative Options were not estimated to result in any substantial capacity or operational 

improvements to existing traffic facilities. Changes in traffic noise, as a result of the Build Alternative 

Options, were based on anticipated changes in ridership because of the Program and subsequent 

potential effects on traffic noise levels.
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A traffic noise impact is considered to occur where the increase in traffic volume on a given road 

segment would result in a 3 dBA increase relative to existing conditions. A traffic noise increase of 

3 dBA is generally barely perceptible, while a 5 dBA increase is clearly noticeable (Caltrans 2009).

4.2 Vibration

4.2.1 Construction Vibration

Ground-borne vibration during construction of the Build Alternative Options was analyzed using the 

methodology discussed in Chapter 12 of the FTA Manual. The vibration source levels for typical 

construction equipment types, as depicted in Table 4-2, are expressed in terms of PPV in inches per 

second at a reference distance of 25 feet from the source and root-mean-square VdB at 25 feet. For 

this evaluation, a vibratory roller (source vibration level of 0.210 inch per second PPV) was identified 

as the piece of non-impact equipment that could produce the highest vibration levels. 

Impact-producing equipment types, such as pile drivers, are a substantial source of vibration, as 

depicted in Table 4-2. 

Table 4-2. Typical Construction Equipment Vibration Levels

Equipment Range

PPV at 25 Feet

(inch/second)

Vibration Level at 25 Feet, VdB 

(approximate)

Pile driver (impact) Upper range 1.518 112

Pile driver (impact) Typical 0.644 104

Pile driver (sonic) Upper range 0.734 105

Pile driver (sonic) Typical 0.170 93

Clam shovel drop 

(slurry wall)

— 0.202 94

Vibratory roller — 0.210 94

Large bulldozer — 0.089 87

Loaded truck — 0.076 86

Jackhammer — 0.035 79

Small bulldozer — 0.003 58

Source: FTA 2018

Notes:

PPV=peak particle velocity (inch per second); VdB=vibration velocity decibels
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Vibration from construction equipment could cause damage to architectural resources adjacent to 

the Build Alternative Options’ route alternatives. The potential for building damage was determined 

by using FTA methodology, including the damage potential vibration thresholds described under 

FTA Vibration Impact Criteria in Section 3.

A construction-related vibration impact is considered to occur if vibration levels from construction 

equipment are perceptible at a receiving residential land use (i.e., 75 VdB, described as the 

annoyance impact criterion for “occasional events” at Category 2 land uses, depicted in Table 3-2). 

A vibration impact resulting in building damage could occur at a PPV of 0.20 inch per second. This is 

based on the FTA criterion for fragile buildings. 

4.2.2 Operational Vibration

The FTA procedure for a general vibration assessment was used for the evaluation of ground-borne 

vibration levels from trains within the Program Corridor. For the operational vibration evaluation, the 

number of daily events was classified under the FTA category of “frequent events” for the Western 

Section, which corresponds to more than 70 vibration events from freight, intercity passenger, and 

commuter trains per day, as defined in Table 3-2. For the Eastern Section, the number of daily 

events was classified under the FTA category of “occasional events,” which corresponds to between 

30 and 70 vibration events from freight and intercity passenger trains per day. Land use 

designations for Category 2 (residences and lodging facilities) and Category 3 (institutional use) 

were used in the evaluation. 

Vibration source levels were derived from the FTA Manual using the generalized surface vibration 

curve for locomotive-powered passenger or freight vehicles. Soil propagation characteristics were 

assumed to be normal. For the generalized ground surface vibration curve, root-mean-square

velocity-level data at the receptor were used, with the distance of interest adjusted according to 

vehicle speed (a maximum of 79 miles per hour was assumed throughout the Program Corridor),

wheel condition (normal), track condition (normal), track treatments, and the number of floors above 

grade to receptor locations. Vibration-level adjustments for special track work were applied as 

applicable in areas adjacent to vibration-sensitive land uses.

Ground-borne vibration impact criteria for the FTA general assessment were used to assess 

vibration impacts from train operations. Impacts would be triggered at a vibration-sensitive location if 

future vibration levels were to exceed the FTA general assessment criteria under FTA Vibration 

Impact Criteria in Section 3, and predicted future vibration levels were to exceed existing vibration 

levels by 3 VdB or more.
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4.3 Tier 1/Program EIS/EIR Study Area

The Tier 1/Program EIS/EIR Study Area for noise includes land uses that could be subject to 

Program-related transit noise impacts. Although all developed land uses were evaluated in this 

analysis, the focus of the impact evaluation was on outdoor locations with frequent human use, 

institutional land uses, and residential buildings where people normally sleep.
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5 Existing Conditions

5.1 Physical Setting

5.1.1 Noise- and Vibration-Sensitive Land Uses

The Program Corridor crosses a large geographic area within Southern California, spanning 

approximately 144 miles from its western terminus in Los Angeles to its eastern terminus in Indio or 

Coachella. The Program Corridor occurs within an existing railroad corridor that traverses areas that 

have predominately been heavily modified for urban purposes, especially in the Western Section, 

although some areas occur in, or adjacent to, lands that are in a natural condition. Much of the 

Program Corridor from Los Angeles to Redlands is urbanized. The Eastern Section of the Program 

Corridor east of Colton is less urbanized with vacant land comprising of the largest land use 

category. 

Build Alternative Option 1 (Coachella Terminus)

Almost the entire Western Section of the Program Corridor passes through highly developed urban 

and suburban areas, including many areas with adjacent sensitive land uses, such as residences 

(Category 2), schools (Category 3), and other institutional uses (Category 3). The Western Section 

also extends through many commercial and industrial areas, which are generally not noise sensitive 

unless they are associated with areas of frequent outdoor use. 

The Eastern Section of the Program Corridor is highly developed in many locations, but also passes 

through sparsely populated rural areas and open space areas, including a large wind farm west of 

Palm Springs. There are several single- and multifamily residences (Category 2), lodging uses 

(Category 2), churches (Category 3), schools (Category 3), and other institutional uses (Category 3) 

within the Program Corridor. No Category 1 land uses were identified within the Program Corridor. 

Additional details related to land use within the Program Corridor, parks and schools located within 

the Program Corridor, and potentially historic buildings (which may be affected by vibration) are 

provided in Section 3.2, Land Use and Planning; Section 3.13, Cultural Resources; and Section 

3.14, Parklands and Community Services, of the Tier 1/Program EIS/EIR. 
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Build Alternative Option 2 (Indio Terminus)

Distribution of existing land uses within the Western Section of the Program Corridor under Build 

Alternative Option 2 are the same as Build Alternative Option 1; however, there are fewer acres of 

land within the Program Corridor under Build Alternative Option 2 because of the shorter route 

alignment and reduced station options. Build Alternative Option 2 still contains several single- and 

multifamily residences (Category 2), lodging uses (Category 2), churches (Category 3), schools 

(Category 3), and other institutional uses (Category 3) within the Eastern Section. 

Build Alternative Option 3 (Indio Terminus with Limited Third Track)

Potential sensitive land uses within the Program Corridor under Build Alternative Option 3 are the 

same as those identified for Build Alternative Option 2. 

5.1.2 Existing Noise and Vibration Sources

The urban setting that constitutes most of the Western Section of the Program Corridor contains a 

mix of transportation and stationary noise sources associated with a highly developed area. Within 

the Eastern Section of the Program Corridor, there is a mix of urban, suburban, and rural areas that 

contain a similar mix of transportation and stationary noise sources. Noise from freeway and local 

traffic, transit, aircraft, heavy equipment, and industrial and commercial sources contribute to 

ambient noise along the Program Corridor. Train and traffic operations are assumed to be primary 

contributors to ambient noise in the Tier 1/Program EIS/EIR Study Area. The different types of train 

and traffic sources that contribute to ambient noise along the Program Corridor are discussed below.

Train Operations

Table 5-1 presents existing train operations from the three host railroads (host railroads have 

ownership and operating rights to the railroad sections) along the Program Corridor for all Build 

Alternative Options – Union Pacific Railroad, BNSF, and Southern California Regional Rail Authority 

(Metrolink). Operations vary considerably by segment; however, both the Western and Eastern 

Sections of the Program Corridor have high-density, multiple-track main lines that support freight 

and passenger rail operations, which contribute to existing noise and vibration levels in the Tier 

1/Program EIS/EIR Study Area. The highest density segment in the Western Section is between Los 

Angeles and Fullerton and has an average of 86 daily trains, while the lowest density segment is 

between Fullerton and Atwood and has an average of 43 daily trains. The Eastern Section averages

43 daily trains along the Colton-Coachella segment, consisting of freight and passenger trains.
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Table 5-1. Existing Year (2018) Daily Train Operations within Program Corridor (One-Way Trips) 

Endpoints

Eastbound

Commuter 

Trains 

(SCRRA)

Westbound

Commuter 

Trains 

(SCRRA)

Eastbound

Intercity 

Trains

(Amtrak, 

Pacific 

Surfliner)

Westbound

Intercity 

Trains

(Amtrak, 

Pacific 

Surfliner)

Eastbound

Long 

Distance 

Passenger 

Trains 

(Amtrak)

Westbound

Long 

Distance 

Passenger 

Trains 

(Amtrak)

Eastbound

Freight 

Trains 

(UP, BNSF)

Westbound

Freight 

Trains 

(UP, BNSF)

Total 

Average 

Daily 

Volume 

of 

Trains

Western Section (SCRRA – Host Railroad; Additional Operators – Amtrak, BNSF)

Los Angeles

(Union Station-Soto)a

14 14 12 12 1 1 0.5 0.5 55

Western Section (BNSF – Host Railroad; Additional Operators – Amtrak, SCRRA, UP)

Los Angeles (Soto)a –

Fullerton

14 14 12 12 1 1 16 16 86

Fullerton-Atwood 5 4 0 0 1 1 16 16 43

Atwood-Riverside 13 12 0 0 1 1 17 17 61

Riverside-Highgrove 10 10 0 0 1 1 27 27 76

Highgrove-Colton 4 4 0 0 1 1 27 27 64

Eastern Section (UP – Host Railroad; Additional Operator – Amtrak)

Colton-Coachella 0 0 0 0 0.5 0.5 21 21 43

Notes: 

Daily train counts represent revenue train movements on a weekday (Monday-Friday). Freight train counts are based on Base Year (2013) daily freight train totals for 

the line segments shown above, as published in the 2018 California State Rail Plan, Appendix A.4, Table 20. Passenger and commuter train counts are based on the 

following public timetables in effect in September 2018: Metrolink “All Lines” timetable effective May 14, 2018, the 2018 LOSSAN Southern California Passenger Rail 

System Map and Timetables effective April 1, 2018, the Amtrak Southwest Chief timetable effective July 31, 2018, and the Amtrak Sunset Limited timetable effective 

March 11, 2018. 

* Soto interlocking (Milepost 144.4) in Los Angeles

LOSSAN=Los Angeles-San Diego-San Luis Obispo; SCRRA=Southern California Regional Rail Authority; UP=Union Pacific Railroad
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Metrolink operates commuter trains in the Western Section and provides primarily peak-hour service 

to and from Los Angeles. Three different Metrolink commuter rail lines use some portion of the 

Western Section. Metrolink 91/Perris Valley Line trains operating between Los Angeles, Riverside, 

and Perris serve commuter rail stations in the Western Section between Los Angeles and 

Highgrove. Metrolink Orange County Line trains operating between Los Angeles and Oceanside 

serve commuter rail stations in the Western Section between Los Angeles and Fullerton. Metrolink 

Inland Empire-Orange County Line trains operating between Oceanside and San Bernardino serve 

commuter rail stations in the Western Section between Atwood (east of Fullerton) and Colton under 

Build Alternative Options 1, 2, and 3. These account for up to 50 one-way trips per day along some 

portion of the Western Section (a fourth Metrolink commuter line, the Riverside Line operating 

between Los Angeles and Riverside uses an alternate, parallel freight line between its two endpoints 

but shares common stations with 91 Line/Perris Valley Line trains at Los Angeles and 

Riverside-downtown).

Intercity passenger service is provided by Amtrak, which operates two types of trains in the Program 

Corridor, state-supported regional passenger trains and long-distance trains. The state-supported 

Pacific Surfliner trains operating between San Luis Obispo, Los Angeles, and San Diego serve 

Amtrak stations in the Western Section of the Program Corridor at Los Angeles and Fullerton. These 

account for 24 one-way trips per day in the Western Section. Amtrak’s Southwest Chief 

long-distance train, operating between Los Angeles and Chicago, serves Amtrak stations in the 

Western Section at Los Angeles, Fullerton, and Riverside. This train accounts for two one-way trips 

per day along the Western Section of the Program Corridor.

Amtrak also operates one long-distance passenger train in the Eastern Section of the Program 

Corridor. The Sunset Limited train operating between Los Angeles and New Orleans serves the 

existing Amtrak station in the Eastern Section at Palm Springs. This train operates three days per 

week in each direction and accounts for 0.5 one-way trips per day along the Eastern Section.

Passenger trains, such as commuter and intercity trains, are operated on specific schedules and 

operate at higher maximum authorized speeds than freight trains using the Program Corridor. The 

number of freight trains per day, and their days and times of operation, can vary depending on 

customer requirements, including volumes at the ports of Los Angeles and Long Beach.1

1 The evaluation in Table 5-1 assumes that freight trains would consist of an average of three locomotives and 75 

cars each.
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Freight and commuter trains are required to sound horns within 0.25 mile of grade crossings. This 

safety measure warns motor vehicle operators of an approaching train and is required under FRA 

regulations. Several grade crossings along the Western and Eastern sections are located near 

noise-sensitive uses.

Highways and Local Roads

Traffic noise from cars and trucks is a primary source of ambient noise in the Tier 1/Program 

EIS/EIR Study Area. Many highways and local roads serve commuter and heavy trucking demands 

in both the Western and Eastern Sections of the Program Corridor. Heavy trucks and buses are 

intermittent sources of vibration on local roads.

In the Western Section of the Tier 1/Program EIS/EIR Study Area, the three most important east to 

west regional highways include Interstate (I) 10, State Route (SR) 60, and SR 91. 

In the Eastern Section, the Tier 1/Program EIS/EIR Study Area is served by I-10, SR 60, and SR 

111. Within the Coachella Valley, the main roadways that carry vehicles to the San Gorgonio Pass 

are I-10 and SR 111. The I-10 runs along the northeastern rim of the Coachella Valley while 

SR 111 runs approximately 30 miles along the southwestern rim of the Coachella Valley and serves 

as the main arterial highway between almost all Coachella Valley cities. 

5.2 Existing Noise Levels

Existing noise levels are calculated using methods in the FTA Manual, based on the existing 

frequency of train events. Day/night noise levels from total daily train operations were calculated for 

wayside and horn noise, based on the existing operations depicted in Table 5-1. Calculated ambient 

noise levels from existing train operation are depicted in Table 5-2.

In addition to rail operational noise, traffic noise from cars and trucks is a primary source of ambient 

noise within the Program Corridor. Many highways and local roads serve commuter and heavy 

trucking demands in both the Western and Eastern Section of the Program Corridor, including I-10, 

SR 60, and SR 91 in the Western Section and I-10, SR 60, and SR 111 in the Eastern Section.
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Table 5-2. Ambient Noise Levels within Program Corridor from Existing Train Operations

Section Train Noise Source

Ranges of Distance 

from Track (feet)

Range of Total Average 

Daily Ldn (dBA)

Range of Average Leq

(1 hour) (dBA)

Western Section

Los Angeles (Union 

Station-Sotoa)

Wayside noise from train passbys 50 – 150 63.4 – 70.5 58.4 –65.5

Los Angeles (Union 

Station-Sotoa)

Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 68.7 – 81.0 69.8 – 77.0

Los Angeles (Sotoa-Fullerton) Wayside noise from train passbys 50 - 150 70.6 – 77.8 64.6 –71.8

Los Angeles (Sotoa-Fullerton) Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 74.1 – 83.4 71.4 – 78.6

Fullerton-Atwood Wayside noise from train passbys 50 – 150 70.2 – 77.4 63.8 – 71.0

Fullerton‐Atwood Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 73.1 – 81.3 67.8 – 75.0

Atwood-Riverside Wayside noise from train passbys 50 – 150 70.7 – 77.8 64.3 – 71.5

Atwood-Riverside Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 73.8 – 82.4 69.6 – 76.8

Riverside‐Highgrove Wayside noise from train passbys 50 – 150 72.4 – 79.6 66.2 – 73.3

Riverside‐Highgrove Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 75.4 – 83.5 70.5 – 77.6

Highgrove‐Colton Wayside noise from train passbys 50 – 150 72.4 – 79.5 66.0 – 73.2

Highgrove‐Colton Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 75.3 – 82.9 69.6 – 76.8
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Section Train Noise Source

Ranges of Distance 

from Track (feet)

Range of Total Average 

Daily Ldn (dBA)

Range of Average Leq

(1 hour) (dBA)

Eastern Section

Colton-Coachella Wayside noise from train passbys 50 – 150 71.0 – 78.2 64.8 – 71.9

Colton-Coachella Horn noise levels within 0.25 mile of grade 

crossings

50 – 150 73.9 – 81.1 67.6 – 74.8

Notes:

a Soto interlocking (Milepost 144.4) in Los Angeles 

dBA=A-weighted decibel; Ldn=day-night average noise level; Leq=hourly equivalent A-weighted noise level
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5.3 Existing Vibration Levels

Existing vibration sources in the Tier 1/Program EIS/EIR Study Area include train traffic in the 

Western and Eastern Sections of the existing Program Corridor and motor vehicle traffic on freeways 

and local arterial streets. Existing vibration levels were not quantified in this evaluation, because FTA 

classification of vibration events would not change under future conditions with implementation of 

any of the Build Alternative Options. The Program would add two daily round-trips to existing train 

traffic; however, this increase would not be to a level that would result in a change in the overall FTA 

category from a vibration perspective. For the purposes of this evaluation, existing vibration levels 

are considered the same under Build Alternative Options 1, 2, and 3. 
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6 Environmental Consequences

6.1 Overview

Effects as a result of implementing the Build Alternative Options can be broadly classified into 

construction and operational effects. Both short-term or temporary effects and long-term or 

permanent noise and vibration effects would be anticipated as a result of constructing any of the 

Build Alternative Options. 

Construction effects associated with noise and vibration are generally short term and are due to the 

use of construction equipment and vehicles, as well as operation of on-site materials processing and 

handling, such as concrete plants. The potential construction effects on noise and vibration are 

evaluated based on the intensity and duration of the construction activities. The longer the 

construction period and the more non-road construction equipment used (such as cranes, 

bulldozers, heavy duty trucks, and concrete batch plants), the greater the potential for construction 

noise and vibration effects.

Noise and vibration effects could also result from operation of any of the Build Alternative Options as 

the addition of two daily roundtrips would result in the increase of passenger rail trains traveling 

within the Program Corridor and the addition of new station facilities (e.g., new sources of mobile 

and stationary noise). 

For both operation and construction, Build Alternative Option 1 is anticipated to result in the greatest 

noise and vibration impact due to a longer route alignment (i.e., addition of Indio to Coachella 

segment) and additional station option (Coachella Station option). When compared with Build 

Alternative Option 1, Build Alternative Option 2 may have slightly reduced effects due to a slightly 

smaller footprint associated with a shorter route alignment and fewer station options. When 

compared with Build Alternative Options 1 or 2, Build Alternative Option 3 may have slightly reduced 

effects due to a smaller footprint associated with a shorter route alignment, fewer station options, 

and reduced third track rail infrastructure. The magnitude of effects for all three Build Alternative 

Options would be similar when compared with the No Build Alternative, and, potential noise and 

vibration impacts as a result of the Program are conservatively evaluated largely in the context of the 

most intense alternative: Build Alternative Option 1. Site-specific sensitive land uses potentially 

affected by the Program would be further identified as part of the Tier 2/Project-level environmental 

review process. Specific types and degrees of noise and vibration impacts on sensitive receptors 

would not be known until further design and construction information is known.
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6.2 No Build Alternative

Under the No Build Alternative, there would be no Program-related construction or increase in 

service. Ambient noise and vibration levels from existing train operations and local traffic would 

continue.

The No Build Alternative assumes completion of those reasonably foreseeable transportation, 

development, and infrastructure projects that are already in progress, are programmed, or are 

included in the fiscally constrained regional transportation plan, including several existing and 

committed transportation improvement projects in the Western Section. These projects would result 

in an increase in freight service, as well as an increase in passenger rail services in the Western 

Section, which may increase noise and vibration levels; however, the expected increase in rail 

service would occur within the existing rail ROW.

An increase in traffic and vehicle miles traveled is expected with the No Build Alternative because 

more cars would be on the roadways compared with what would occur with implementation of the 

Program. Therefore, traffic congestion is likely to worsen with the No Build Alternative. An increase 

in rail service and an increase in cars on the roadways would not result in new impacts because 

ambient noise and vibration levels from existing train operations and local traffic would continue.

6.3 Build Alternative Options 1, 2, and 3

6.3.1 Western Section

Construction

The Build Alternative Options would not require construction of additional rail or station infrastructure 

in the Western Section of the Program Corridor because the existing railroad and stations from 

LAUS to Colton would be used. When compared with the No Build Alternative, short-term/temporary 

effects associated with noise-level increases would be negligible because no additional construction 

activities are planned within the Western Section of the Program Corridor under Build Alternative 

Options 1, 2, and 3.

Operation

Current (2018) daily rail traffic volumes on the Western Section (as shown in Table 5-1) vary by 

segment. The highest density segment is between Los Angeles and Fullerton and has an average of 

86 daily trains, while the lowest density segment is between Fullerton and Atwood and has an 

average of 43 daily trains. An additional two daily round-trip intercity passenger trains, even when 
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compared with the lowest density segment, would represent a 9-percent increase in train activity 

compared with current (2018) traffic volume along the existing railroad ROW. In 2024 and 2044, the 

Build Alternative Options would add the same number of rail operations to higher baseline 

conditions. Therefore, the Program’s effects in 2024 (6-percent increase) (RCTC and FRA 2021) 

and 2044 (3-percent increase) would be lower than those evaluated under existing conditions for the 

lowest density segment. The following evaluation considers the current (2018) traffic volumes. 

Rail Noise

A noise analysis was conducted using FTA methodologies to calculate existing and projected noise 

levels in the Western Section of the Program Corridor under Build Alternative Options 1, 2, and 3. 

Industrial, commercial, and noise-sensitive residential receptors are adjacent to the Build Alternative 

Options’ route alternatives throughout the Program Corridor; therefore, noise levels were computed 

at distances of 50, 100, and 150 feet from the Build Alternative Options’ route alignments to be 

representative of the high-end range of rail noise levels.

Table 6-1 details the assumed equipment consist for intercity passenger rail service under all of the 

Build Alternative Options. This consist would use equipment identical to the state-supported Pacific 

Surfliner trains currently providing state-supported intercity passenger service on regional routes 

serving LAUS.

Table 6-1. Coachella Valley – San Gorgonio Pass Corridor Service Intercity Passenger 

Train Consist

Equipment Type Units per Trainset

P42 diesel locomotive+ 1

Pacific Surfliner Business Class (77 revenue seats) 1

Pacific Surfliner Coach Café (72 revenue seats) 1

Pacific Surfliner Coach (90 revenue seats) 1

Pacific Surfliner Cab Coach Baggage Car (82 revenue seats) 1

Revenue Seating Capacity of Trainset 321

Patrons/crew on Board 200*

Maximum Authorized Speed 79 mph

Train Weight 360 tons

Train Horsepower per Ton 10.69
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Equipment Type Units per Trainset

Train Length 410 feet

Train Length (without locomotive) 340 feet

Notes:

+ FRA selected a P42 passenger locomotive as the preferred motive power for the Coachella Valley project’s 

operations simulation modeling of the proposed intercity passenger service, owing to a lack of real-world performance 

data for the Siemens Charger locomotive, which precluded the development of a Charger locomotive model for the 

Rail Traffic Controller operations simulation software. 

* Patrons/crew on board projection based on 2044 ridership forecast presented in the Program’s Alternatives Analysis 

report.

FRA=Federal Railroad Administration

Table 6-2 summarizes a conceptual train schedule for the proposed new intercity passenger service 

under Build Alternative Option 1, 2, and 3. The Build Alternative Options would result in the addition 

of four daytime (7:00 a.m. to 10:00 p.m.) one-way intercity train trips per day along the Western 

Section between Los Angeles and Colton.

Table 6-2. Proposed Coachella Valley – San Gorgonio Pass Rail Corridor Service 

Conceptual Train Schedule (Build Alternative Options 1, 2, and 3)

Eastbound: Read Down Miles Stations Miles Westbound: Read Up

Los Angeles – Indio: Build Alternative Option 1, 2, and 3

750 752 — Train No. — 751 753

10:20 AM 3:20 PM 0 Los Angeles 144 12:40 PM 6:40 PM

10:28 AM 3:28 PM 5 Soto (no stop) 139 12:26 PM 6:26 PM

10:55 AM 3:55 PM 26 Fullerton 118 12:06 PM 6:06 PM

11:39 AM 4:39 PM 62 Riverside 82 11:22 AM 5:22 PM

11:47 AM 4:47 PM 68 Colton (no stop) 76 11:12 AM 5:12 PM

11:59 AM 4:59 PM 72 Loma Linda 72 10:59 AM 4:59 PM

12:38 PM 5:38PM 103 Pass Area 41 10:20 AM 4:20 PM

1:02 PM 6:02 PM 118 Palm Springs 26 9:59 AM 3:59 PM

1:14 PM 6:14 PM 128 Mid Valley 16 9:45 AM 3:45 PM

1:30 PM 6:30 PM 141 Indio 3 9:32 AM 3:32 PM

Indio to Coachella – Build Alternative Option 1 only

1:38 PM 6:38 PM 144 Coachella 0 9:25 AM 3:25 PM
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Current average daily rail volumes in the Program Corridor range from 43 to 86 trains, consisting of 

freight, passenger, and commuter trains. The addition of four daily intercity trips would result in a 

cumulative total of up to 90 one-way trips per day on the Los Angeles-Fullerton segment, which 

carries the highest volume of trains. Loudest conditions occur on the Riverside-Highgrove segment, 

where a higher volume of daily freight trains contributes to ambient noise levels in this area. A 

summary of train volumes under existing and with-Program conditions is shown in Table 6-3. 

Table 6-3. Summary of Train Volumes under Existing (2018) and with-Program Conditions

(Build Alternative Options 1, 2, and 3)

Endpoints

Existing 

Freight 

One-way 

Train Trips 

(both 

directions)

Existing 

Passenger 

One-way 

Train Trips 

(both 

directions)

Total Existing 

Daily Volume 

of Trains (both 

directions)

Program 

Passenger 

One-way 

Train Trips 

(both 

directions)

Total 

With-Program

Daily Volume 

of Trains 

(both 

directions)

Western Section (Metrolink – Host Railroad; Additional Operators – Amtrak, BNSF)

Los Angeles Union 

Station-Soto*

1 54 55 4 59

Western Section (BNSF– Host Railroad; Additional Operators – Amtrak, Metrolink, Union 

Pacific)

Los Angeles (Soto*) –

Fullerton

32 54 86 4 90

Fullerton-Atwood 32 11 43 4 47

Atwood-Riverside 34 27 61 4 65

Riverside-Highgrove 54 22 76 4 80

Highgrove-Colton 54 10 64 4 68

Eastern Section (Union Pacific– Host Railroad; Additional Operator – Amtrak)

Colton-Coachella 42 1 43 4 47

Notes: 

Daily train counts represent revenue train movements on a weekday (Monday-Friday). Freight train counts are based 

on Base Year (2013) daily freight train totals for the line segments shown above, as published in the 2018 California 

State Rail Plan, Appendix A.4, Table 20. Passenger and commuter train counts are based on the following public 

timetables in effect in September 2018: Metrolink “All Lines” timetable effective May 14, 2018, the 2018 LOSSAN 

Southern California Passenger Rail System Map and Timetables effective April 1, 2018, the Amtrak Southwest Chief 

timetable effective July 31, 2018, and the Amtrak Sunset Limited timetable effective March 11, 2018. 

* Soto interlocking (Milepost 144.4) in Los Angeles
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Noise level calculations for train operations are depicted in Table 6-4 and Table 6-5. These trains 

would serve the Western Section of the Program Corridor from LAUS to the City of Colton. The 

results of the analysis are separated by wayside (engine and wheel/rail noise) and warning horn 

noise (at the at-grade grade crossings). Noise levels are shown in terms of Ldn for Category 2 uses 

and Leq for Category 3 uses, consistent with FTA methodology described in Section 3.1.3. As 

depicted in Table 6-4, no impacts are predicted to occur at Category 2 (residential/lodging) land uses 

at 50 feet from grade crossings. No impacts are predicted to occur at Category 3 (institutional) uses, 

as depicted in Table 6-5.
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Table 6-4. Western Section Noise Levels from Existing-plus-Program Train Operations, Category 2 (Residential) Land Uses

Endpoints

Train Noise 

Source

Distance 

from 

Track 

(feet)

Existing 

Average 

Daily Ldn 

(dBA)

Program

Ldn 

(dBA)

Combined 

Ldn (dBA)

Increase 

over 

Existing, 

dB

Moderate 

Impact 

Threshold

(Program Ldn)a

Severe 

Impact 

Threshold 

(Program 

Ldn)a Impact?

LAUS-Soto* Wayside 

noiseb

50 70.5 50.7 70.5 0.0 66 Ldn 70 Ldn None

LAUS-Soto* Wayside 

noiseb

100 66.0 46.2 66.0 0.0 62 Ldn 67 Ldn None

LAUS-Soto* Wayside 

noiseb

150 63.4 43.6 63.4 0.0 60 Ldn 65 Ldn None

LAUS-Soto* Horn noisec 50 81.0 64.6 81.1 + 0.1 66 Ldn 75 Ldn None

LAUS-Soto* Horn noisec 100 71.3 60.1 71.6 + 0.3 66 Ldn 70 Ldn None

LAUS-Soto* Horn noisec 150 68.7 57.5 69.0 + 0.3 64 Ldn 69 Ldn None

Los Angeles

(Soto*)-Fullerton

Wayside 

noiseb

50 77.8 50.7 77.8 0.0 66 Ldn 75 Ldn None

Los Angeles 

(Soto*)-Fullerton

Wayside 

noiseb

100 73.2 46.2 73.2 0.0 66 Ldn 71 Ldn None

Los Angeles 

(Soto*)-Fullerton

Wayside 

noiseb

150 70.6 43.6 70.6 0.0 66 Ldn 70 Ldn None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 50 83.4 64.6 83.5 + 0.1 66 Ldn 75 Ldn None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 100 76.7 60.1 76.8 + 0.1 66 Ldn 74 Ldn None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 150 74.1 57.5 74.2 + 0.1 66 Ldn 72 Ldn None

Fullerton‐Atwood Wayside 

noiseb

50 77.4 50.7 77.4 0.0 66 Ldn 74 Ldn None
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Endpoints

Train Noise 

Source

Distance 

from 

Track 

(feet)

Existing 

Average 

Daily Ldn 

(dBA)

Program

Ldn 

(dBA)

Combined 

Ldn (dBA)

Increase 

over 

Existing, 

dB

Moderate 

Impact 

Threshold

(Program Ldn)a

Severe 

Impact 

Threshold 

(Program 

Ldn)a Impact?

Fullerton‐Atwood Wayside 

noiseb

100 72.9 46.2 72.9 0.0 66 Ldn 71 Ldn None

Fullerton‐Atwood Wayside 

noiseb

150 70.2 43.6 70.2 0.0 65 Ldn 69 Ldn None

Fullerton‐Atwood Horn noisec 50 81.3 64.6 81.4 + 0.1 66 Ldn 75 Ldn None

Fullerton‐Atwood Horn noisec 100 75.8 60.1 75.9 + 0.1 66 Ldn 74 Ldn None

Fullerton‐Atwood Horn noisec 150 73.1 57.5 73.2 + 0.1 66 Ldn 71 Ldn None

Atwood-Riverside Wayside 

noiseb

50 77.8 50.7 77.8 0.0 66 Ldn 75 Ldn None

Atwood-Riverside Wayside 

noiseb

100 73.3 46.2 73.3 0.0 66 Ldn 71 Ldn None

Atwood-Riverside Wayside 

noiseb

150 70.7 43.6 70.7 0.0 66 Ldn 70 Ldn None

Atwood-Riverside Horn noisec 50 82.4 64.6 82.5 + 0.1 66 Ldn 75 Ldn None

Atwood-Riverside Horn noisec 100 76.4 60.1 76.5 + 0.1 66 Ldn 74 Ldn None

Atwood-Riverside Horn noisec 150 73.8 57.5 73.9 + 0.1 66 Ldn 72 Ldn None

Riverside‐

Highgrove

Wayside 

noiseb

50 79.6 50.7 79.6 0.0 66 Ldn 75 Ldn None

Riverside‐

Highgrove

Wayside 

noiseb

100 75.1 46.2 75.1 0.0 66 Ldn 73 Ldn None

Riverside‐

Highgrove

Wayside 

noiseb

150 72.4 43.6 72.4 0.0 66 Ldn 71 Ldn None

Riverside‐

Highgrove

Horn noisec 50 83.5 64.6 83.6 + 0.1 66 Ldn 75 Ldn None
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Endpoints

Train Noise 

Source

Distance 

from 

Track 

(feet)

Existing 

Average 

Daily Ldn 

(dBA)

Program

Ldn 

(dBA)

Combined 

Ldn (dBA)

Increase 

over 

Existing, 

dB

Moderate 

Impact 

Threshold

(Program Ldn)a

Severe 

Impact 

Threshold 

(Program 

Ldn)a Impact?

Riverside‐

Highgrove

Horn noisec 100 78.1 60.1 78.2 + 0.1 66 Ldn 75 Ldn None

Riverside‐

Highgrove

Horn noisec 150 75.4 57.5 75.5 + 0.1 66 Ldn 73 Ldn None

Highgrove‐Colton Wayside 

noiseb

50 79.5 50.7 79.5 0.0 66 Ldn 75 Ldn None

Highgrove‐Colton Wayside 

noiseb

100 75.0 46.2 75.0 0.0 66 Ldn 73 Ldn None

Highgrove‐Colton Wayside 

noiseb

150 72.4 43.6 72.4 0.0 66 Ldn 71 Ldn None

Highgrove‐Colton Horn noisec 50 82.9 64.6 83.0 + 0.1 66 Ldn 75 Ldn None

Highgrove‐Colton Horn noisec 100 77.9 60.1 78.0 + 0.1 66 Ldn 75 Ldn None

Highgrove‐Colton Horn noisec 150 75.3 57.5 75.4 + 0.1 66 Ldn 73 Ldn None

Notes:

a Moderate and severe impacts are compared with the Program’s contribution to existing levels (i.e., the Program Ldn). These thresholds do not apply to the 

combined Ldn.

b Wayside noise from train passbys

c Horn noise levels within 0.25 mile of grade crossings

LAUS=Los Angeles Union Station; Ldn=Day-night average noise level; Leq=Hourly equivalent A-weighted noise level; dBA=A-weighted decibel
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Table 6-5. Western Section Noise Levels from Existing-plus-Program Train Operations, Category 3 (Institutional) Land Uses

within the Tier 1/Program EIS/EIR Study Area

Endpoints

Train Noise 

Source

Distance 

from Track 

(feet)

Existing 

Average 

Daily Leq 

(dBA)

Program 

Leq (dBA)

Combined 

Leq (dBA)

Increase

over

Existing

Moderate 

Impact 

Threshold

(Program

Leq)a

Severe 

Impact 

Threshold 

(Program 

Leq)

a Impact?

LAUS-Soto* Wayside 

noiseb

50 65.5 52.8 65.7 + 0.2 67 Leq 72 Leq None

LAUS-Soto* Wayside 

noiseb

100 61.0 48.3 61.2 + 0.2 64 Leq 69 Leq None

LAUS-Soto* Wayside 

noiseb

150 58.4 45.6 58.6 + 0.2 62 Leq 67 Leq None

LAUS-Soto* Horn noisec 50 77.0 66.7 77.4 + 0.4 71 Leq 79 Leq None

LAUS-Soto* Horn noisec 100 72.5 62.2 72.9 + 0.4 71 Leq 76 Leq None

LAUS-Soto* Horn noisec 150 69.8 59.5 70.2 + 0.4 70 Leq 74 Leq None

Los Angeles

(Soto*)-Fullerton

Wayside 

noiseb

50 71.8 52.8 71.9 + 0.1 71 Leq 76 Leq None

Los Angeles 

(Soto*)-Fullerton

Wayside 

noiseb

100 67.2 48.3 67.3 + 0.1 68 Leq 72 Leq None

Los Angeles 

(Soto*)-Fullerton

Wayside 

noiseb

150 64.6 45.6 64.7 + 0.1 66 Leq 71 Leq None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 50 78.6 66.7 78.9 + 0.3 71 Leq 80 Leq None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 100 74.1 62.2 74.4 + 0.3 71 Leq 77 Leq None

Los Angeles 

(Soto*)-Fullerton

Horn noisec 150 71.4 59.5 71.7 + 0.3 71 Leq 75 Leq None
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Endpoints

Train Noise 

Source

Distance 

from Track 

(feet)

Existing 

Average 

Daily Leq 

(dBA)

Program 

Leq (dBA)

Combined 

Leq (dBA)

Increase

over

Existing

Moderate 

Impact 

Threshold

(Program

Leq)a

Severe 

Impact 

Threshold 

(Program 

Leq)

a Impact?

Fullerton‐Atwood Wayside 

noiseb

50 71.0 52.8 71.1 + 0.1 71 Leq 75 Leq None

Fullerton‐Atwood Wayside 

noiseb

100 66.5 48.3 66.6 + 0.1 68 Leq 72 Leq None

Fullerton‐Atwood Wayside 

noiseb

150 63.8 45.6 63.9 + 0.1 66 Leq 70 Leq None

Fullerton‐Atwood Horn noisec 50 75.0 66.7 75.6 + 0.6 71 Leq 78 Leq None

Fullerton‐Atwood Horn noisec 100 70.5 62.2 71.1 + 0.6 71 Leq 75 Leq None

Fullerton‐Atwood Horn noisec 150 67.8 59.5 68.4 + 0.6 68 Leq 73 Leq None

Atwood-Riverside Wayside 

noiseb

50 71.5 52.8 71.6 + 0.1 71 Leq 76 Leq None

Atwood-Riverside Wayside 

noiseb

100 67.0 48.3 67.1 + 0.1 68 Leq 72 Leq None

Atwood-Riverside Wayside 

noiseb

150 64.3 45.6 64.4 + 0.1 66 Leq 70 Leq None

Atwood-Riverside Horn noisec 50 76.8 66.7 77.2 + 0.4 71 Leq 79 Leq None

Atwood-Riverside Horn noisec 100 72.3 62.2 72.7 + 0.4 71 Leq 76 Leq None

Atwood-Riverside Horn noisec 150 69.6 59.5 70.0 + 0.4 70 Leq 74 Leq None

Riverside‐

Highgrove

Wayside 

noiseb

50 73.3 52.8 73.3 0.0 71 Leq 76 Leq None

Riverside‐

Highgrove

Wayside 

noiseb

100 68.8 48.3 68.8 0.0 69 Leq 74 Leq None

Riverside‐

Highgrove

Wayside 

noiseb

150 66.2 45.6 66.2 0.0 67 Leq 72 Leq None
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Endpoints

Train Noise 

Source

Distance 

from Track 

(feet)

Existing 

Average 

Daily Leq 

(dBA)

Program 

Leq (dBA)

Combined 

Leq (dBA)

Increase

over

Existing

Moderate 

Impact 

Threshold

(Program

Leq)a

Severe 

Impact 

Threshold 

(Program 

Leq)

a Impact?

Riverside‐

Highgrove

Horn noisec 50 77.6 66.7 77.9 + 0.3 71 Leq 80 Leq None

Riverside‐

Highgrove

Horn noisec 100 73.1 62.2 73.4 + 0.3 71 Leq 76 Leq None

Riverside‐

Highgrove

Horn noisec 150 70.5 59.5 70.8 + 0.3 71 Leq 75 Leq None

Highgrove‐Colton Wayside 

noiseb

50 73.2 52.8 73.2 0.0 71 Leq 76 Leq None

Highgrove‐Colton Wayside 

noiseb

100 68.7 48.3 68.7 0.0 69 Leq 74 Leq None

Highgrove‐Colton Wayside 

noiseb

150 66.0 45.6 66.0 0.0 67 Leq 72 Leq None

Highgrove‐Colton Horn noisec 50 76.8 66.7 77.2 + 0.4 71 Leq 79 Leq None

Highgrove‐Colton Horn noisec 100 72.3 62.2 72.7 + 0.4 71 Leq 76 Leq None

Highgrove‐Colton Horn noisec 150 69.6 59.5 70.0 + 0.4 70 Leq 74 Leq None

Notes:

a Moderate and severe impacts are compared with the Program’s contribution to existing levels (i.e., the Program Ldn). These thresholds do not apply to the 

combined Ldn.

b Wayside noise from train passbys

c Horn noise levels within 0.25 mile of grade crossings

LAUS=Los Angeles Union Station; Ldn=Day-night average noise level; Leq=Hourly equivalent A-weighted noise level; dBA=A-weighted decibel
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The cumulative increase in noise is the basis for the FTA noise impact criteria depicted on 

Figure 6-1 (FTA 2018). At a distance of 50 feet, the noise levels under each Build Alternative Option

would be below the moderate impact threshold for both wayside and horn noise.

Figure 6-1. Program Noise Exposure Relative to Existing Conditions

Source: FTA 2018.

Vibration

The number of average daily trips in the Western Section of the Program Corridor would increase 

from a maximum of 86 per day to 90 per day, which would not result in a change in classification 

from “frequent events” (e.g., more than 70 events per day) under FTA. Train speeds are not 

projected to increase under future conditions. 

Similar to the noise analysis, because the Build Alternative Options’ route alignments would not 

change relative to existing conditions, the evaluation focuses on the increase in commuter rail trips 

that would occur under the Build Alternative Options. As described in Section 3.1.3, the FTA 

classification of vibration events under existing conditions is “frequent events.” This classification 
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would not change with implementation of the Build Alternative Options. If train traffic with the 

implementation of the Build Alternative Options would exceed the vibration criteria for “frequent 

events” and increase vibration levels by 3 VdB or more, this would result in an impact. However, 

train activity with implementation of the Program would involve commuter vehicles, which produce 

vibration levels that are more than 10 dB below freight trains in terms of VdB root-mean-square 

values. Therefore, no operational vibration impacts are expected.

6.3.2 Eastern Section

Construction 

Noise

Specific infrastructure improvements may include sidings, additional main line track, wayside 

signals, drainage, grade-separation structures, and stations in the Eastern Section; however, 

specific improvements and locations have not yet been determined for the Tier 1/Program EIS/EIR 

evaluation. Potential worst-case equipment noise levels from construction of proposed infrastructure 

improvements were evaluated by combining the noise levels of up to three of the loudest pieces of 

equipment that would most likely operate at the same time during a given phase of construction. 

This worst-case analysis assumes a paving project, which would include a paver, a dump truck, and 

an excavator, with an overall noise level of 88 dBA Leq (8 hours) at 50 feet. Estimated overall noise 

levels, based on attenuation over hard (i.e., acoustically reflective) ground, as a function of distance,

are depicted in Table 6-6. 

Although equipment may operate in many different areas as the Program is constructed, the highest 

noise levels are expected at those sites where the duration and intensity of construction activities 

would be greatest. Construction may extend through several residential areas and communities 

adjacent to the Build Alternative Options’ route alignments in the Eastern Section of the Program 

Corridor. 

Table 6-6. Construction Equipment Noise Emission Levels by Distance

Distance Between Source and Receptor (feet) Calculated Leq Sound Level (dBA)

50 88

60 86

70 85

80 84

100 82
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Distance Between Source and Receptor (feet) Calculated Leq Sound Level (dBA)

120 80

150 78

200 76

250 74

300 72

350 71

400 70

500 68

1,000 62

Notes:

Calculations based on FTA 2018; Thalheimer 2000.

This calculation does not include the effects, if any, of local shielding from walls, topography, or other barriers that may 

reduce sound levels further.

dBA=A-weighted decibel; Leq=Hourly equivalent A-weighted noise level

Noise from construction activities is predicted to exceed the FTA daytime construction noise criterion 

at nearby residences, lodging facilities, and institutional uses within 120 feet of construction areas. 

The FTA nighttime noise criterion would be exceeded at residences and lodging facilities at a 

distance of up to 400 feet from construction areas. The need for construction during nighttime hours 

has not been specified and is, therefore, assumed to occur as a worst-case evaluation.

Impact pile drivers produce a maximum noise level of up to 101 dBA at a distance of 50 feet. If 

impact pile driving is used, the FTA daytime criterion may be exceeded at a distance of up to 

275 feet, and the FTA nighttime criterion may be exceeded at a distance of up to 850 feet. The need

for pile driving during construction has not been specified and is, therefore, assumed to occur as a 

worst-case evaluation.

Construction at a given location for each phase of the Program would be intermittent and short term 

for the noise-sensitive receptors adjacent to construction sites. Noise related to construction of the 

Build Alternative Options would cease once the Program is complete.

Noise impacts during construction would potentially occur at receivers located within 275 feet of 

construction activity during daytime hours and within 850 feet of construction activity during nighttime 

hours. Site-specific noise impacts and mitigation measures would be considered during 

Tier 2/Project-level analysis. 
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Vibration

Construction of the Build Alternative Options would result in temporary vibration along the Eastern 

Section of the Program Corridor from the use of heavy equipment and machinery. The vibration 

levels from construction activities were estimated using the equipment data in Table 4-2. The results 

are summarized in Table 6-7.

Table 6-7. Construction Equipment Vibration Levels by Distance

Distance 

Between 

Source and 

Receptor (feet)

Pile Driver 

(VdB)

Pile Driver 

(PPV)

Vibratory 

Roller (VdB)

Vibratory 

Roller (PPV)

Bulldozer 

(VdB)

Bulldozer 

(PPV)

25 104 0.644 94 0.210 87 0.089

40 98 0.384 88 0.125 81 0.053

50 95 0.300 85 0.098 78 0.042

60 93 0.246 83 0.080 76 0.034

63 92 0.233 82 0.076 75 0.032

70 91 0.207 81 0.068 74 0.029

75 90 0.192 80 0.063 73 0.027

100 86 0.140 76 0.046 69 0.019

110 85 0.126 75 0.041 68 0.017

160 80 0.084 70 0.027 63 0.012

200 77 0.065 67 0.021 60 0.009

230 75 0.056 65 0.018 58 0.008

250 74 0.051 64 0.017 57 0.007

Notes:

Calculations based on FTA 2018.

VdB=vibration velocity decibels; PPV=peak particle velocity (inch per second)

Ground-borne vibration from construction activities may periodically exceed the FTA vibration 

criterion at residences and lodging facilities within 110 feet of construction areas when using typical 

heavy equipment. If impact equipment, such as a pile driver, is used, the FTA vibration criterion 

would be exceeded at up to 230 feet. As depicted in Table 6-7, vibration levels from operation of a 

vibratory roller would exceed the FTA vibration criterion of 75 VdB at a distance of 110 feet, while 

operation of a bulldozer would exceed the criterion at a distance of 63 feet. Vibration levels from a 

vibratory roller would exceed the criterion for building damage at a distance of 25 feet. Pile drivers 
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would exceed the building damage criterion at approximately 70 feet. Although vibration from 

construction equipment may be intermittently perceptible at sensitive receptor locations, the potential 

for substantial annoyance of occupants at nearby building structures is unlikely and would occur only 

during short intervals when equipment is operated near structures.

Vibration impacts during construction of the Build Alternative Options would potentially occur at 

receivers located within 230 feet of construction activity during daytime hours. Site-specific vibration 

impacts would be considered during Tier 2/Project-level analysis.

Operation 

Current (2018) daily rail traffic volumes on the Eastern Section (as shown in Table 5-1) average 

43 daily trains along the Colton-Coachella segment, consisting of freight and passenger trains. The 

addition of two daily round-trip intercity passenger trains would represent a 9-percent increase in 

train activity compared with current (2018) traffic volume along the existing railroad ROW. In 2024 

and 2044, the Program would add the same number of rail operations to higher baseline conditions. 

Therefore, the Program’s effects in 2024 (8-percent increase) (RCTC and FRA 2021) and 2044 

(4.5-percent increase) would be lower than those evaluated under existing conditions. The following 

evaluation considers the current (2018) traffic volumes.

Rail Noise

Noise calculations for train operations along the Eastern Section are depicted in Table 6-8 and 

Table 6-9. Because the Program Corridor would not change relative to existing conditions, the 

evaluation focuses on the increase in intercity passenger rail trips that would occur along the 

Program Corridor. Noise levels are reported in terms of distance from the track.

The Build Alternative Options would add four daytime (7:00 a.m. to 10:00 p.m.) one-way intercity 

train trips per day along the Eastern Section. These trains would serve the area between the cities of 

Colton and Indio and/or Coachella within San Bernardino and Riverside counties. 

Table 6-8 and Table 6-9 show the results of the evaluation, separated by wayside (engine and 

wheel/rail noise) and horn noise (at the at-grade grade crossings). As depicted in Table 6-8 no 

impacts are predicted to occur at Category 2 land uses 50 feet from grade crossings. No impacts are 

predicted to occur at institutional uses, as depicted in Table 6-9. 
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Table 6-8. Eastern Section Noise Levels from Existing-plus-Program Train Operations, Category 2 (Residential) Land Uses

(Colton-Coachella Section) within the Program Corridor

Train Noise 

Source

Distance 

from Track 

(feet)

Existing 

Average Daily 

Ldn (dBA)

Program

Ldn (dBA)

Combined 

Ldn (dBA)

Increase 

over 

Existing, 

dB

Moderate 

Impact 

Threshold

(Program Ldn)a

Severe Impact 

Threshold 

(Program Ldn)

a Impact?

Wayside noise 

from train passbys

50 78.4 50.7 78.4 0.0 66 Ldn 75 Ldn None

Wayside noise 

from train passbys

100 73.9 46.2 73.9 0.0 66 Ldn 72 Ldn None

Wayside noise 

from train passbys

150 71.3 43.6 71.3 0.0 66 Ldn 70 Ldn None

Horn noise levels 

within 0.25 mile of 

grade crossings

50 81.3 64.6 81.4 + 0.1 66 Ldn 75 Ldn None

Horn noise levels 

within 0.25 mile of 

grade crossings

100 76.8 60.1 76.9 + 0.1 66 Ldn 74 Ldn None

Horn noise levels 

within 0.25 mile of 

grade crossings

150 74.2 57.5 74.3 + 0.1 66 Ldn 72 Ldn None

Notes:

a Moderate and severe impacts are compared with the Program’s contribution to existing levels (i.e., the Programt Ldn). These thresholds do not apply to the 

combined Ldn.

Ldn=Day-night average noise level; Leq=Hourly equivalent A-weighted noise level; dBA=A-weighted decibel
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Table 6-9. Eastern Section Noise Levels from Existing-plus-Program Train Operations, Category 3 (Institutional) Land Uses

(Colton-Coachella Section) within the Program Corridor

Train Noise 

Source

Distance from 

Track (feet)

Existing 

Average 

Daily Leq 

(dBA)

Program Leq

(dBA)

Combined 

Leq (dBA)

Increase 

over 

Existing, 

dB

Moderate 

Impact 

Threshold

(Program

Leq)

a

Severe Impact 

Threshold 

(Program Leq)

a Impact?

Wayside noise 

from train 

passbys

50 72.0 52.8 72.1 + 0.1 71 Leq 76 Leq None

Wayside noise 

from train 

passbys

100 67.4 48.3 67.5 + 0.1 68 Leq 72 Leq None

Wayside noise 

from train 

passbys

150 64.8 45.6 64.9 + 0.1 66 Leq 71 Leq None

Horn noise levels 

within 0.25 mile 

of grade 

crossings

50 75.0 66.7 75.6 + 0.6 71 Leq 78 Leq None

Horn noise levels 

within 0.25 mile 

of grade 

crossings

100 70.5 62.2 71.1 + 0.6 71 Leq 75 Leq None

Horn noise levels 

within 0.25 mile 

of grade 

crossings

150 67.8 59.5 68.4 + 0.6 68 Leq 73 Leq None

Notes:

a Moderate and severe impacts are compared with the Program’s contribution to existing levels, (i.e., the Program Ldn). These thresholds do not apply to the 

combined Ldn.

Ldn=Day-night average noise level; Leq=Hourly equivalent A-weighted noise level; dBA=A-weighted decibel
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The cumulative increase in noise is the basis for the FTA noise impact criteria depicted on

Figure 6-1 (FTA 2018). At a distance of 50 feet, the noise level associated with operation of the Build 

Alternative Options would be below the moderate impact threshold for both wayside and horn noise.

Operation improvements may include grade-separation structures and stations in the Eastern 

Section; however, specific improvements and locations of stations and grade-separations have not 

yet been determined for the Tier 1/Program EIS/EIR evaluation.

In general, grade-separations would remove the requirement for trains to sound horns at crossings 

(as required for at-grade crossings), which would result in substantially lower noise levels near

crossings where a conversion to a grade-separated structure is implemented.

Station platform noise sources generally include a public announcement system and chiming sounds 

from ticket vending machines. Announcement systems are typically designed to adjust volume levels 

automatically to a few decibels above ambient noise. Operation noise associated with these sources 

would occur for brief periods and would not be likely to result in an exceedance of FTA or local 

standards. Tier 2/Project-level analyses would quantitatively analyze potential operational noise. 

Traffic Noise

New train ridership resulting from implementation of the Build Alternative Options is expected to 

affect the number of automobile trips east of Colton. The forecast for ridership in 2024 indicates a 

reduction in the number of automobile trips (between 263 to 358 per day), based on the number of 

train stops. This would result in a very small decrease in future traffic noise levels (less than 0.1 dB 

on a given road), which would not be a perceptible change relative to future No Build Alternative

conditions in the same year. 

Vibration

The number of one-way daily trips on the Eastern Section would increase from 43 per day to 47 per 

day, which would not result in a change in classification from “occasional events” (e.g., between 

30 and 70 events per day) under FTA. Train speeds are not projected to increase under future 

conditions. Potential changes to vibration levels associated with operation of the Build Alternative

Options in the Eastern Section would be similar to that described under the Western Section. 
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7 Tier 2 Environmental Review

Considerations

The Tier 1/Program EIS/EIR evaluation provides an overview of potential impacts resulting from 

development of the Build Alternative Options. Specific station locations, Tier 2/Project-level design, 

and construction methods have not been determined. 

Tier 2/Project-level analyses would calculate the existing and future levels of ambient noise and 

vibration and would identify locations of sensitive receptors that may potentially be affected by noise 

and/or vibration under Tier 2 projects. The Tier 1/Program EIS/EIR indicated noise impacts during 

construction would potentially occur at receivers within 275 feet of construction activity during 

daytime hours and within 850 feet of construction activity during nighttime hours. Operation noise 

levels from additional train trips, new stations, and grade separations are not anticipated to exceed 

FTA impact criteria. The Tier 2/Project-level analysis would include numbers of residences and types 

of land uses affected. The Tier 2/Project-level analysis would also include a quantitative evaluation 

of potential noise and vibration effects on wildlife and natural parks. 

Identified below are proposed programmatic mitigation strategies for further consideration in the Tier 

2/Project-level analysis. Specific mitigation measures, to the extent required, would be identified and 

discussed during Tier 2/Project-level analysis after design details are known and specific impacts 

are identified. Potential mitigation measures and design features that would avoid or minimize noise

and vibration effects would be developed in consultation with the appropriate agencies with 

jurisdiction. Proposed programmatic mitigation strategies include, but are not limited to the following:

• During Tier 2/Project-level analysis, a site-specific construction noise management plan shall 

be prepared for the specific rail infrastructure or station facility proposed. The construction 

noise management plan shall include, but not be limited to, the following:

o A detailed construction schedule correlating to areas or zones of on-site Project 

construction activity(ies) and the anticipated equipment types and quantities involved. 

Information will include expected hours of actual operation per day for each type of 

equipment per phase and indication of anticipated concurrent construction activities on 

site.

o Identification of construction noise reduction methods such as shutting off idling 

equipment, construction of a temporary noise barrier, maximizing the distance between 

construction equipment staging areas and adjacent sensitive land use receptors.
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o Identification of construction hours, allowable workdays, and the phone number of the job 

superintendent shall be clearly posted at all construction entrances to allow surrounding 

property owners to contact the job superintendent if necessary. In the event the 

municipality with jurisdiction receives a complaint, the construction noise management 

plan shall include guidance to ensure the appropriate corrective actions are implemented 

and a report of the action is provided to the reporting party. Appropriate corrective 

actions may include stricter enforcement of construction schedule, re-location of 

stationary equipment further from adjacent noise-sensitive receptors, reduction in the 

number of equipment working simultaneously in proximity to the sensitive receptor, 

erection of temporary noise barriers, or a combination of the above.

• During Tier 2/Project-level analysis, a site-specific noise and vibration assessment shall be 

prepared for the specific rail infrastructure or station facility proposed. The site-specific noise 

and vibration assessment shall include, but not be limited to, the following:

o Identification of adjacent noise sensitive land uses that would be impacted by 

construction and operation activities associated with the specific rail infrastructure or 

station facility. 

o Identification of construction equipment required to be within 50 feet of existing 

structures. If construction equipment is required within 50 feet, the assessment will 

demonstrate that the human annoyance threshold of 78 VdB (0.032 inches per second 

PPV) and structural damage thresholds of 0.2 inches per second PPV for 

non-engineered timber and masonry buildings and 0.12 inches per second PPV for 

historic-age buildings that are extremely susceptible to vibration damage is achieved.

o Identification of existing noise levels at the nearest noise sensitive land uses. 

o Identification of any on-site generated noise sources, including generators, mechanical 

equipment, and trucks and predicted noise levels at property lines from all identified 

equipment.

o Recommended mitigation to be implemented (e.g., enclosures, barriers, site orientation), 

to ensure compliance with the local jurisdiction’s noise regulations or ordinances. Noise 

reduction measures shall include building noise-attenuating walls, reducing noise at the 

source by requiring quieter machinery or limiting the hours of operation, or other 

attenuation measures. Exact noise mitigation measures and their effectiveness shall be 

determined by the site-specific noise analyses.
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8 References

California Department of Transportation (Caltrans). 2004. Transportation- and Construction-Induced 

Vibration Guidance Manual. Noise, Vibration, and Hazardous Waste Management Office. 

June. Sacramento, CA. J and S 02-039. Prepared by Jones and Stokes, Sacramento, CA. 

——— 2009. Technical Noise Supplement, pp. 2-48 and 2-49. Division of Environmental Analysis. 

November. http://www.dot.ca.gov/hq/env/noise/pub/tens_complete.pdf. 

California Office of Noise Control. 1977. Model Community Noise Ordinance. April. Berkeley, CA: 

California Department of Health.

Federal Railroad Administration (FRA). 1999. Procedures for Considering Environmental Impacts. 

Section 14(n)(3). Accessed July 24, 2018. 

https://www.transportation.gov/sites/dot.gov/files/docs/FRAEnvProcedures_FED_REG_Notic

e.pdf. 

——— 2012. High-Speed Ground Transportation Noise and Vibration Impact Assessment. 

(DOT/FRA/ORD-12/15.) Washington, DC: Office of Railroad Policy and Development.

Federal Transit Administration (FTA). 2018. Transit Noise and Vibration Impact Assessment Manual. 

(FTA Report No. 0123.) Washington, DC: Office of Planning and Environment. September.

Riverside County Transportation Commission (RCTC) and Federal Railroad Administration (FRA). 

2021. Coachella Valley-San Gorgonio Pass Rail Corridor Service Project Environmental 

Impact Statement/Environmental Impact Report (Draft). Prepared by HDR Engineering, Inc. 

Governor’s Office of Planning and Research. 2003. Guidelines for the Preparation and Content of 

the Noise Element of the General Plan. Appendix C in the State of California General Plan 

Guidelines. Sacramento, CA.

Thalheimer, E. 2000. Construction Noise Control Program and Mitigation Strategy at the Central 

Artery/Tunnel Project. Noise Control Engineering Journal. 48(5):157–165. 

United States Environmental Protection Agency (U.S. EPA). 1974. Information on Levels of 

Environmental Noise Requisite to Protect Public Health and Welfare with an Adequate 

Margin of Safety. March. Washington, DC: United States Environmental Protection Agency, 

Office of Noise Abatement and Control.
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Appendix A. Fundamental Concepts of 

Environmental Noise
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Fundamental Concepts of Environmental Noise

Sound, Noise, and Acoustics

Sound can be described as the mechanical energy of a vibrating object transmitted by pressure waves 

through a liquid or gaseous medium (e.g., air) to a hearing organ, such as a human ear. Noise is 

defined as loud, unexpected, or annoying sound.

In the science of acoustics, the fundamental model consists of a sound (or noise) source, a receiver, 

and the propagation path between the two. The loudness of the noise source and the obstructions or 

atmospheric factors that affect the propagation path to the receiver determine the sound level and 

characteristics of the noise perceived by the receiver. The field of acoustics deals primarily with the 

propagation and control of sound.

Frequency

Continuous sound can be described by frequency (pitch) and amplitude (loudness). A low-frequency 

sound is perceived as low in pitch. Frequency is expressed in terms of cycles per second, or Hertz 

(Hz) (e.g., a frequency of 250 cycles per second is referred to as 250 Hz). High frequencies are 

sometimes more conveniently expressed in kilohertz (kHz), or thousands of Hz. The audible frequency 

range for humans is generally between 20 and 20,000 Hz.

Sound Pressure Levels and Decibels

The amplitude of pressure waves generated by a sound source determines the loudness of that 

source. Sound pressure amplitude is measured in micropascals (mPa). One mPa is approximately 

one-hundred billionth (0.00000000001) of normal atmospheric pressure. Sound pressure amplitudes 

for different kinds of noise environments can range from less than 100 to 100,000,000 mPa. Because 

of this huge range of values, sound is rarely expressed in terms of mPa. Instead, a logarithmic scale 

is used to describe the sound pressure level (SPL) in terms of decibels (dB). The threshold of hearing 

for young people is about 0 dB, which corresponds to 20 mPa.

Addition of Decibels

Because dBs are logarithmic units, SPL cannot be added or subtracted through ordinary arithmetic. 

Under the dB scale, a doubling of sound energy corresponds to a 3 dB increase. In other words, when 

two identical sources are each producing sound of the same loudness, the resulting sound level at a 

given distance would be 3 dB higher than one source under the same conditions. For example, if one 

automobile produces an SPL of 70 dB when it passes an observer, two cars passing simultaneously 

would not produce 140 dB—rather, they would combine to produce 73 dB. Under the dB scale, three 

sources of equal loudness together produce a sound level 5 dB louder than one source.

A-Weighted Decibels

The dB scale alone does not adequately characterize how humans perceive sound. The dominant 

frequencies of a sound have a substantial effect on human response to that sound. Although the 

intensity (energy per unit area) of the sound is a purely physical quantity, the loudness or human 

response is determined by the characteristics of the human ear.

Human hearing is limited in its range of audible frequencies as well as the way in which it perceives 

the SPL in that range. In general, people are most sensitive to the frequency range of 1,000 to 8,000 
Hz and perceive sounds within that range better than sounds of the same amplitude in higher or lower 

frequencies. To approximate the response of the human ear, sound levels of individual frequency 

bands are weighted, depending on human sensitivity to those frequencies. Then, an “A weighted” 

sound level (expressed in units of dBA) can be computed, based on this information.

The A-weighting network approximates the frequency response of the average young ear when 

listening to most ordinary sounds. When people judge the relative loudness or annoyance of a sound, 

their judgments correlate well with A-weighted sound levels of those sounds. Other weighting networks 

(e.g., B, C, and D scales) have been devised to address high noise levels or other special problems, 

but these scales are rarely used in conjunction with transit- or highway-related noise. Noise levels for 

technical reports related to transit or traffic noise are typically reported in terms of A-weighted decibels, 

or dBA. Table A-1 describes typical A-weighted noise levels for various noise sources.

Table A-1. Typical A-Weighted Noise Levels

Common Outdoor Activities or 

Conditions

Noise Level 

(dBA) Common Indoor Activities or Locations

— 110 — Rock band

Jet flying at 1,000 feet

— 100 —

Gas lawn mower at 3 feet

— 90 —

Diesel truck at 50 feet at 50 mph Food blender at 3 feet

— 80 — Garbage disposal at 3 feet

Noisy urban area, daytime

Gas lawn mower, 100 feet — 70 — Vacuum cleaner at 10 feet

Commercial area Normal speech at 3 feet

Heavy traffic at 300 feet — 60 —

Large business office

Quiet urban daytime — 50 — Dishwasher next room

Quiet urban nighttime — 40 — Theater, large conference room (background)

Quiet suburban nighttime

— 30 — Library

Quiet rural nighttime Bedroom at night, concert

— 20 —

Broadcast/recording studio

— 10 —

Lowest threshold of human hearing — 0 — Lowest threshold of human hearing

Source: California Department of Transportation, 2009.
Human Response to Changes in Noise Levels

As discussed above, a doubling of sound energy results in a 3 dB increase in sound. However, when 

the sound level change is measured with precise instrumentation, the subjective human perception of 

the doubling of loudness will usually be different from what is measured.

Under controlled conditions in an acoustical laboratory, the trained, healthy human ear is able to 

discern 1 dB changes in sound levels when exposed to steady, single-frequency (“pure-tone”) signals 

in the mid-frequency (1,000 to 8,000 Hz) range. In typical noisy environments, changes in noise of 1 

to 2 dB are generally not perceptible. However, it is widely accepted that people are able to begin to 

detect sound-level increases of 3 dB in typical noisy environments. Further, a 5 dB increase is 

generally perceived as a distinctly noticeable increase, and a 10 dB increase is generally perceived 

as a doubling of loudness. Therefore, a doubling of sound energy (e.g., doubling the volume of traffic 

on a highway) that would result in a 3 dB increase in sound would generally be perceived as barely 

detectable.

Noise Descriptors

Noise in our daily environment fluctuates over time. Various noise descriptors have been developed 

to describe time-varying noise levels. The following are the noise descriptors most commonly used in 

transit noise analysis.

 Equivalent Sound Level (Leq): Leq represents an average of the sound energy occurring over

a specified period. In effect, Leq is the steady-state sound level containing the same

acoustical energy as the time-varying sound that actually occurs during the same period. The

1-hour A weighted equivalent sound level, or Leq(h), is the energy average of A-weighted

sound levels occurring during a 1-hour period.

 Percentile-Exceeded Sound Level (Lxx): Lxx represents the sound level exceeded for a given

percentage of a specified period (e.g., L10 is the sound level exceeded 10 percent of the

time, and L90 is the sound level exceeded 90 percent of the time).

 Maximum Sound Level (Lmax): Lmax is the highest instantaneous sound level measured during

a specified period.

 Day/Night Level (Ldn): Ldn is the energy average of A-weighted sound levels occurring over a

24-hour period, with a 10 dB penalty applied to A-weighted sound levels occurring during

nighttime hours between 10 p.m. and 7 a.m.

 Community Noise Equivalent Level (CNEL): Similar to Ldn, CNEL is the energy average of

the A-weighted sound levels occurring over a 24-hour period, with a 10 dB penalty applied to

A weighted sound levels occurring during the nighttime hours between 10 p.m. and 7 a.m.

and a 5 dB penalty applied to the A-weighted sound levels occurring during evening hours

between 7 p.m. and 10 p.m.

Sound Propagation

When sound propagates over a distance, it changes in level and frequency content. The manner in 

which noise reduces with distance depends on the factors described below.

Geometric Spreading

Sound from a localized source (i.e., a point source) propagates uniformly outward in a spherical 

pattern. The sound level attenuates (or decreases) at a rate of 6 dB for each doubling of distance from 

a point source. Roadways consist of several localized noise sources on a defined path and, hence, 
can be treated as a line source, which approximates the effect of several point sources. Noise from a 

line source propagates outward in a cylindrical pattern, often referred to as cylindrical spreading. 

Sound levels attenuate at a rate of 3 dB for each doubling of distance from a line source. 

Ground Absorption

The propagation path of noise from a roadway to a receiver is usually very close to the ground. Noise 

attenuation from ground absorption and reflective wave canceling adds to the attenuation associated 

with geometric spreading. Traditionally, excess attenuation has been expressed in terms of 

attenuation per doubling of distance. This approximation is usually sufficiently accurate for distances 

of less than 200 feet. For acoustically hard sites (i.e., sites with a reflective surface between the source 

and the receiver, such as a parking lot or body of water), no excess ground attenuation is assumed. 

For acoustically absorptive or soft sites (i.e., sites with an absorptive ground surface, such as soft dirt, 

grass, or scattered bushes and trees between the source and the receiver), an excess groundattenuation value of 1.5 dB per doubling of distance is normally assumed. When added to the 

cylindrical spreading, the excess ground attenuation results in an overall drop-off rate of 4.5 dB per 

doubling of distance.

Atmospheric Effects

Receptors located downwind from a source can be exposed to increased noise levels relative to calm 

conditions, whereas locations upwind can have lower noise levels. Sound levels can increase at large 

distances (e.g., more than 500 feet) from a roadway because of atmospheric temperature inversion 

(i.e., increasing temperature with elevation). Other factors, such as air temperature, humidity, and 

turbulence, can also have significant effects.

Shielding by Natural or Human-Made Features

A large object or barrier in the path between a noise source and a receiver can substantially attenuate 

noise levels at the receiver. The amount of attenuation provided by shielding depends on the size of 

the object and the frequency content of the noise source. Natural terrain features (e.g., hills and dense 

woods) and human-made features (e.g., buildings and walls) can substantially reduce noise levels. 

Walls are often constructed between a source and a receiver for the specific purpose of reducing 

noise. A barrier that breaks the line of sight between a source and a receiver will typically result in at 

least 5 dB of noise reduction. Taller barriers provide increased noise reduction. Vegetation between a 

roadway and receiver is rarely effective in reducing noise because it does not create a solid barrier.

Fundamental Concepts of Ground-borne Vibration

This section describes basic concepts related to ground-borne vibration. In contrast to airborne sound, 

ground-borne vibration is not a phenomenon that most people experience every day. The background 

vibration velocity level in residential areas is usually much lower than the threshold of human 

perception. Most perceptible indoor vibration is caused by sources within buildings, such as 

mechanical equipment while in operation, people moving, or doors slamming. Typical outdoor sources 

of perceptible ground-borne vibration are construction equipment, steel-wheeled trains, and traffic on 

rough roads.
Construction activity can result in varying degrees of ground vibration, depending on the equipment 

and method used. Equipment such as air compressors, light trucks, and hydraulic loaders generate 

little or no ground vibration. Pile drivers, vibratory compactors, and demolition equipment have the 

potential to generate substantial vibration, which may present a concern if close to buildings (Federal 

Transit Administration 2006).

Dynamic construction equipment, such as pile drivers, can create vibrations that radiate along the 

surface and downward into the earth. These surface waves can be felt as ground-borne vibration. 

Vibration can result in effects that range from annoyance to structural damage. Variations in geology 

and distance result in different vibration levels with different frequencies and displacements. In all 

cases, vibration amplitudes decrease with increased distance from the vibration source.

As vibration waves travel outward from a source, they excite the particles of rock and soil through 

which they pass and cause them to oscillate. The actual distance that these particles move is usually 

only a few ten-thousandths to a few thousandths of an inch. The rate or velocity (in inches per second) 

at which these particles move is the commonly accepted definition of vibration amplitude, referred to 

as peak particle velocity (PPV).

Ground-borne vibration can also be expressed in terms of root-mean-square (RMS) vibration velocity 

to evaluate human response to vibration levels. RMS is defined as the average of the squared 

amplitude of the vibration signal. The vibration amplitude is expressed in terms of vibration decibels 

(VdB), which use a reference level of 1 micro-inch per second. Typical background vibration levels are 

between 50 and 60 VdB. The threshold of perception for most people is around 65 VdB. Vibration 

levels in the 70 to 80 VdB range are often noticeable but acceptable. Typically, vibration levels must 

exceed 100 VdB before building damage occurs. Historic structures, however, may have a damage 

threshold as low as 90 VdB.

The potential for annoyance and physical damage to buildings from vibration is the primary issue 

associated with ground-borne vibration. The human response to continuous ground-borne vibration is 

shown in Table A-2.

Table A-2. Human Response to Continuous Vibration

Peak Particle Velocity (inches/second) Human Response

0.4–0.6 Unpleasant

0.2 Annoying

0.1 Begins to annoy

0.08 Readily perceptible

0.006–0.019 Threshold of perception

Source: Whiffen and Leonard, 1971.

The damage potential thresholds associated with vibration generated by construction activities are 

shown in Table A-3.
Table A-3. Maximum Vibration Levels for Preventing Damage

Building Category

Limiting Velocity

(PPV in inches/ second)

Approximate Maximum

Vibration Level (VdB)

Reinforced concrete, steel, or 

timber (no plaster)

0.5 102

Engineered concrete and masonry 

(no plaster)

0.3 98

Non-engineered timber and 

masonry buildings

0.2 94

Buildings that are extremely 

susceptible to vibration damage

0.12 90

PPV = peak particle velocity.

VdB = root-mean-square velocity in decibels (1 micro-inch/second).

Source: Federal Transit Administration, 2006.

At higher frequencies, ground-borne vibration can be perceived as a noise source. At sufficiently high 

amplitudes, the propagation of vibration waves through the ground can cause building elements to 

vibrate at a frequency that is audible to the human ear. Ground-borne noise can rattle windows, walls, 

or other items that are coupled to building surfaces. Ground-borne vibration levels that result in groundborne noise are often experienced as a combination of perceptible vibration and low-frequency noise.

Land uses that are sensitive to ground-borne vibration include places where people reside, schools, 

libraries, and places of worship. Hospital operating rooms and certain types of industries that use 

vibration-sensitive equipment are considered highly sensitive to ground-borne noise and vibration. 

Outdoor park facilities, such as picnic areas or athletic fields, are not considered sensitive to groundborne noise or vibration.

The human response to different levels of ground-borne noise and vibration is shown in Table A-4. 

Vibration levels with spectral components within the range of human hearing (30 and 60 Hz in the 

table) produce corresponding A-weighted noise levels. Thus, it is possible to experience vibrations as 

audible noise, even though physical vibrations may not be detected.
Table A-4. Maximum Vibration Levels for Preventing Damage

Vibration Velocity 

(VdB)

Low-Frequency 

Noise Levela (dBA)

Mid-Frequency 

Noise Levelb (dBA) Human Response

65 25 40 Approximate threshold of perception for 

many humans. Low-frequency sound 

usually inaudible; mid-frequency sound 

excessive for quiet sleeping areas.

75 35 50 Approximate dividing line between barely 

perceptible and distinctly perceptible. 

Many people find transit vibration at this 

level annoying. Low-frequency noise 

acceptable for sleeping areas; midfrequency noise annoying in most quiet 

occupied areas.

85 45 60 Vibration acceptable only for an infrequent 

number of events per day. Low-frequency 

noise annoying for sleeping areas; midfrequency noise annoying for institutional 

land uses such as schools and churches, 

even with infrequent events.

VdB = vibration decibel

dBA = A-weighted decibel

a Approximate noise level when vibration spectrum peak is near 30 Hz

b Approximate noise level when vibration spectrum peak is near 60 Hz

Source: Federal Transit Administration, 2006
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