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5-112 VISUAL AND AESTHETICS 

Handling and storage of fuels and solvents will follow California OSHA and local standards for 

fire protection and prevention. These measures include appropriate storage of flammable liquids 

and prohibition of open flames within 50 feet of flammable storage areas. Additionally, a 

Hazardous Materials Management/Business Plan would have to be filed with the CCSF 

Department of Public Health in addition to the handling and storage procedures described above. 

This is essentially the permit for the storage of these materials at the site. 

5.16 VISUAL AND AESTHETICS 

Visual changes attributable to the construction of a new Transbay Terminal, Caltrain Downtown 

Extension and implementation of the Redevelopment Area are described in this section, with 

resulting changes to views currently enjoyed by residents and other users of the area. 

5.16.1 NO-PROJECT ALTERNATIVE

Under the No-Project Alternative, there would be no visual/aesthetic changes to the project area. 

The Transbay Terminal would remain in its current location and low-cost capital improvements 

would be made to the building. These improvements would most likely focus on the operational 

aspects of the Terminal, and it is unlikely that the Terminal’s aesthetic condition would be 

markedly improved. The Terminal would continue to obstruct southerly views from the north of 

the district, especially from Mission and Market Street. The existing elevated ramps to the 

Terminal would continue to loop through the area in their current position and would be 

retrofitted. The Caltrain rail service would terminate at the existing Fourth and Townsend 

station, and no tunnel would be constructed downtown.

5.16.2 TRANSBAY TERMINAL

The new Transbay Terminal would be constructed on the site of the existing Terminal at First 

and Mission Streets. A current concept for the new Terminal would be about 109 feet tall to its 

roofline, with ten cone-shaped roof elements that would reach up to 156 feet above the street 

level. Under the Loop Ramp Alternative, the new Terminal would be about one story shorter. 

The Terminal itself would generally occupy the same building footprint as the existing Terminal 

structure, but approximately 150 feet to the west. The Terminal would span parts of the First and 

Fremont street blocks, for a maximum length of 1,300 linear feet. The building’s horizontal 

orientation would contrast with the surrounding high-rise development, especially along its east 

(e.g., 100 Mission Street) and west sides (e.g. 199 Fremont Street). 

The design of the proposed Transbay Terminal building would be contemporary and could 

become a point of visual interest in the Transbay Redevelopment Area. The current concept for 

design of the new Terminal is shown in Figure 5.16-1. 
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VISUAL AND AESTHETICS 5-113 

Figure 5.16-1: Current Design Concept for Transbay Terminal Building 
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5-114 VISUAL AND AESTHETICS 

The structure would be constructed out of glass and other transparent elements, with the intent of 

allowing natural light to penetrate the inside of the Terminal building. Due to the transparent 

nature of the proposed building, views of the built environment outside the new Terminal 

structure may be possible from within. The use of transparent building materials and the coneshaped roof elements, along with gently curved roof-overhangs, would contribute to the visual 

identity of the area. A proposed plaza and landscaped pedestrian areas surrounding the Transbay 

Terminal to the east would visually enhance the pedestrian environment. 

Under the West Ramp and Loop Ramp Alternatives, ramps leading in and out of the Terminal 

and to and from the Bay Bridge would be either stacked or split. Figure 5.16-2 provides a visual 

simulation of the stacked ramps associated with the West Ramp Alternative. The ramp spans 

would be supported by columns and abutments and contain a constant cross-section throughout 

to give the appearance of a relatively thin structure through strong thin edge lines and imposed 

shadow. 

 Figure 5.16- 2: Visual Simulation of Stacked Ramps at Howard Street (West Ramp Alternative) 
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VISUAL AND AESTHETICS 5-115 

The proposed ramps would occupy considerably less area than the existing ramps, and would be 

split, breaking up the mass of the ramps and allowing views between the two new ramp sections. 

Although the new decks would be approximately 30 feet tall, they would be less visually 

intrusive due to their uniform appearance and minimal supporting structures. 

The southern and eastern portions of the existing ramp network would be demolished under the 

West Ramp Alternative, eventually opening up the eastward and southward views outside of the 

Transbay Redevelopment Area. Removing the eastern section of the ramps would open up 

eastward views along Howard Street toward the Bay and the East Bay Hills. Views toward 

Rincon Hill, currently obstructed by the southern loop of the existing ramp network, would be 

opened up along Beale, Fremont, and First Streets. This segment of the ramp network would not 

interrupt northern views from Rincon Hill into the Transbay Redevelopment Area. 

Under the Loop Ramp Alternative, such new views would not be possible, because the ramp 

network would be retrofitted and retained as it currently exists. 

5.16.3 CALTRAIN DOWNTOWN EXTENSION

Visual/aesthetic changes would occur with either of the Caltrain Downtown Extension 

alternatives. A fenced and open trench with concrete retaining walls dropping to some 30 feet in 

depth would be constructed south of Townsend Street and to the west of Fifth Street along the 

northern edge of the current Fourth and Townsend Yard. The alignment would enter a tunnel 

portal near Fifth Street and continue below grade to the Transbay Terminal. 

Construction of the cut-and-cover tunnel for the Caltrain Extension between Fifth Street and the 

Transbay Terminal would entail the acquisition and demolition of all existing buildings under 

which the alternative alignments would pass. Following construction of the underground 

extension, however, it is anticipated that new buildings would be constructed as vacant sites 

become available for resale. It is currently assumed that the new buildings would be similar or 

larger and higher than the buildings that are demolished on the sites. Other aesthetic effects 

would occur due to construction activities, and would be temporary in nature. 

The buildings in the Second and Townsend Street area would not be demolished but would 

rather remain under the Tunneling Option for either Caltrain Extension Alternative. For more 

information regarding potential construction-related effects, please see Section 5.21, 

Construction Impacts. 
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5-116 VISUAL AND AESTHETICS

5.16.4 REDEVELOPMENT

Development planned under the proposed redevelopment component would remove existing 

features with low visual value, including surface parking lots, and in some cases, deteriorated 

buildings, potentially enhancing the aesthetic quality of the Transbay Redevelopment Area. The 

overall character of the Transbay Redevelopment Area would continue to experience a change 

that has been underway for several years, from a predominately low-rise area dominated by early 

20th century industrial buildings and interspersed with surface parking lots, to a more dense 

urban area of newer mid- and high-rise buildings over 80-foot high bases, interspersed with 

designated areas of open space. 

Visual changes would occur under both redevelopment alternatives, in that the proposed 

redevelopment area would experience a relatively large increase in the number and size of 

buildings. Both the Full-Build and Reduced Scope alternatives would change the zoning on the 

former freeway parcels to allow for development at greater heights— up to a maximum building 

height of 400 feet on the north side of Folsom Street— 200 feet higher than is now permitted. 

An alternative urban design concept would produce taller and more slender structures with 

smaller floor plates. These structures could be on average up to fifty feet higher if developed to 

their full building-envelope potential. From an urban design standpoint, structures constructed 

under this alternative, while taller, would be less bulky and therefore would do more to preserve 

views. 

Even under the No-Project Alternative, the former freeway parcels would ultimately be expected 

to be developed, as rezoning from the current P (Public) use district could occur over time. The 

height limit might not be raised, however, so any development could occur at a lesser scale. 

With the West Ramp or Loop Ramp Alternative, development within and near the Terminal loop 

ramps would be expected to serve to some extent as a transition between the several office 

towers near Market Street and along Main and Spear Streets, and in the area south of Howard 

Street. This area now includes newer and renovated low- and mid-rise office, multi-media, and 

residential structures. Toward Market Street, there would likely be an increase in taller office 

towers, which would make up most of the office space anticipated in the Transbay 

Redevelopment Area, but whose visual effect would be lessened by the fact that these buildings 

would merely extend the downtown core and would not appear as a cluster of taller buildings in 

a low-rise environment. 

Changes would be noticeable in the area inside the existing Transbay Terminal loop ramps. In 

particular, if a new Terminal is built at the First and Mission site under the West Ramp 

Alternative, the existing ramps east of Beale Street would be demolished, encouraging the 

replacement of many older, smaller structures with new development at a larger scale. Changes 

are anticipated within the existing terminal ramps, as evidenced by recently completed 
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VISUAL AND AESTHETICS 5-117 

construction at Fremont and Howard Street (199 Fremont Street) and the Foundry Square project 

development at and near First and Howard Streets, currently under construction. 

Of the existing visually cohesive areas within the study area, the least change would come to the 

New Montgomery-Second Street Conservation District and South Park, where building height 

limits would remain lower than in surrounding areas and zoning controls that encourage 

preservation and reuse of existing buildings would remain in place. Development of surrounding 

blocks (north of the Bay Bridge approach), however, would be expected to bring closer the 

backdrop of office towers that has until recently been limited to the north end of the district. 

Folsom Street would undergo the most visible change in the district. The northern side of 

Folsom Street, from First to Spear Streets, would be developed with a mix of uses in structures 

that could range in height from 350 to 400 feet. 

Figure 5.16-3 shows a visual simulation of the possible redevelopment in this area. Provisions 

along Folsom Street would include widening the sidewalk and the creation of public open space 

along the street frontage to enhance the street-level pedestrian environment. This scenario is not 

an actual proposal but a representation of the types and levels of development that have been 

conceived for this portion of the Redevelopment Area. The simulation is of development as 

envisioned in the Draft Transbay Redevelopment Project Area Design for Development Vision 

(D4D), released by the San Francisco Redevelopment Agency in August 2003. Actual 

development proposals would be defined and evaluated and undergo individual environmental 

review, if necessary, in subsequent steps of the redevelopment process to make sure that the 

individual projects were covered. 

In addition to the widened north sidewalk of Folsom Street, it is anticipated that one or more 

large areas of open space would be provided in conjunction with the development of the 

Transbay Terminal and Redevelopment Area. Open space could be provided in the form of a 

public plaza, proposed to be located in front of the new Transbay Terminal on the western 

frontage of First Street, bounded by Mission Street to the north, Fremont Street to the east, and 

the proposed Terminal structure to the south. Other open spaces could add visual interest to midblock areas and provide a buffer to the planned development in the Transbay Redevelopment 

Area. 

Despite new construction, the Transbay Redevelopment Area would retain portions of its 

historic, smaller-scale development, notably in the New Montgomery-Second Street 

Conservation District. Second Street could also become a major visual pathway for pedestrian 

travel between downtown and the Transbay Redevelopment Area, and the adjacent 

neighborhoods of South Beach and China Basin. 
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5-118 VISUAL AND AESTHETICS

5.16.5 CHANGES TO SCENIC VIEWS OR VISTAS

Increased development would result in the loss of some existing views, particularly across the 

study area, rather than along the streets. View corridors would remain, however, particularly 

along Folsom Street with the planned building setbacks along the north side of the street. 

Depending on the outcome of the Transbay Terminal component, removal of some of the 

existing elevated ramps could open up views from within the area now visually walled off by 

these elements. The West Ramp Alternative has been identified for the Transbay Terminal 

component of the Locally Preferred Alternative (LPA). If the LPA is adopted as the project, this 

Transbay Terminal Alternative would remove the existing east loop ramp and open views to the 

east; new elevated ramps would be constructed in the same footprint as the existing west loop 

ramp. 

Figure 5.16-3 Simulation of Potential Redevelopment Sites and Scale 
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VISUAL AND AESTHETICS 5-119 

Views within and across the Transbay Redevelopment Area would generally be limited by new 

development. With the implementation of either the Full-Build or Reduced Scope alternative, 

possibilities for views across the district would be lessened. High-rises located in the Financial 

District north of the Transbay Redevelopment Area, which create a visual boundary between the 

Financial District and the generally lower-scale development south of Mission Street would 

gradually be developed within the Transbay Redevelopment Area. The clearly defined northern 

boundary of the Transbay Redevelopment Area would, over time, move southward, and the 

visual wall created by the existing high-rise development would become less pronounced when 

viewed from the Transbay Redevelopment Area. 

Block sizes in the Transbay Redevelopment Area are up to four times larger than the blocks 

north of Market Street. Under either the Full-Build or Reduced Scope Alternative, larger 

footprints and taller buildings would likely define new development, with the blocks generally 

less densely developed than those blocks north of Mission Street. Thus, even though it is likely 

that land uses would be intensified, there would likely be more space between the towers than on 

the blocks north of Market Street. New development within the Transbay Redevelopment Area 

would contain mid-block pedestrian passageways to further reduce the scale of the blocks. Inner 

courtyards and pedestrian plazas proposed as part of both Redevelopment Alternatives would 

visually enhance the streetscapes along Folsom Street for pedestrians. 

New development under either the Full-Build or the Reduced Scope Alternative would be 

required to follow urban design guidelines that the Redevelopment Agency would establish to 

enhance views and visual interest in the project area. New development proposed along Folsom 

Street would be set back 15 feet from the property line to preserve the existing view corridor 

(providing views of the Bay to the east) and to accommodate future landscaping, which would 

provide visual interest and create a green buffer against the traffic on the street. Under both 

alternatives, new towers would also have an 80-foot podium height, which would create an 

orderly and regular street wall. 

Under both Redevelopment Alternatives, proposed new development along Folsom and Howard 

Streets would consist of dual towers above their 80-foot base. This would decrease the mass of 

the buildings above their base levels and provide more views of the sky and surrounding 

development, as well as increase solar access to lower levels. Under one urban design 

alternative, new towers above their 80-foot base would have an approximate diagonal dimension 

ranging from 160 to 190 feet. Under the optional design alternative, new towers would have a 

diagonal dimension ranging from 126 to 156 feet. Thus, the second alternative would create less 

bulky buildings with smaller floor plates, which would appear taller and more slender than the 

development proposed under the first. However, because both design variants would employ 

setbacks and create a regular street wall at the ground level, given the scale of existing 

development surrounding the Transbay Redevelopment Area, effects on existing views would 

not be considered adverse. 
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5-120 VISUAL AND AESTHETICS

5.16.6 CHANGE IN THE CITYSCAPE

Potential changes to the San Francisco cityscape as a result of the proposed Redevelopment Area 

are shown in Figure 5.16-3. Views of the Transbay Redevelopment Area would become more 

differentiated as the stepping up of development heights towards downtown (north of Folsom 

Street) is realized. Assuming construction of the proposed Transbay Terminal and possible 

demolition of the eastern loop of the existing bus ramps, the wall that is composed of newer 

high-rise office construction would advance southward, with building heights decreasing towards 

Folsom Street. This change would be apparent from distant vantage points, such as from 

Dolores Park, Twin Peaks and Potrero Hill. 

Changes to the height and bulk in the Transbay Redevelopment Area from their current limits 

(see Table 5.1-1) would generally follow the urban design policies contained in the 

San Francisco General Plan. The proposed height limits, with the tallest buildings located in the 

north of the Transbay Redevelopment Area toward Market and Mission Streets and then 

decreasing somewhat from their maximum heights to between 350 to 400 feet along Folsom, 

would become gradually shorter south of Folsom Street. Moving east toward the Bay, height 

limits would gradually step down from a maximum of 400 feet along Folsom to approximately 

200 feet at Spear Street, then down to between 84 and 65 feet along The Embarcadero to protect 

views of the water.

Although the proposed new development would be expected to alter the existing aesthetic nature 

of the area, the visual features that would be introduced by the project are commonly accepted in 

urban areas and would not substantially degrade the existing visual quality or obstruct publicly 

accessible views. In addition, the Redevelopment Area’s provision for design amenities such as 

open spaces and landscape features, view corridor preservation, and pedestrian enhancement 

suitably address the proposed growth and ensure that the resultant effects would be 

predominately positive. For this reason, the project would not result in a demonstrable negative 

aesthetic effect and as such, no mitigation measures are proposed. 

5.16.7 LIGHT AND GLARE

New construction in the Transbay Redevelopment Area would generate additional night lighting 

in the area, but not in amounts unusual for a transportation hub in a developed urban area. As 

shown on Figure 5.16-1, the current concept for the Transbay Terminal entails the use of 

transparent building materials. This concept is intended to provide visual identity and increased 

security for passengers within the Terminal and in the surrounding pedestrian areas. 

New buildings and vehicles would also produce additional glare. This would not be expected to 

result in a substantial change unless buildings were constructed with reflective glass. Although 

perceived as an appealing design element to some, mirrored glass is more likely to generate 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.17 SAFETY AND SECURITY 5-121 

glare, and to create a potential annoyance and even safety hazard when directed by the sun 

towards the street or sidewalk. Mirrored glass is not permitted in San Francisco outside of 

redevelopment areas, per City Planning Code Resolution 9212; as a result, where it is used, it 

creates a more noticeable visual impact. Therefore, per the Design for Development, mirrored 

glass would not be permitted in the Transbay Redevelopment Area.

Although the proposed new development would be expected to alter the existing aesthetic nature 

of the area, the visual features that would be introduced by the project are commonly accepted in 

urban areas and would not substantially degrade the existing visual quality, obstruct publicly 

accessible views or generate obtrusive light or glare. In addition, the Redevelopment Area’s 

provision for design amenities such as open spaces and landscape features, view corridor 

preservation, and pedestrian enhancement suitably address the proposed growth and ensure that 

the resultant effects would be predominately positive. For this reason, no mitigation measures 

are proposed. 

5.16.8 DRAFT TRANSBAY REDEVELOPMENT AREA DESIGN FOR DEVELOPMENT VISION 

 (AUGUST 2003) 

All of the visual and aesthetic effects of the Draft Transbay Redevelopment Area Design for 

Development Vision would be similar to and less than those of the Full Build Alternative. 

Similar to the Full Build Alternative, the Design for Development Vision would contain towers 

over podiums and would create a continuous streetwall along Folsom Street. However, 

compared to the Full Build Alternative, each block of the Design for Development Vision would 

contain a single tall tower as a part of the Folsom Street frontage instead of two. Thus, the lessdense Design for Development Vision would have a more varied height pattern than would the 

Full Build Alternative because of a greater mix of building heights (65 feet to 550 feet). For that 

reason, the visual and aesthetic effects associated with the Design for Development Vision would 

be similar to, but less than those under the Full Build Alternative, and its effects also would not 

be substantially adverse. 

5.17 SAFETY AND SECURITY 

Safety refers to the prevention of accidents to the riding public, employees, or others present near 

the Transbay Terminal, Caltrain facilities, and in the Redevelopment Area. Transit vehicle 

accidents may be caused by events such as fires, faulty equipment, improper boarding or 

alighting of the transit vehicles or conflicts between trains, buses, automobiles, pedestrians, or 

non-motorized vehicles. Security refers to the prevention of unlawful acts resulting in harm to 

persons or damage to property. In a broader sense, it also implies freedom from threats or 

uncertainty about the likelihood of threatening acts. In this context, the No-Project Alternative 

does not present potential impacts; therefore, this section focuses on the proposed Project. 
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5-122 5.18 ENERGY

5.17.1 SAFETY AND SECURITY IN STATION AREAS 

The San Francisco Police and Fire Departments would be responsible for safety and security in 

the redevelopment area. This remaining discussion focuses on the rail and bus transit facilities. 

Passengers exiting the Transbay Terminal or the Caltrain stations at Fourth and Townsend would 

be transferring to another form of public transit or walking to their destination. The station and 

Terminal areas would be lighted and have designated walkways for pedestrians. 

Bus or rail passengers disembarking at the Terminal would gain access to other public 

transportation typically at the street level. There could also be an underground concourse 

connecting the Transbay Terminal and Train Station to the Embarcadero BART/Muni Metro 

Station at Market Street. Passengers disembarking at either station and walking to their 

destinations would use sidewalks and crosswalks. 

The separation of the AC Transit Buses and the Caltrain from the street levels would reduce the 

conflicts between these transit modes and pedestrians, except at the platform and bus loading 

areas. Pedestrian impacts are discussed in more detail in Section 3.4.1. 

Security at the Transbay Terminal would be the responsibility of the TJPA. Caltrain station 

security is currently provided by the JPB via its contract with Amtrak. Security would be 

increased over present levels commensurate with the increase in amount of activity at the 

Terminal and train station. The Terminal’s bus and train loading areas and passageways would 

be open and clearly lighted and clear sight lines would be maintained. Public security would not 

be adversely affected by operation of the Transbay Terminal or the Caltrain Extension and new 

station. 

Fire protection at the Terminal would be provided by the San Francisco Fire Department. Fire 

sprinklers, stand pipes, smoke/gas detectors and alarm systems would be placed throughout the 

Terminal and stations per City of San Francisco Fire Department requirements. Public fire 

safety would not be adversely affected by operation of Terminal or proposed Caltrain station. 

Refer to Section 5.21.17 on best construction management practices for the safety of 

construction workers, local residents, and employees during project construction. 

5.18 ENERGY 

Energy reliability and supply have become an increasing concern in California. The short-term 

situation has been very unstable for both price and availability of electricity and, to a lesser 

extent, natural gas. The Transbay Terminal/Caltrain Downtown Extension/Redevelopment 
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5.18 ENERGY 5-123 

Project would require energy to construct, operate, and maintain the transit facilities and for the 

redevelopment land uses. 

Energy for construction includes, in addition to the energy used by construction equipment and 

other activities at the worksite, the energy used to manufacture equipment, materials and 

supplied and transport them to the worksite. Energy consumed in the operation of transportation 

systems is primarily that used by vehicles transporting people or goods—propulsion energy—

plus ongoing energy use of operating facilities. Energy for maintenance includes that for day-today upkeep of equipment and systems as well as the energy embedded in any replacement 

equipment, materials, and supplies. 

Energy consumed in operation of transportation systems is typically referred to as direct energy. 

Energy consumed in construction and maintenance is referred to as indirect energy. Over the life 

of a transportation project, direct energy consumption is usually the largest component of total 

system energy use. Vehicle propulsion energy can amount to 60 percent of total system energy 

(Energy and Transportation Systems, Caltrans, Division of Engineering Services, July 1983). In 

the current environment, the ongoing energy requirements of new activities are of concern, 

including their long-term impacts on energy supplies. From an energy conservation standpoint, 

therefore, direct energy impacts are of more importance than indirect energy impacts. For these 

reasons, the energy analysis focuses on direct rather than indirect energy requirements of the 

Transbay Terminal/Caltrain Downtown Extension/Redevelopment Project. It compares 

estimated energy use in the regional transportation with and without the proposed project 

improvements. The analysis identifies the incremental change in transportation system energy 

use, including all major modes of ground transportation, associated with the project. 

Electricity. Caltrain trains operating over the approximately 1.2 mile rail extension would be 

electrically powered. A number of facilities in the tunnel segment, station, Transbay Terminal, 

and associated facilities would use electricity to power equipment. Currently the City and 

County of San Francisco owns and operates the Hetch Hetchy hydroelectric power generating 

facilities in the Tuolumne River watershed (in Yosemite National Park). These facilities supply 

the majority of electrical power to the city, which is delivered to users by Pacific Gas & Electric 

Company’s (PG&E) electrical transmission and distribution system. San Francisco does not 

require the full generating capacity of the Hetch Hetchy facilities and has entered into long-term 

power supply contracts with other agencies. Depending upon seasonal power generation 

capacity, contract obligations to others, local demand, and other circumstances, the city may 

receive power through the PG&E grid from other electrical generators, including PG&E itself. 

Redevelopment would use these or other currently available sources of energy. 

When electrified, Caltrain would receive power through the PG&E system. Whether the City 

and County of San Francisco would be the generator/supplier is unknown. Under deregulation, 

Caltrain would have the option to purchase from any generator/supplier with generating facilities 

in the western United States. Deregulation is intended to introduce competition into the local 
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5-124 5.18 ENERGY

supplier market to expand sources of power supply and ensure fair pricing. The structure of 

deregulation is open to scrutiny in California, however, as a consequence of the price and supply 

problems that became apparent in 2000. Although it is difficult to predict what changes may 

occur, it is anticipated that deregulation of the electric power market will be retained in some 

form. A number of power generating plants are under development in California and adjacent 

states by various private firms. The current supply problems and corresponding price volatility 

would diminish or disappear as these plants come online. Deregulation would allow Caltrain to 

contract with any number of generators/suppliers to ensure the long-term availability of power 

for operations, including operation of the Terminal/Extension Project. 

Other Energy Sources. The Transbay Terminal / Caltrain Downtown Extension / 

Redevelopment Project would require energy in the form of natural gas, gasoline, diesel fuel, and 

possibly other forms of energy for facilities and equipment operations (e.g., heating, lighting, 

ventilation, and operation of non-revenue equipment). For natural gas, PG&E owns the final 

delivery and distribution systems. PG&E purchases natural gas from various suppliers. Natural 

gas produced within the state of California has decreased to below 16 percent of demand and 

therefore other regions and countries are now the major source of supply (California Energy 

Commission web site: www.energy.ca.gov). As of October 2000, there were 38 

marketers/suppliers to the PG&E system. Despite some recent short-term volatility in gas prices, 

long-term supply is considered satisfactory. Interstate pipeline distribution systems have 

experienced capacity constraints; however, pipeline expansion is underway in some corridors 

and several applications for capacity additions are pending. Similarly for gasoline and diesel 

fuels, long term supply is not considered a critical issue; there are numerous suppliers. In the 

near term, refining capacity appears to be the major short-term constraint contributing to price 

volatility. Also, alternative fuel sources are emerging to provide substitute fuels for gas and 

diesel engines. 

Impacts. The Transbay Terminal/Caltrain Downtown Extension/Redevelopment Project would 

increase energy consumption for new land uses, train propulsion, and for transportation facility 

operations. However, it would also reduce the consumption of energy by other modes as a result 

of diverting travel from auto and bus to commuter rail service. 

Changes in direct energy use by the transit providers affected by the project were estimated for 

2020. Changes are relative to estimated energy use under the No-Project Alternative. The 

analysis evaluated travel patterns for three basic transportation modes: commuter rail; other 

transit in the form of bus; and auto as representative of roadway traffic. Commuter rail 

operations would increase with the Transbay Terminal/Caltrain Downtown Extension/ 

Redevelopment Project. The increase was quantified and expressed in terms of the additional 

vehicle miles of travel generated by operating 132 revenue trains a day along the approximately 

1.2 mile downtown extension. Adjustments were also made to account for increased nonrevenue movements and switching movements associated with operations on the extension. 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.18 ENERGY 5-125 

Some bus operations would be reduced somewhat because commuter rail would be extended to 

downtown San Francisco and provide a higher-level transit alternative. SamTrans, for example, 

is expected to be able to convert several express routes in the Caltrain Corridor to Caltrain 

feeders and not need to continue bus service to downtown San Francisco. San Francisco Muni 

may be able to reduce some existing shuttle service between downtown and Fourth and 

Townsend Streets. The analysis, to be conservative, assumed Muni service would be redirected 

and only included the more identifiable changes to SamTrans bus service. The potential 

reduction in bus trips was calculated by assuming express service in the immediate corridor 

would become Caltrain station feeders; trips were converted to vehicle miles saved by 

multiplying by the one-way travel distance between the proposed feeder station and downtown 

San Francisco. Auto travel in the corridor would also be reduced as more people diverted to 

commuter rail service. The reduction in auto travel was estimated by assigning a weighted 

average trip length for all diverted trips, assumed to be represented by the number of new riders 

on Caltrain with the extension in place in 2020. 

Table 5.18-1 provides a summary of estimated propulsion energy effects of the Transbay 

Terminal and Caltrain Downtown Extension for these modes. For a common standard of 

comparison, energy in the form of electricity or fossil fuels consumed (or saved) is converted to 

British thermal units (BTUs). Energy use is expressed in terms of the direct energy content of 

electricity and fuels consumed (or saved) at the final source as well as the total energy content of 

these energy units, which accounts for generation/refining and transmission/transport losses. For 

instance, a kWh has a final energy content of 3,416 BTUs; but an additional approximately 7,100 

BTUs of energy was required to generate, transmit and convert the kWh at its point of use. The 

total energy content of a kWh is estimated to be, therefore, approximately10,500 BTUs. 

While the increased travel distance for commuter rail trains would require an additional 

2.2 million kWhs annually, or 7.4 million direct BTUs and 22.7 million total BTUs, the savings 

in bus miles and auto vehicle miles no longer operated would be approximately 360 million 

direct BTUs and 430 million total BTUs. The net energy impact of the transit operations for the 

Transbay Terminal and Caltrain Extension would be an overall decrease, or savings, in 

propulsion energy use. 

In addition to the propulsion energy effects of the Terminal/Extension transit operations, the 

operation of the rail station, tunnel, and Transbay Terminal would result in ongoing energy use, 

mainly in the form of electricity for lighting, ventilation, communications, escalators/elevators 

for people transport, and heating/cooling. A general estimate of annual electricity use by these 

facilities is 2.5 million kilowatts, equivalent to 8,540 million direct BTUs and 26,250 million 

total BTUs of energy. 

There would be no offsetting reduction in energy use elsewhere; facilities energy represents a net 

new energy requirement. Adding the facility energy to propulsion energy requirements 

approximately doubles the energy consumed by the transit operations associated with the Project. 
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5-126 5.18 ENERGY

Table 5.18-1: Change in Propulsion Energy Consumption Resulting from 

Terminal/Extension Project (2020) 

Incremental Change from No-Project (Project Minus No-Project)

Model

Technology 

[1]

Energy Use 

Per Vehicle 

Mile [2]

Weekday 

Vehicle 

Miles

Annual 

Vehicle 

Miles3

Energy Units 

Consumed 

(Saved) 

Direct Energy 

Consumed [4] 

(Saved) 

in Millions of 

BTUs

Total Energy 

Consumed [5] 

(Saved) 

in millions of 

BTUs

Commuter 

Rail Electric 9.500 kWh 785 228,000 2,166,000 kWh 7,399.1 22,743.0 

Other 

Transit—

Bus 

Diesel 0.333 gal (3,600) (935,000) (311,667) gal (38,958.3) (44,802.1) 

Auto Gasoline 0.035 gal (260,000) (83,200,000) (2,912,000) gal (321,484.8) (385,781.8) 

Total All 

Modes (262,815) (83,907,000) (353,044.0) (407,840.9)

[1] Actual fleets may be mixed with more than one significant propulsion technology (e.g., diesel, CNG, or hybrid buses; 

gasoline or hybrid autos/trucks). The technology listed is considered representative for the entire mode and provides a 

reasonable approximation of energy use in BTUs. 

[2] Commuter rail electricity use rate is estimated consumption per passenger car mile for either electric locomotive propelled

fleet or electric multiple unit (EMU) fleet. It assumes a 10 percent reduction in consumption due to regeneration, i.e., the return 

of electrical current to the power system by braking vehicles. 

[3] Weekday forecasts of vehicle miles are annualized using the following factors: Commuter Rail = 290; Other Transit = 290; 

Auto = 320 

[4] Direct energy is that consumed by the end user--the rail locomotives, buses, and autos. Direct energy content of energy 

units is as follows: 

 1 kWh= 3,416 BTUs (British Thermal Units) 

 1 gallon diesel = 125,000 BTUs 

 1 gallon gasoline = 110,400 BTUs 

[5] Total energy includes the energy used to refine/generate and transport energy to the end user as well as the direct energy 

consumed, as follows: 

 1 kWh= 10,500 BTUs 

 1 gallon diesel = 143,750 BTUs 

 1 gallon gasoline = 132,480 BTUs 

Sources: Caltrain 25kV, 60Hz, ac Electrification Program, Overview of Preliminary Engineering Operating and Maintenance 

Costs, Parsons, July 2001; Nelson\Nygaard Consulting Associates; Parsons Transportation Group 

The combined propulsion and facilities electrical energy requirements would, however, still be 

more than offset by the estimated energy savings to other modes that result from the project 

(Table 5.18-1). New land uses under the Redevelopment portion of the Project would, however, 

consume additional energy.

No energy mitigation measures appear to be warranted. Moreover, current designs for the 

Transbay Terminal include “a wide ranging sustainable approach to the terminal building that 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-127 

uses the natural wind flows in downtown San Francisco to ventilate and cool the facility, 

harnesses solar energy for passive hearing and cooling, and established sustainability protocols 

for materials, construction procedures, and long-term building operations.” 28 Additional 

measures would be included in the design and specification of equipment to ensure energy 

efficiency, thereby helping to reduce the long-term energy requirements and the operating costs 

of the project. 

5.19 TRANSIT, TRAFFIC AND PARKING

Current transportation setting and projected No-Build conditions as well as projected Caltrain 

ridership and travel times for the Caltrain Extension Alternative are described in Chapter 3. 

Transportation impacts during construction are evaluated in Section 5.21.1. All other 

transportation effects of extending Caltrain to the Transbay Terminal Site are presented in this 

section.

5.19.1 TRANSIT OPERATIONAL IMPACTS

The Terminal/Extension Project includes two possible alignments for the Caltrain downtown 

extension, two design options for the new Transbay Terminal, and two scenarios for a 

redevelopment plan. In addition, there is an option for an underground pedestrian connection 

between the new Terminal and the Embarcadero BART station. 

With regard to transit operations, only the two alternatives for the Transbay Terminal design–the 

West Ramp and the Loop Ramp Alternatives–would have notably different effects on transit. As 

a result, this analysis of operating impacts is divided into two scenarios, one for each of the 

Transbay Terminal alternatives. The intermodal connections enabled by the pedestrian 

connection to BART are summarized at the end of this section. 

Impacts on transit operations would differ across the two terminal alternatives in terms of: 

• Terminal capacity 

• Bus access to the Transbay Terminal from the Bay Bridge 

• Bus access to the terminal from the street 

• Internal bus circulation within the Transbay Terminal 

• On-street bus circulation 

• Bus storage 

• Operating costs 

 

28 Transbay Terminal Improvement Plan, MTC, 2001, pg. 18.
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5-128 5.19 TRANSIT, TRAFFIC AND PARKING

Major operational differences between the two alternatives are described in Table 5.19-1. 

5.19.1.1 West Ramp Alternative 

The West Ramp Alternative would change the current configuration of how buses enter, exit, and 

park at the Transbay Terminal. Instead of traveling straight through the terminal and circulating 

back to the Bay Bridge along an external, aboveground loop, buses would turn around within the 

terminal using an internal loop. With the West Ramp Alternative, the on- and off-ramps 

connecting the terminal with the bridge would both be located at the west end of the terminal. 

The current operating distance from the bridge to the terminal back to the bridge is 6,500 feet. 

Under the West Ramp Alternative, this distance would increase to approximately 7,600 feet. 29 

It should be noted that this round trip distance is slightly longer than the similar path under the 

Loop Ramp Alternative because the terminal is slightly longer, owing to the use of two longer 

platforms rather than three somewhat shorter platforms.

Table 5.19-1: Operational Differences Between Transbay Terminal Alternatives 

Operational Issues Existing 

Terminal 

West Ramp 

Alternative 

Full Loop 

Alternative 

Total Number of Bus Bays 32 48 51 

Location of Bus Storage On-site Ramps Off-site storage 

lot 

On-site ramps and 

off-site storage lot 

Travel Distances (in Feet) 

Bay Bridge to Terminal to Bay Bridge 6,500 7,600 6,500 

Bay Bridge to Terminal to Storage Area (1) N/A 7,600 6,500 

Storage Area to Terminal to Bay Bridge (1) N/A 7,600 6,500 

Bay Bridge to Storage Area to Terminal to Bay Bridge (2) N/A 8,100 7,000 

From Ramp to Terminal 4,500 N/A 4,500 

Travel Times (in Seconds) 

Bay Bridge and Terminal to Bridge 216 317 227 

Bay Bridge to Terminal to Storage Area [1] N/A 329 243 

Storage Area to Terminal to Bay Bridge [1] N/A 334 240 

Bay Bridge to Storage Area to Terminal to Bay Bridge [2] N/A 350 255 

From Ramp to Terminal 60 N/A 60 

Notes: [1] Trip refers to deadheading. Since the existing terminal accommodates bus parking on-site, no deadheading or 

off-site staging is currently involved with AC Transit operations. 

[2] Trip refers to off-site staging at the bus storage area. Off-site staging is greatest for the West Ramp Alternative because 

there are only four to five on-site staging spaces on the ramps. 

Source: SMWM, Working Paper 4.1 Evaluation of Terminal Site Alternatives, January 2000. Travel times and distances 

were estimated by Fehr & Peers based upon preliminary terminal designs for the West Ramp and Full Loop Alternatives. 

 

29 SMWM Working Paper 4.1 Evaluation of Terminal Site Alternatives, (January 2000), p.37 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-129 

The existing east loop ramp leading from the Bay Bridge to the Transbay Terminal is currently 

used for midday-storage of AC Transit vehicles. The West Ramp Alternative would relocate AC 

Transit bus storage to an off-site area under the replacement Bay Bridge West Approaches, 

between Second and Third Streets. Storage of Golden Gate Transit buses would be moved from 

their current off-site storage at Main and Howard to beneath the Bay Bridge approaches between 

Third and Fourth Streets. 

AC Transit buses would operate independently of local traffic between the Bay Bridge, the 

storage area, and the Transbay Terminal. Direct connections would be provided on elevated 

ramps constructed along the Essex Street right-of-way in approximately the same location as the 

existing west loop ramps. With the buses entering and exiting the terminal from the west end 

only, the existing east loops would be permanently removed. 

The new Transbay Terminal would feature: 

• Three center island rail platforms supporting the six future tracks in the basement level. 

• Muni and Golden Gate Transit bus operations, patron entry, ticketing, joint development and 

a Greyhound store front on the street level. 

• Pedestrian concourse with retail/joint development that runs the full three-block length of the 

Terminal, one level above the street. 

• Thirty AC Transit bus bays serving a central platform two levels above the street. 

• A platform for Greyhound, paratransit and private operators on the top level or upper bus 

deck. 

Terminal Capacity. The West Ramp Alternative would significantly increase the passenger 

capacity of the Transbay Terminal. The new terminal would accommodate 35,000 rail and bus 

passengers during the peak hour. This is 11,000 more passengers than the 24,000 passengers 

projected for peak hour demand in 2020. The current peak hour passenger flow at the existing 

Terminal is 10,000 passengers. 30

The terminal would also accommodate significant increases in transit service. Currently, AC 

Transit’s highest peak utilization is 4.5 buses per bay per hour, which corresponds to average 

headways of 13.3 minutes per bay. The new terminal would accommodate eight-minute average 

headways at each of the 30 bus bays, thereby accommodating future demand and future 

growth.31 The West Ramp Alternative would increase the total number of bus bays from 32 to

48, with 30 on the AC Transit level and another 18 on the upper bus level. 

 

30 Arup, Working Paper 7.0 Pre-Concept Engineering Report, (April 2001), p. 5. 

31 Arup, p. 3-4
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5-130 5.19 TRANSIT, TRAFFIC AND PARKING

Bus Access to the Transbay Terminal from the Bay Bridge. Bus access to the terminal would 

no longer have separate points for entry and exit on opposite sides of the facility. Under the 

West Ramp Alternative, each of the two bus decks would have dedicated, fully grade-separated 

ramps leading from the Bay Bridge into the southwestern corner of the terminal. Although bus 

entrances would be provided on both the upper and lower bus decks, all buses would exit the 

Terminal from the lower deck. 

The lower level ramp entrance would have two lanes and provide AC Transit buses with an 

inbound and outbound connection to the Terminal’s lower bus deck. The upper level ramp 

entrance would have one lane and provide non-AC Transit buses with inbound access only to the 

terminal’s upper bus deck. Buses exiting from the upper deck would travel down a ramp at the 

east end of the structure to the AC Transit level and proceed through the AC Transit level to the 

bus exit. 

Buses from the East Bay would gain access to the stacked entrance ramps from the Bay Bridge 

using an exit at Fremont Street that also serves as a mixed-flow traffic off-ramp. The exit would 

lead to a two-way single-level bus ramp following the same alignment as the existing ramps. 

Just before the terminal, the ramp would split into the two levels for entry into either the lower or 

upper bus levels. 

Buses returning to the East Bay would use the two-way single level bus ramp upon exiting from 

the terminal. At the approach to the Bay Bridge the ramp would split into two levels to connect 

with the two-level bridge. East Bay buses would follow the eastbound bridge ramp and proceed 

onto the lower level of the bridge. 

Although requiring some future expansion, the ramp connecting the Bay Bridge with the 

Transbay Terminal would be designed to accommodate the potential implementation of light rail 

service from the East Bay. 

Bus Access to the Terminal from the Street. Like the current facility, a direct connection 

between the Terminal and the surface streets was determined to be unnecessary for bus 

operations.32 Some bus service, including paratransit operations, Greyhound, and other private 

tour operations, would be able to access the Transbay Terminal from city streets through the bus 

storage areas. 

Bus Circulation Inside the Transbay Terminal. The West Ramp Alternative adds an 

additional level to the Transbay Terminal’s system of bus circulation. AC Transit would board 

and alight passengers on the lower of the two bus decks (which include the top two levels of the 

terminal). Buses would circulate clockwise around a central passenger platform using either of 

 

32 Arup, p. 28 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-131 

two lanes: one for through traffic and one for turning in and out of the bus bays. The exit for the 

buses is located adjacent to the terminal entrance on the southwest corner, thus avoiding 

crossover. The deck would accommodate 30 bays including 26 for articulated buses and 4 for 

standard buses. The bays would be evenly divided between the northern and southern sides of 

the central platform. A saw tooth configuration has been adopted in accordance with AC 

Transit’s stated design criteria. 

The upper bus deck would be reserved for other transit operators, including Muni’s Line 108 to 

Treasure Island, paratransit services, Greyhound, and private operators. The upper bus deck 

would accommodate four saw tooth bays and 700 feet of straight curb on the northern side of the 

terminal – equal to about 18 additional bus bays. Buses would circulate along a single-sided 

passenger platform with two bus lanes: one through-lane and one turnout/parking lane. Unlike 

the lower level, the upper bus deck circulation is only a half loop, terminating on the east end of 

the terminal in a ramp that travels back down to the lower bus deck. 

The only vertical circulation between the two bus decks is the downward movement from the 

upper to the lower bus levels on a ramp forming the eastern face of the building. Occasional 

access from the lower deck to the upper deck would be possible through the external vertical 

circulation located in the bus storage areas. 

On-Street Bus Circulation Outside the Terminal. Muni lines 5, 6, 38, and 38L would no 

longer terminate at the Transbay Terminal’s “hump” on Mission Street between First and 

Fremont Streets. This loading area would be relocated to a mid-block passage under the terminal 

between Fremont and Beale Streets. Under this service scenario, Muni buses would operate as 

they currently do on Market/First and would then make a right turn onto Mission Street. All 

buses would alight passengers on Mission between First and Fremont Streets. Buses would then 

continue empty on Mission to Beale and make a right turn and enter the new loading area under 

the terminal, midblock between Mission and Howard. Assuming the implementation of a 

diamond (bus only) lane on Beale Street South of Mission Street and through the terminal’s 

designated Muni loading area, the rerouting would add about 40 seconds to the average travel 

time of buses.33

The new loading area would also provide Muni passengers with a direct link to the concourse 

level of the terminal. Sufficient platform and staging areas would be provided to accommodate 

Muni’s current routes plus at least one addition route. According to a bus operations simulation 

analysis, there would be excess capacity in two of the four aisles in the mid-block passage. A 

third aisle reserved for Muni’s 38 and 38L would operate near capacity. The fourth aisle, 

reserved for Golden Gate Transit, would also operate near capacity. Consequently, any 

 

33 Fehr and Peers Associates, Transbay Terminal Bus Operations Report, (September 2000), p. 10
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5-132 5.19 TRANSIT, TRAFFIC AND PARKING

significant expansions in Muni or GGT capacity would require the staging of buses at an 

alternate location.34 

Muni’s 14 line would continue to board and alight passengers at surface bus stops along Mission 

Street. Muni’s 10 and 76 lines would continue to load passengers at curbside bus stops along 

First and Fremont Streets. No significant change in operations would result from the West Ramp 

Alternative. 

Inbound Golden Gate Transit Basic Service buses, which operate on Mission Street, would 

continue to terminate in front of the Transbay Terminal on Mission Street. The proposed 

Transbay Terminal mid-block boarding area would be used as the first revenue stop by outbound 

GGT Basic Service buses. 

Inbound Golden Gate Transit Financial District Commute Service buses would continue to serve 

the Transbay Terminal by the bus stop on First Street, between Market and Mission Streets. 

Outbound Commute Service would continue to load passengers along Fremont Street between 

Mission and Market and between Mission and Folsom. 

Bus Storage Areas. AC Transit currently stores all of its transbay buses laying over midday in 

San Francisco on the existing Transbay Terminal access ramps. Under the West Ramp 

Alternative, minimal bus staging and bus parking would be possible on the new access ramps. 

Instead, an off-site storage area would be located below the west approaches to the Bay Bridge 

between Second and Third Streets. Access to the storage area would be by a ramp connection to 

the two-way Bay Bridge/Transbay Terminal ramp. The area beneath the Bay Bridge is currently 

used for automobile parking. 

AC Transit’s bus storage lot would be at-grade with sufficient area to permit parking and 

circulation in accordance with AC Transit’s projected future needs. Depending on the layout and 

operation of the bus storage area, up to 54 buses could be accommodated at-grade with fully 

independent access provided each parked bus; another nine buses could be parked on the access 

ramp. According to a bus operations simulations analysis developed for the supplemental air 

quality analysis, even with assumptions of 50 percent growth in AC Transit service, there would 

be a maximum of 70 buses (including those circulating) in the storage facility during the 45 

minute peak period for bus parking and staging.35 

Golden Gate Transit buses would be provided bus storage space under the Bay Bridge west 

approaches between Third and Fourth Streets. Access to the lot would be via the same ramp 

connection to the AC Transit storage lot and an at-grade mid-block crossing of Third Street. 

 

34 Fehr and Peers Associates, p. 10 35 Supplemental Air Quality Analysis, Terry A. Hayes Associates, LLC, 2003.
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.19 TRANSIT, TRAFFIC AND PARKING 5-133 

Approximately 140 buses could be accommodated at an at-grade paved lot. It would be 

occupied by Golden Gate Transit weekdays only and available for other uses in the evening and 

on weekends. 

Approximately 43,000 square feet of space at the western end of the Golden Gate Transit storage 

area would be available for a single deck parking structure. This would allow approximately 300 

public parking spaces to be built contiguous to the storage area. 

Operating Costs. The annual operating costs for AC Transit would be higher under the West 

Ramp Alternative than under either the existing operation or the Full Loop Alternative (see 

below). Table 5.19-2 shows that the estimated annual operational and maintenance costs for AC 

Transit would be approximately $1.3 million under the West Ramp Alternative, assuming no 

growth in service. This is about 40 percent higher than the estimated $939,000 for current AC 

operations.

Table 5.19-2: Estimated AC Transit Annual Operating Costs 

Scenario 

Increase (Existing) Operating Costs Maintenance 

Costs Total Costs % 

Existing $ 508,972 $430,285 $939,257 

West Ramp Alternative $774,939 $530,839 $1,305,779 39%

Full Loop Alternative $559,002 $455,468 $1,014,469 8% 

The cost analysis is based upon AC Transit's 1998-99 cost model, which indicates a marginal cost of $44 per 

hour and $1.78 per mile. 

Source: SMWM, Working Paper 4.1 Evaluation of Site Terminal Alternatives, January 2000. Analysis is 

based on the demand assumptions described in Table 5.19-3. 

The cost analysis shown in Table 5.19-2 is based on AC Transit’s 1998-99 cost model, which 

indicates a marginal cost of $44 per hour and $1.78 per mile. The demand assumptions used to 

determine costs are shown in Table 5.19-3.

Operating costs for Golden Gate Transit would be lower for both Transbay Terminal options 

than under the existing conditions, given that the permanent bus storage facility would be closer 

to the Transbay Terminal than Golden Gate Transit’s existing bus storage facility at Eighth and 

Harrison streets. 

5.19.1.2 Full Loop Ramp Alternative 

The Full Loop Ramp Alternative would not significantly change existing bus access and 

circulation between the Transbay Terminal and the Bay Bridge. Although a new terminal 

facility would be constructed, the location of the new loop ramps between the terminal and the 
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5-134 5.19 TRANSIT, TRAFFIC AND PARKING

Bay Bridge would be generally the same. Unlike the West Ramp Alternative, AC Transit bus 

staging and storage would continue to be on the ramps with some additional off-site parking 

under the Bay Bridge’s western approach at Second Street. 

Under the Loop Ramp Alternative, the Transbay Terminal would feature:

• Three center island rail platforms supporting the six future tracks in the basement level. The 

street level would support patron entry, ticketing, and joint development. 

• Street level bus service for Muni and Golden Gate would be provided in the block east of 

Beale Street (as opposed to the mid-block crossing between Fremont and Beale as proposed 

in the West Loop Alternative). 

• A single elevated bus deck would accommodate the entire AC Transit transbay operation 

and all other bus services using the direct access ramps to and from the Bay Bridge. A total 

of 51 bus bays would be served by three one-way bus lanes. 

Terminal Capacity. The terminal would be designed to accommodate the 35,000 transit 

passengers expected in the terminal during the peak hour in 2020. A bus operations analysis 

similar to the one conducted for the West Ramp Alternative was not conducted for the Full Loop 

Alternative. However, the Full Loop calls for 51 bus bays compared to the West Ramp’s 48 bus 

bays. The latter number was determined to be more than adequate for projected terminal 

utilization by AC Transit in the foreseeable future. 

Bus Access to the Transbay Terminal from the Bay Bridge. Under the Full Loop Alternative, 

bus connections between the Transbay Terminal and the Bay Bridge would be the same as today. 

There would be no changes in the loop circulation of the existing connecting bus ramps. 

Westbound buses would exit the Bay Bridge onto a ramp leading directly to the Transbay 

Terminal, proceed through the east end of the terminal building, and follow the looping ramp 

above city streets back to the Bay Bridge’s approach for eastbound vehicle access 

Bus Access to the Terminal Area from the Street. The new bus ramps would not require any 

change in terminal access at street level. However, Muni service currently terminating at the 

Terminal’s “hump” on Mission Street would be relocated to a new staging area east of Beale 

Street as in the West Ramp Alternative. 

Internal Bus Circulation within the Transbay Terminal. The Transbay Terminal is currently 

configured with three lanes and buses load parallel to the curb. However, to accommodate AC 

Transit’s preferred standard of saw tooth bus bays, the Full Loop Alternative would have three 

one-way bus lanes serving 51 bus bays. The bus structure would be somewhat longer than the 

existing terminal to accommodate the increased number of bays and the reduced number of 

lanes. 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-135 

On-Street Bus Circulation. Muni lines 5, 6, 38 and 38L would board and alight passengers at a 

new loading area east of Beale Street and north of Howard Street. As with the West Ramp 

Alternative, buses would need to continue two extra blocks along Mission Street to access the 

terminal area through Beale Street. There would not be substantial changes in the existing onstreet circulation of Golden Gate Transit and SamTrans under the Full Loop Alternative. 

Bus Storage. AC Transit buses would continue to be staged on the ramps with parking available 

on the east side of the ramps. Additional storage for both AC Transit and Golden Gate Transit 

would be available beneath the western approach of the Bay Bridge at Second Street. 

Operator Costs. As shown in Table 5.19-2, operating and maintenance costs for AC Transit 

would not be significantly higher under the Full Loop Alternative than under the existing 

situation. Combined annual costs would be approximately $1.01million or 8 percent higher than 

the $939,000 required for existing operations. 

Operating costs for Golden Gate Transit would be lower for both Transbay Terminal options 

than under the existing conditions, given that the permanent bus storage facility would be closer 

to the Transbay Terminal than Golden Gate Transit’s existing bus storage facility at Eighth and 

Harrison streets. 

5.19.1.3 Intermodal Connectivity 

Mezzanine. The West Ramp and Loop Ramp Alternatives would include a below-grade 

mezzanine. The mezzanine would be constructed between the terminal’s ground floor and the 

rail platforms. Its configuration would consist of a simple bridge spanning across the platforms 

or a large floor area. The mezzanine would allow consolidation of the vertical circulation 

elements down from ground level and greatly increase the flexibility of the ground floor layout. 

A rail mezzanine would enable escalator access between the upper bus decks, the street-level 

Muni loading area, and below ground rail platforms. The mezzanine could also facilitate a direct 

underground connection between the western end of the Transbay Terminal and a proposed 

Muni Third Street light rail station. By situating this connection at an underground mezzanine 

instead of along raised platforms of an on-street alignment, pedestrian movements would not be 

disrupted on the aboveground street grid (see Section 5.21.4).36 The mezzanine would have no 

adverse effects on bus operations in the terminal or at street level. 

Pedestrian Tunnel between Transbay Terminal and Market Street. The option for a 

pedestrian tunnel to Market Street under both terminal design alternatives would create a 

passageway between the Terminal and the Market Street subway. For either terminal alternative, 

the connection would be built below Fremont Street, providing a sheltered passenger connection 

 

36 SMWM Working Paper 12 Terminal Design Modifications and Refinements, (March 2001), p. 40.
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5-136 5.19 TRANSIT, TRAFFIC AND PARKING

between AC Transit bus service, Caltrain, Greyhound and the Muni/BART underground rail 

lines. The pedestrian tunnel is not anticipated to affect bus operations substantially although 

there is the potential for street bus movements, as for street traffic, to experience fewer conflicts 

and delays at intersections from reduced pedestrian volumes at crosswalks.

5.19.2 IMPACTS ON CORRIDOR TRANSIT PATRONAGE

The Transbay Terminal/Caltrain Downtown Extension Project would increase linked transit trips 

in the region in the year 2020 by an estimated 10,000 trips per day, from about 728,000 to 

738,000 trips per day. As defined for this project, a linked transit trip consists of two or more 

unlinked trips, i.e., transit trips that involve two or more vehicles or modes. Thus an increase in 

linked transit trips in the corridor indicates that more people are choosing to use Caltrain instead 

of non-transit modes, compared with the No-Project Alternative. 

Preliminary estimates of the transit mode shares have been made. The current transit mode share 

for work trips between San Mateo County and San Francisco is estimated to be 15.4 percent. 

Between Santa Clara County and San Francisco, the transit mode is estimated to be 13.1 percent. 

By 2020, these transit mode shares are expected to rise to 19.7 and 22.3 percent, respectively. 

With the Terminal/Extension Project, these transit mode shares are projected to be 22.2 and 

28.5 percent, respectively. 

5.19.3 IMPACTS ON OTHER TRANSIT SERVICES

The Caltrain Extension would provide a terminus that is in downtown San Francisco and the 

Financial District. Current bus shuttles between these areas and the existing Caltrain terminus at 

Fourth and Townsend Streets would be eliminated or rerouted, with possible corresponding 

reductions in Muni’s operating costs. With the extension, Caltrain would also provide better 

service to downtown San Francisco for some trip makers than would BART and SamTrans, with 

attendant patronage impacts on these systems. The Caltrain Extension would also have longterm impacts on transit services that currently utilize the Transbay Terminal. 

5.19.3.1 BART 

Ridership forecasts predict that the Transbay Terminal/Downtown Caltrain Extension Project 

would result in a 11 percent reduction in BART entries and exits in San Mateo County (at the 

Daly City, Colma, Hickey, Tanforan, SFO, and Millbrae BART stations). The analysis indicates 

that in 2020, there would be about 5,700 daily transfers between BART and Caltrain at the 

Peninsula intermodal transfer facility in Millbrae under the No-Build Alternative, and that this 

number would drop by about 4,400 (78 percent) if Caltrain were extended into downtown San 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-137 

Francisco. An additional 700 transfers per day between BART and Caltrain is projected to occur 

in downtown San Francisco under the Terminal/Extension Project. 

5.19.3.2 Muni 

The following assumptions about Muni bus route changes with the Caltrain Extension 

Alternative were made: 

• Regarding the 30-Stockton and 45-Union, one of these will continue to serve Third and 

Fourth Streets between Market and Townsend, and will be extended into Mission Bay. The 

other will likely be terminated in the vicinity of Yerba Buena Center. 

• The 10 Townsend/47 Van Ness- would be rerouted to run along Harrison Street and Bryant 

Street between Fifth Street and Main Street. 

• The 76-Marin Headlands and the 82X-Levi Plaza Express would be truncated and rerouted to 

serve the Transbay Terminal area. 

The changes in Muni service are predicted to result in a reduction in annual revenue-hours and 

revenue-miles for Muni of 15,700 hours and 151,100 miles, respectively, resulting in an annual 

net cost savings of about $1.4 million. Muni would also reduce its peak fleet demand by four 

buses. In addition to re-routing existing Muni service to Caltrain’s Fourth and Townsend Streets 

terminal, the existing Muni shuttle service (81x, 80x) to the Caltrain terminal could be eliminated 

saving the JPB approximately $558,000 for Muni shuttle service savings per year. Muni Metro 

N-Judah LRT service to Fourth and King Streets is assumed to continue to service to all stops 

south of the Embarcadero Station, including the reconfigured Caltrain station and the Third 

Street LRT extension, which is currently under construction. 

Ridership forecasts predict that the Transbay Terminal/Downtown Caltrain Extension Project 

would result in a four percent decrease in Muni ridership.

5.19.3.3 SamTrans 

The extension of Caltrain would also decrease the need for SamTrans express bus service from 

the Peninsula to the Transbay Terminal. SamTrans express routes including the KS, MX, NX, 

PX, RX, and TX would likely be eliminated. Consequently, the extension of Caltrain into 

downtown is projected to result in a reduction of 2,000 passengers in SamTrans daily bus 

ridership where a SamTrans bus was the primary mode of travel. Trips that use a SamTrans bus 

to gain access to a Caltrain or BART station are not included in this estimate. Additionally, local 

SamTrans routes would continue to serve downtown San Francisco in the Transbay Terminal 

area. This reduction in service would decrease SamTrans annual revenue-hours and revenuemiles by 16,500 hours and 405,200 miles, respectively. SamTrans would also require 32 fewer 

buses during the peak periods of operation. This would result in a $2.6 million reduction in 

annual operating and maintenance costs for Sam Trans. 
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5-138 5.19 TRANSIT, TRAFFIC AND PARKING

Ridership forecasts predict that the Transbay Terminal/Downtown Caltrain Extension Project 

would result in a three percent reduction in SamTrans bus ridership.

5.19.3.4 AC Transit 

A substantial change in AC Transit ridership was not projected by the model for the Transbay 

Terminal/Caltrain Downtown Extension/Redevelopment Project, although some increase in 

ridership is predicted due to the complementary nature of the Downtown Caltrain Extension. 

Extending Caltrain to the Transbay Terminal would likely encourage transfers from Caltrain to 

AC Transit buses, thereby increasing AC Transit bus ridership somewhat. 

5.19.3.5 Golden Gate Transit 

A substantial change in ridership on Golden Gate Transit was not projected by the model for the 

Transbay Terminal/Caltrain Downtown Extension/Redevelopment Project, although the 

increased proximity of the Caltrain terminal to Golden Gate Transit bus routes could increase 

the number of transfers from Caltrain to Golden Gate buses, thereby increasing Golden Gate 

bus ridership. 

The proposed permanent off-site storage facility for Golden Gate Transit bus operations beneath 

the Western Approach of the Bay Bridge would be closer to the Transbay Terminal than Golden 

Gate Transit’s existing bus storage facility at Eighth and Harrison streets. This will result in 

reduced deadheading and operating costs for Golden Gate Transit buses that layover at the 

storage facility between runs. 

5.19.3.6 Other Transit Operators 

Ridership forecasts predict that VTA ridership would decrease by two percent. However, 

Greyhound and other operators in the Transbay Terminal could potentially have their ridership 

enhanced by the closer connection with Caltrain. 

5.19.4 IMPACTS ON VEHICULAR TRAFFIC 

5.19.4.1 Travel Time Impacts in Caltrain Corridor 

The ridership analysis projected that the Terminal/Extension Project would have a beneficial 

impact on traffic congestion. In every case, auto travel times in the A.M. peak period are 

expected to decrease under the Terminal/Extension Project. In 2020, the travel time 

improvements between origins in the U.S. 101 corridor and San Francisco are expected to 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-139 

typically be from two to four minutes37. Relocating Caltrain’s San Francisco terminus to the 

Transbay Terminal area is expected to result in a seven percent reduction in the number of 

person hours of vehicle travel.38 Morning peak hour delay is expected to be reduced by 20 

percent. Implementation of the Terminal/Extension Project would result in daily travel time 

savings of 7,200 person hours, which includes 5,700 person hours saved for Caltrain riders and 

1,500 person hours for roadway travelers in the corridor. Using FTA procedures, this represents 

an approximate $20 million per year savings (7,200 hours/day X $11.26/hour X 250 work 

days/year). 

5.19.4.2 Vehicle Miles Traveled (VMT) Impacts in the Caltrain Corridor 

Year 2020 vehicle miles traveled (VMT) on all roadways in the corridor is projected to decrease 

by 0.2 percent from 145,934,000 to 145,674,000 VMT, a savings of 260,000 VMT with the 

Terminal/Extension Project compared with the No-Project conditions 

5.19.4.3 Intersection Level of Service Impacts around the Transbay Terminal 

The San Francisco County Transportation Authority (SFCTA) countywide travel demand 

forecasting model (SFCTA Model) was used to develop the travel forecasts for development and 

growth through the year 2020 in the region, as well as to determine travel demand to and from 

the South of Market area (area roughly bounded by The Embarcadero, Market Street, South Van 

Ness Avenue and King Street). This approach results in an impacts assessment for year 2020 

conditions that takes into account both the future development expected in the South of Market 

area, as well as the expected growth in housing and employment for the remainder of San 

Francisco and the nine-county Bay Area. The most up-to-date version of the SFCTA Model 

estimates future traffic and transit travel demand for the entire nine-county Bay Area region 

based on land use and employment forecasts prepared by the San Francisco Planning Department 

for the county, plus regional growth estimates developed and adopted by the Association of Bay 

Area Governments (ABAG) in 1998 (Projections ’98) for the remainder of the Bay Area region. 

Travel demand was estimated for three land use scenarios: 

• 2020 No-Project, which assumed future development and growth, consistent with the ABAG 

forecasts for San Francisco and the Bay Area, and incorporates projects that have recently 

been approved or entitled in the South of Market area. 

• 2020 Project, which included the additional development associated with the 

Terminal/Extension Project. 

 

37 Ridership Forecasting Results Report, Korve Engineering, Inc., May 29, 1996. Adjusted to 2020 conditions by PTG, 

September 2001. 

38 August 27, 1996 memo from Korve Engineering to ICF Kaiser Engineers. 
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5-140 5.19 TRANSIT, TRAFFIC AND PARKING

• 2020 Cumulative, which incorporated other plans recently proposed in the South of Market 

area including the Rincon Hill Rezoning and the South of Market Redevelopment Area Plan, 

the Mid-Market Redevelopment Area Plan, as well as the Transbay Terminal / Downtown 

Caltrain Extension Project. As a result, the year 2020 cumulative conditions forecasts used 

in the analysis exceed the ABAG forecasts for San Francisco for employment by about 2.8 

percent, and household population by about 1.4 percent. 

An analysis for adverse effect from the project’s impact to intersections within the project area 

was performed for the existing plus project and cumulative conditions. Table 5.19.3 shows all 

intersections with an adverse effect and notes all intersections that have a level of service (LOS) 

of E or F under the existing plus project and cumulative conditions (see also Table 5.19-4). 

Under the City and County of San Francisco criteria, an adverse effect would occur if an 

intersection is degraded to a LOS of E or F. For an intersection that operates at LOS E or F in 

the without project conditions, there may be an adverse impact depending upon the magnitude of 

the project’s contribution to the worsening of delay. In addition, a project would have an 

adverse effect if it would cause major traffic hazards, or would contribute considerably to the 

cumulative traffic increase. For the purpose of this project, existing conditions are assumed to 

be year 2020 baseline, existing plus project is the 2020 baseline plus the Transbay Terminal 

project, and cumulative is the cumulative that includes all of the related City and Redevelopment 

projects. 

Table 5.19-3: Project Impact Determination for Intersections at LOS E or 

F Under 2020 Baseline Plus Project and 2020 Cumulative Conditions 

Intersections 2020 Baseline Plus Project 2020 Cumulative 

First/Market Adverse Effect Adverse Effect 

First/Mission Adverse Effect Adverse Effect 

First/Howard Adverse Effect Adverse Effect 

Fremont/Howard Adverse Effect Adverse Effect 

Beale/Howard Adverse Effect Adverse Effect 

Second/Folsom Adverse Effect Adverse Effect 

First/Folsom Not an Adverse Effect Not an Adverse Effect 

The Embarcadero/Folsom Not LOS E or F under Existing Plus Project Not an Adverse Effect 

Second/Harrison Not an Adverse Effect Not an Adverse Effect 

Harrison/Essex Not an Adverse Effect Not an Adverse Effect 

Harrison/First Not an Adverse Effect Not an Adverse Effect 

Harrison/Fremont Not an Adverse Effect Not an Adverse Effect 

Main/Harrison Not an Adverse Effect Not an Adverse Effect 

Second/Bryant Adverse Effect Adverse Effect 

Source: San Francisco Planning Department, January 2002.
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TRANSIT, TRAFFIC AND PARKING 

Table 5.19-4: Intersection Level of Service -- Existing and 2020 Conditions, Weekday P.M. Peak 

Existing 2020 No-Project 2020 Term./Ext. Project 

Intersection 

Delay LOS v/c Delay LOS v/c Delay LOS v/c D

1. First/Market 25.9 D – 34.9 D – 54.9 E 1.16 >2. Fremont/Market 15.2 C – 26.0 D – 30.3 D – 33. Second/Mission 10.2 B – 16.1 C – 21.1 C – 34. First/Mission 27.1 D – 58.5 E 1.13 >60 F 1.22 >5. Fremont/Mission 21.8 C – 21.9 C – 29.2 D – 36. Beale/Mission 14.9 B – 19.9 C – 33.0 D – 37. Main/Mission 15.6 C – 20.3 C – 22.6 C – 28. Second/Howard 15.1 C – 25.9 D – 25.1 D – 29. First/Howard 31.9 D – 40.9 E 1.09 >60 F 1.21 >10. Fremont/Howard 20.1 C – 28.7 D – 44.3 E 1.03 411. Beale/Howard 16.2 C – 28.1 D – >60 F 1.19 >12. Main/Howard 15.4 C – 25.1 D – 33.7 D – 313. Spear/Howard 13.9 B – 15.5 C – 31.7 D – 314. Second/Folsom 32.5 D – >60 F 1.15 >60 F 1.18 >15. First/Folsom >60 F 1.17 >60 F 1.15 >60 F 1.21 >16. Fremont/Folsom 7.7 B – 22.4 C – 25.5 D – 217. Beale/Folsom 14.5 B – 14.7 B – 15.8 C – 118. Main/Folsom 12.1 B – 15.9 C – 34.6 D – 319. Spear/Folsom 11.1 B – 13.2 B – 14.1 B – 120. The Embarcadero/Folsom 18.2 C – 26.5 D – 39.0 D – 421. Second/Harrison 44.9 E 1.11 >60 F 1.19 >60 F 1.26 >22. Essex/Harrison >60 F 1.15 >60 F 1.17 >60 F 1.18 >23. First/Harrison >60 F 1.26 >60 F 1.23 >60 F 1.29 >24. Fremont/Harrison 36.2 D – 49.5 E 0.93 59.1 E 0.96 >25. Main/Harrison 32.0 D – 40.9 F 0.83 56.1 F 0.89 >26. Spear/Harrison 15.4 C – 30.4 C – 31.9 D – 327. Second/Bryant >60 F 1.18 >60 F 1.23 >60 F 1.28 >Notes: Delay presented in seconds per vehicle. v/c = volume-to-capacity ratio for all intersections at LOS E or F. Source: Wilbur Smith Associates, December 2001 
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2020 Baseline Plus Project Conditions. As shown in Table 5.19-4, the project’s traffic 

contribution to the following intersections would be considered not adverse under the baseline 

plus project conditions: 

• First/Folsom 

• Second/Harrison 

• Harrison/Essex 

• Harrison/First 

• Harrison/Fremont 

• Main/Harrison 

This was determined based on an examination of the traffic volumes for the traffic movements 

that determine overall LOS performance at these intersections. In most intersections where 

baseline plus project conditions were found to be not adverse, the project would add traffic 

movements that would continue to operate satisfactorily. In some instances, the project would 

add vehicles to movements at intersections that would not perform well under the 2020 baseline 

plus project conditions. However, in these instances, the project’s contributions to these 

movements would be small. Finally, in one case, no adverse contribution was found because the 

project volumes and total volumes for the movement would be very small and would not 

materially affect the overall LOS performance at the affected intersection. For the intersections 

listed above, project traffic would also not represent a considerable contribution to the 2020 

baseline plus project conditions, and the project would not have an adverse traffic impact at these 

intersections. 

As shown in Table 5.19-4, the project’s contribution to the following intersections would be 

considered adverse under the 2020 baseline plus project conditions: 

• First/Market 

• First/Mission 

• First/Howard 

• Fremont/Howard 

• Beale/Howard 

• Second/Folsom and 

• Second/Bryant 

The project would add substantial numbers of vehicles to some movements that determine 

overall LOS performance. Specifically, the project would add vehicles to movements that 

represent a considerable contribution to the baseline plus project traffic conditions and the 

project would have an adverse impact on these intersections. 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-143 

2020 Cumulative Condition: As shown on Table 5.19-4, the project’s traffic contribution to the 

following intersections would be considered not adverse under 2020 cumulative conditions. 

• First/Folsom 

• Second/Harrison 

• Harrison/Essex 

• Harrison/First 

• Harrison/Fremont 

• Main/Harrison 

This was determined based on an examination of the traffic volumes for the traffic movements 

that determine overall LOS performance at these intersections. In most instances where 

cumulative conditions were found to be not adverse, the project would add vehicles to 

movements that would continue to operate satisfactorily. In some instances, the project would 

add vehicles to movements at intersections that would not perform well under cumulative 

conditions. However, in these instances, the project’s contribution to these movements would be 

small. Finally, in one case, no adverse contribution was found because the project volumes and 

total volumes for the movements would be very small and would not materially affect overall 

LOS performance at the affected intersection. For the intersections listed above, project traffic 

would not represent a considerable contribution to the cumulative conditions, and the project 

would not have an adverse traffic impact at these intersections. 

As shown in Table 5.19-4, the project’s contribution to the following intersections would be 

considered adverse under 2020 cumulative conditions (these are the same intersections that 

would experience adverse effects under the 2020 plus project condition): 

• First/Market 

• First/Mission 

• First/Howard 

• Fremont/Howard 

• Beale/Howard 

• Second/Folsom and 

• Second/Bryant 

For these intersections, the project would add substantial numbers of vehicles to some 

movements that determine overall LOS performance. Therefore, the project would add vehicles 

to those movements that would represent a considerable contribution to the cumulative 

conditions and the project would have an adverse impact on these intersections. 

The Terminal/Extension Project would result in a substantial increase in vehicle trips to and from 

new developments, particularly in the area bounded by Mission, Folsom, First and Main Streets. 

Along First and Howard Streets there is a high volume of traffic destined to the I-80/Bay Bridge 

on-ramp at First/Harrison and to the U.S. 101 southbound on-ramp at Fourth/Harrison (via 

Howard and Fourth Streets) to which the Terminal/Extension Project would contribute additional 
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5-144 5.19 TRANSIT, TRAFFIC AND PARKING

vehicles and result in increased congestion. Similarly, the planned modifications to the I-80 

westbound off-ramp at Fremont Street would add a second leg that will provide access to Folsom 

Street and result in an increase in vehicles on Folsom Street. The combined increase in vehicles 

on Folsom Street due to the modified ramp and vehicle-trips generated by the 

Terminal/Extension Project would result in LOS E conditions at the intersection of The 

Embarcadero/Folsom Street. 

Mitigation: The Project would result in adverse impacts at seven intersections under both the 

baseline plus project and cumulative conditions. Improvements at individual intersections may 

reduce localized congestion somewhat, but may not mitigate operating conditions to less than 

adverse levels. As a result of the constraints at downstream intersections and the I-80/U.S. 101 

on-ramps and mainline, mitigation measures for the seven intersections have not been proposed, 

and the impacts associated with the Project would be considered adverse and unmitigable. 

To help improve 2020 Cumulative operating conditions, the San Francisco Department of 

Parking and Traffic (DPT) may request sponsors of development projects in the South of Market 

area to contribute to the new Integrated Transportation Management System (ITMS) program. 

This program is a citywide real-time electronic transportation management system that would 

include the installation of various Intelligent Transportation System (ITS) infrastructure 

components to improve traffic circulation within the City. The program would monitor and 

manage traffic by receiving real-time information at a Traffic Management Center via closed 

circuit TV cameras. The South of Market area has been identified as the area within which the 

first phase of the system would be implemented. 

The implementation of the ITMS program would improve overall traffic conditions and reduce 

traffic congestion in the City. Although the implementation of ITMS may not directly mitigate 

the adverse impacts of the Project under 2020 Terminal/Extension Project conditions or 2020 

Cumulative conditions, this program would result in overall traffic improvements and lessening 

of congestion, and would facilitate traffic circulation in the South of Market area. 

5.19.4.4 Traffic Impacts Associated with Draft Transbay Redevelopment Project Area 

Design for Development Vision 

To account for the increased demand for pedestrian and bicycle facilities with the new Transbay 

Terminal and the new development throughout the Transbay Area, the San Francisco 

Redevelopment Agency has developed a Draft Transbay Redevelopment Project Area Design for 

Development Vision (August 2003) that includes proposed sidewalk widenings with 

corresponding reduction in the adjoining street widths (as described in Section 2.2.4.2 of the 

Final EIS/EIR). This section reviews the traffic impacts associated with the sidewalk widening 

proposals. 

To accomplish this review, the results of the traffic analysis described in the previous section 

were reevaluated for the 2020 Cumulative conditions. For each of the analysis intersections, the 

weekday P.M. peak hour intersection operating conditions were examined to see if it would be 

possible to reduce the number of travel lanes and still maintain acceptable operating conditions 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-145 

(i.e., LOS D or better). In addition, the actual configuration of the streets was investigated to 

identify locations where: (A), lane imbalances were present (i.e., a street with two lanes on one 

side of an intersection and three lanes on the other side); (B), perpendicular/diagonal parking 

could be converted to parallel parking; or (C), turn lanes could be converted into turn pockets. 

Although these changes would not result in the complete elimination of travel lanes, they would 

allow for wider sidewalks to be created for portions of the streets. As part of this analysis, no 

changes were proposed or evaluated at intersections that were projected to operate with 

unacceptable conditions (i.e., LOS E or F) during the weekday P.M. peak hour. 

For the major vehicular corridors in the study area (such as Folsom, Howard, Fremont, First 

and Essex Streets), the potential to establish peak-period tow-away lanes was assessed. Since 

these streets accommodate substantial traffic during the morning and evening commute periods, 

it may be possible to eliminate travel lanes during off-peak times. As a result, the current 

capacity would be maintained during the weekday P.M. peak hour, and would not change the 

intersection operating conditions, but additional sidewalk space could be created. 

In addition, the potential to extend westbound Folsom Street was assessed. Based on the 

projected weekday P.M. peak hour intersection operating conditions, it would be possible to 

extend westbound Folsom Street for two blocks (from Main Street to Fremont Street) and 

maintain acceptable intersection operating conditions. 

Following are changes that could be made to the street network within the Transbay Area that 

are not anticipated to introduce new adverse traffic impacts. 

Spear Street has two lanes southbound between Market Street and Howard Street. South of 

Howard Street, it widens to three lanes and continues as three lanes until Harrison Street. It 

would be possible eliminate a travel lane between Howard Street and Harrison Street, as long as 

three lanes are provided at the intersection with Harrison Street. The southbound left-turn 

pocket at the intersection of Spear/Harrison would need to be about 150 feet long. 

North of Folsom Street, Main Street has three northbound lanes. It would be possible to narrow 

Main Street to two lanes at the north side of the intersection with Folsom Street, as long as three 

lanes were maintained at the intersection with Howard Street. The northbound left-turn pocket 

at the intersection of Main/Howard would need to be about 175 feet long. 

Between Mission Street and Folsom Street, Beale Street has three southbound lanes. These 

lanes need to be maintained. 

During the peak morning and evening commute periods, the current configuration of Fremont 

and First Streets would need to be maintained. During the off-peak hours, it would be possible 

to reduce the number of travel lanes on each street. As a result, peak period tow-away lanes 

could be established on one side of the street. A peak-period tow-away lane on Fremont Street 

was found not to be feasible due to the configuration of the street and the various lane 

requirements. 
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5-146 5.19 TRANSIT, TRAFFIC AND PARKING

Between Harrison and Folsom Streets, Essex Street has two northbound and two southbound 

lanes. It would be possible to eliminate one northbound lane. In addition, it would be possible 

to establish a peak period tow-away lane in the southbound direction. 

Between Main Street and The Embarcadero, Folsom Street has three eastbound lanes and one 

westbound lane. To the west of Main Street, Folsom Street has four eastbound lanes. Between 

Fremont Street and Main Street, it would be possible to eliminate one eastbound lane and 

establish a new westbound lane (an extension of the current two-way street for an additional two 

blocks). It should be noted that the infrastructure for this conversion to two-way traffic would be 

associated with the temporary terminal project. 

Howard Street has two lanes between Fremont Street and The Embarcadero in the eastbound 

direction. For this entire length, only one eastbound lane would be necessary, except at the 

intersection with Main Street. At this location, an eastbound left-turn pocket would need to be 

provided. 

5.19.5 IMPACTS ON PARKING

A portion of the existing public and private parking facilities (parking lots) in or near the existing 

Transbay Terminal would be eliminated as a result of the Full Build Alternative. Approximately 

1,950 (14 percent of study area parking) off-street parking spaces would be eliminated, including 

260 spaces within the current Transbay Terminal building. Although the Full Build Alternative 

would eliminate off-street parking, new land use in the Transbay Terminal Redevelopment Area 

would have its own parking facilities. 

With the loss of parking, vehicles previously bound for the displaced parking spaces would have 

to park in other parking facilities nearby or the people making these trips may now chose to use 

transit, given the reduced availability of parking, and enhanced accessibility of transit services.

Based on a review of a recent parking inventory, the current study area parking supply is at 

approximately 85 percent capacity during the weekday-midday. As a result of the reduction in 

parking spaces, usage is likely to reach capacity during the weekday midday. Given the first-in 

first-served nature of parking, with early morning commuters able to park closer to their 

destination, loss of area parking would mean that vehicles arriving later would have to park 

farther away from their destinations or chose another mode of transportation. The permanent 

loss of parking could deter commuters from driving, with a probable increase in public transit 

use. The provision of a new multi-modal transit facility that provides improved access to 

locations throughout the region would serve to mitigate the adverse parking capacity impacts. 

The displacement of parking spaces is not generally considered a physical environmental effect 

but is a social effect and an inconvenience to those who must seek other parking. The 

displacement of parking spaces and any resulting parking deficits are also not considered to be a 

permanent condition as drivers my be induced to seek and find alternative parking facilities and 

shift to other modes of travel. 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-147 

5.19.6 NON-MOTORIZED TRAFFIC IMPACTS

This section reviews the long-term effects of Terminal/Extension Project on pedestrian and 

bicycle conditions in the area surrounding the Transbay Terminal. It should be noted that the 

following analysis did not take into account the proposed sidewalk widenings contained in the 

Draft Transbay Redevelopment Project Area Design for Development Vision released by the 

San Francisco Redevelopment Agency in August 2003. Implementation of any or all of the 

proposed sidewalk widenings would result in improved pedestrian capacity and flows in the 

area. Thus, the following analysis reports “worst-case” conditions. 

5.19.6.1 Pedestrian Impacts 

Impacts on pedestrians were evaluated by modeling peak period walk trips with and without the 

Terminal/Extension Project and calculating pedestrian level of service at five intersections in the 

vicinity of the proposed new Transbay Terminal, which is the main area of pedestrian activity 

associated with the project. 

Baseline surveys of existing pedestrian volumes were made in spring 2001 and future (2020) 

volumes projected based upon the level of transit and retail/commercial/other activity anticipated 

in the area. Two project alternatives were considered (1) no pedestrian tunnel between the 

terminal and Market Street and (2) a direct underground pedestrian tunnel connecting the 

Caltrain platform or mezzanine area with the BART/Muni mezzanine under Market Street. 

The model is the San Francisco Transportation Authority travel model, modified to include 

assignment of future walk trips generated by increased transit access and higher land use 

densities from redevelopment. The study area was divided into various analysis zones, as shown 

in Figure 5.19-1. The modified model predicts pedestrian trips among the analysis zones that 

have the potential to generate pedestrian traffic and assigns them to certain pathways along city 

streets and through intersections. The baseline surveys provide a measure for calibrating 

estimated future pedestrian volumes and movements to ensure they are reasonable. 

Projected pedestrian volumes moving through a crosswalk translate to an estimate of the surface 

square footage available to each pedestrian and expected pedestrian flow rates (pedestrians per 

minute per foot). Level of service (LOS) is based upon the estimated space per pedestrian and a 

corresponding flow rate during the peak 15 minutes of pedestrian activity. Levels of service 

criteria are drawn from the Highway Capacity Manual (Transportation Research Board, 

Chapter 13). Similar to traffic, a pedestrian volume-to-walkway capacity relationship can be 

derived. A pedestrian volume to walkway capacity ratio of 0.40 to 0.28 equates to LOS C, for 

instance; a V/C ratio of 1.00 or higher equates to LOS F. The corresponding square footage per 

pedestrian under LOS F is 6 or less, and the average pedestrian flow rate is 25 or more 

pedestrians per minute per foot. 
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5-148 5.19 TRANSIT, TRAFFIC AND PARKING

Figure 5.19-1: Aggregated TAZ Used for Pedestrian / Bicycle Analysis 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-149 

The five study area intersections where crosswalk LOS was evaluated are: 

• Mission and First Streets 

• Mission and Fremont Streets 

• Howard and First Streets 

• Howard and Fremont Streets 

• Folsom and Beale Streets 

Important parameters affecting pedestrian volumes in the study area are such items as the access 

mode splits for Caltrain, AC Transit and other transit riders, peak hour mode shares, increased 

street activity from redevelopment. Several important assumptions for the 2020 P.M. peak hour 

pedestrian forecasts are: 

• 80 percent walk access for Caltrain riders commuting to San Francisco39

• 50 percent walk access for Caltrain riders reverse commuting to points south40

• 83 percent walk access for AC Transit riders41

• Substantial increases in background pedestrian traffic due to both continuing growth in 

the area and growth due to redevelopment. 

2020 Pedestrian Volumes and LOS, Background Plus Project (Total Traffic). As a result of 

continuing growth in the study area and as a result of the proposed project improvements, 

pedestrian trips are projected to increase 59.5 percent between 2000 and 2020 in the analysis 

zones surrounding the Transbay Terminal. At the five individual study area intersections, where 

pedestrian activity or growth in activity would be concentrated, the percentage increases in 

pedestrian traffic during the P.M. peak hour would be substantially greater, from 300 percent to 

over 2000 percent, depending upon location. 

All pedestrians are assumed to use surface streets to move among analysis zones, including 

through the five study area intersections evaluated. The total pedestrian counts for 2001 and the 

projected volumes under the background plus project scenario for 2020 are shown in 

Table 5.19-5. The volumes are for the 15-minute p.m. peak window of highest pedestrian 

activity. 

 

39 Source: Nelson\Nygaard Consulting: Based on existing mode split at the Fourth and Townsend Station (Source Parsons 

Transportation Group) and existing mode split at the Transbay Terminal (Source: May 2001 Transbay Terminal Patron Survey 

conducted by Nelson\Nygaard). Assumes that once Caltrain is extended to the Transbay Terminal, the walk split would increase 

from the existing condition at Fourth and Townsend to almost equal to that of AC Transit Transbay Terminal Patrons. 

40 Source: Based on the existing Caltrain mode splits at Fourth and Townsend Station and the assumption that the walk mode in 

the reverse commute direction would increase substantially if the Terminal station were moved. 

41 Source: Nelson\Nygaard Consulting, Transbay Terminal Spring 2001 patron survey. 
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5-150 5.19 TRANSIT, TRAFFIC AND PARKING

Table 5.19-5: Pedestrian per Intersection: 2001 and 2020 Baseline Plus Project 

(15-minute P.M. Peak Total Pedestrian Traffic) 

Intersection May 2001 

Pedestrians 

% Increase 

by 2020 

Increase Due to 

Area Growth & 

Redevelopment 

Increase Due 

to AC/Caltrain 

2020 Total 

Peds/Intersection1

Mission & First 895 915% 8,185 454 9,534 

Mission & Fremont 854 380% 3,247 141 4,243 

Howard & First 228 2182% 4,967 294 5,489 

Howard & Fremont 235 1765% 4,141 70 4,446 

Folsom & Beale 117 839% 982 12 1,111 

 1 Existing plus increase due to area growth and redevelopment and increase due to AC/Caltrain. 

The percentage increases in pedestrian volumes due to area growth and redevelopment are high 

because they represent the change over a 20-year period. Pedestrian volumes in the area are 

anticipated to increase markedly with or without the proposed project and additional 

redevelopment efforts. In addition, the current pedestrian volumes upon which the percentage 

change is based are quite small in many cases. 

Intersection LOS. When a pedestrian arrives at a particular intersection, he or she may use a 

variety of combinations and crosswalks to move through the intersection. For example, at the 

first study intersection, Mission and First Streets, the May 2001 field survey showed that 895 

pedestrians made 1,945 “movements” through the intersection. A movement is considered 

entering or exiting a crosswalk or turning the corner. 

Pedestrian LOS accounts for all movements that pedestrians make through an intersection. 

Figure 5.19-2 shows pedestrian LOS associated with the pedestrian volumes and LOS 

summarized in Table 5.19-6. As shown, pedestrian LOS is projected to be poor, varying from 

LOS E to F, at four of the five intersections evaluated by 2020, with continuing growth in the 

area and as a result of project generated pedestrian activity. 

Changes to Pedestrian LOS Due to Project Impacts Only. Not all of the increase in 

pedestrian activity listed in Table 5.19-6 is attributable to the Transbay Terminal/Caltrain 

Downtown Extension Project, including area redevelopment. A considerable increase in 

pedestrian movements results from area growth between 2001 and 2020. 

According to output from the SFTA model, about seven percent of the increase in total 

pedestrian volumes by 2020 actually would be generated by the project (9,482 of 140,845 

pedestrian trips among the traffic analysis zones analyzed). Following a similar methodology as 

that used to estimate total pedestrian trips from all sources, the impacts of just the project were 

estimated. Intersection pedestrian LOS was recalculated by adding Caltrain, AC Transit, and 

redevelopment-generated pedestrian trips to the 2001 activity level 
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5.19 TRANSIT, TRAFFIC AND PARKING 5-151 

Figure 5.19-2: Corner and Crosswalk Pedestrian Level of Service 

(2020 Baseline and Project)
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5-152 5.19 TRANSIT, TRAFFIC AND PARKING

Table 5.19-6: Pedestrian LOS: P.M. Peak Conditions (Peak 15-minutes) 

2020 Baseline Plus Project 

Intersection Crosswalk 

Ped Space 

(sq ft/ped) LOS Surge LOS Corner Ped Space (sq ft/ped) LOS 

North 6 E F NW -1.5 F 

East 12 E E NE -1.2 F 

South 18 D E SW 4.4 F Mission & First 

West 14 E E SE 7.9 E 

North 22 D D NW 6.6 E 

East 34 C D NE 8.7 E 

South 15 D E SW 42 B 

Mission & 

Fremont 

West 25 C D SE 8.9 E 

North 16 D E NW .47 F 

East 13 E E NE 4.3 F 

South 37 C C SW -0.16 F Howard & First 

West 13 E E SE 3.3 F 

North 6 E F NW -2.1 F 

East 16 D E NE -2.7 F 

South 43 B C SW 2.6 F 

Howard & 

Fremont 

West 18 D E SE 4.4 F 

North 73 B B NW 18 D 

East 114 B B NE 18 D 

South 49 B B SW 15 D Folsom & Beale 

West 53 B B SE 19 D 

1

 Level of service (LOS) standards from Highway Capacity Manual (Chapter 13) 

Design Option 1: No Pedestrian Tunnel between Transbay Terminal and Market Street. 

Under this design option, all pedestrians would use surface streets to move among analysis 

zones, including through the five study area intersections evaluated. The pedestrian volumes that 

would be generated by just the project, in 2020, are shown Table 5.19-7. The volumes are for 

the 15-minute p.m. peak window of highest pedestrian activity. 

Table 5.19-7: 2020 Project Only Impacts: Increase in Pedestrian in Study Intersections 

(During 15-minute P.M. Peak -- No Pedestrian Tunnel)

 Intersection May 2001 

Peds 

% Increase 

Due to Project

Increase Due to 

Redevelopment

Increase Due to 

AC & Caltrain 

2020 Project 

Peds/Intersection 

 Mission & First 895 118% 1,059 454 2,408 

 Mission & Fremont 854 74% 633 141 1,628 

 Howard & First 228 293% 666 294 1,188 

 Howard & Fremont 235 282% 662 70 967 

 Folsom & Beale 117 143% 168 12 297 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.19 TRANSIT, TRAFFIC AND PARKING 5-153 

The total number of pedestrians at each intersection in 2020 was assigned to the crosswalks and 

corners in proportion to existing travel patterns. Intersection LOS was calculated, as shown in 

Table 5.19-8 and illustrated in Figure 5.19-3. 

Table 5.19-8: Pedestrian LOS: P.M. Peak Conditions (Peak 15-minutes) 

2020 Project Only -- No Pedestrian Tunnel 

Intersection Cross-walk Ped Space (sq ft/ped) LOS Surge 

LOS Corner Ped Space (sq ft/ped) LOS 

North 24 C D NW 12 E 

East 47 B C NE 9 E 

South 72 B B SW 34 C Mission & First 

West 55 B C SE 36 C 

North 57 B B NW 24 C 

East 90 B B NE 30 C 

South1 39 C C SW 112 B Mission & Fremont 

West 66 B B SE 31 C 

North 75 B B NW 19 D 

East 61 B C NE 34 C 

South 171 A B SW 16 D Howard & First 

West 45 B C SE 27 C 

North 28 C D NW 14 E 

East 75 B B NE 17 D 

South 196 A A SW 50 B Howard & Fremont 

West 85 B B SE 31 C 

North 271 A A NW 81 B 

East 426 A A NE 81 B 

South 194 A A SW 62 B Folsom & Beale 

West 200 A A SE 86 B 1 Under the Pedestrian Tunnel Design Option, LOS at this crosswalk would improve to LOS B. Otherwise, intersection 

pedestrian LOS is not anticipated to change with a pedestrian tunnel in place.

Design Option 2: Underground Pedestrian Tunnel to Market Street. The terminal and 

extension design alternatives allow for an optional pedestrian connection between the terminal 

and Muni Metro and BART, which are located one block away on Market Street. If an 

underground pedestrian connection to BART were included in the project, some of the peak 

period pedestrian trips in Figure 5.19-3 would be diverted from the intersections shown in that 

figure. This following analysis looks at the impact of the underground tunnel on pedestrian LOS 

in the peak 15-minute period at the intersection of Fremont and Mission Streets. 

Assuming that many transit users of the Transbay Terminal would find the pedestrian connection 

underneath Fremont Street convenient just to cross Market Street away from traffic and weather, 

Table 5.19-9 illustrates with high and low estimates what the numbers of users might be. Those 

connecting to BART and Muni would make up about one-third of the total low case, or about 

2,400 daily users. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-154 5.19 TRANSIT, TRAFFIC AND PARKING

Figure 5.19-3: Corner & Crosswalk Pedestrian Level of Service (LOS) 2020 Project 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.19 TRANSIT, TRAFFIC AND PARKING 5-155 

Table 5.19-9: Potential Daily Users of the Proposed Fremont Street 

Pedestrian Tunnel 

Case High-Speed Rail Caltrain AC Transit Total 

Low Estimate 2,300 3,400 2,400 8,100 

High Estimate 4,700 6,800 5,400 16,900 

Note: Assumes range of 10% (low) to 25% (high) of transit passengers using the tunnel to cross Market Street in 

addition to those connecting with BART or Muni Metro. 

Source: Parsons Corporation, September 2003.

• Pedestrian Travel Due to Redevelopment. 

Pedestrians traveling between analysis zones immediately surrounding the terminal were not 

anticipated to travel underground for one block of their journey. A small amount of pedestrian 

traffic generated by redevelopment in the Transbay Terminal area might, however, use the 

underground connection to grain access to BART or Muni Metro. The propensity for these 

people to use the underground connection is limited since either their origin or destination would 

be above ground. As a result, in the peak 15-minute period, only one pedestrian trip is expected 

to be diverted from the Fremont & Mission intersection.42 

• Pedestrian Travel Due to Increased AC Transit Ridership. 

AC Transit riders traveling between the Transbay Terminal and analysis zones to the north of 

Market Street could use the underground connection, but the propensity for these people to use 

the connection is limited since AC Transit buses arrive above ground and destinations are also 

above ground. For AC Transit riders transferring to BART and Muni Metro, however, it is 

assumed that 50 percent would use the underground connection.

43 The combined impact of 

transfers and those using the underground passageway to walk between AC Transit and areas 

north of Market Street is estimated to divert 52 pedestrian trips from the Fremont & Mission 

intersection during the 15-minute peak period.44 The May 2001 Terminal Patron Survey showed 

that, of the 1,078 AC Transit patrons surveyed, 11 patrons (one percent) transferred between 

AC Transit and BART, and 42 (about four percent) transferred between AC Transit and Muni 

Metro. 

 

42 SFTA model projections for 2020 Baseline + Project conditions = 472 peak period pedestrian trips between the Transbay 

Terminal and north of Market Street. Assuming 25% travel through Fremont & Mission, and 10% use underground connection = 

1 trip. 

43 Because AC Transit riders would enter the terminal above ground, it is assumed that one-half would make the connection on 

surface streets and one-half would use the tunnel. 

44 AC Transit projections show 5,469 peak hour AC Transit riders in 2020. Assuming 83% access the terminal as pedestrians = 

1,531 ped trips in the peak 15-minute period. The SFTA model predicts 44.5% of pedestrians traveling from/to the terminal will

be from/going to north of Market Street = 566 pedestrians. Assuming 25% walk through Fremont & Mission and 10% use the 

underground connection = 14 pedestrian trips. 1% of the peak 15-minute AC Transit trips are estimated to transfer to BART. 

Assuming 50% use underground walkway = 7 ped trips. 4% of the peak 15-minute AC Transit trips are estimated to transfer to 

BART. Assuming 50% use underground walkway = 31 ped trips. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-156 5.19 TRANSIT, TRAFFIC AND PARKING

• Pedestrian Travel Due to Caltrain Ridership 

Those traveling between the train level at the Transbay Terminal and analysis zones to the north 

of Market Street might use the underground connection, given that the passageway would be on 

the same level as the Caltrain mezzanine. In addition, it is expected that two percent of Caltrain 

riders would transfer between Caltrain and BART in downtown San Francisco and that all 

transferring riders would use the underground connection. It is also expected that three percent 

of Caltrain riders would transfer between Caltrain and Muni Metro in downtown San Francisco 

and that all transferring riders would use the underground passageway. The combined impact of 

transfers and those walking between Caltrain and areas north is estimated to divert 55 

pedestrian trips from the Fremont & Mission intersection during the 15-minute peak period.45

A total of 108 pedestrian trips are expected to be diverted from the Fremont and Mission Streets 

intersection during the 15-minute peak period. The pedestrian LOS impacts would not change at 

this intersection under any future scenario except for 2020 Project Only Impacts. The south 

crosswalk would improve from LOS C to LOS B. 

• Other Pedestrian Conditions 

Under the West Ramp Alternative, a street-level bus boarding area would be located between 

Fremont and Beale Streets. Muni bus lines 2/3, 5, 6/7, 38 and 38L and Golden Gate Transit 

basic bus service lines 20, 30, 50, 80 and 90 would use the street-level boarding area. The Muni 

buses listed currently board and alight on the “hump” area in front of the terminal, while the 

Golden Gate Transit lines currently board along Mission and Fremont Streets. As a result of the 

project, more pedestrians would have to cross Fremont Street to reach the street-level bus 

boarding area. About 100 buses would pull out of this area between approximately 5:00 p.m. 

and 7:00 p.m. 

To facilitate transit access between the bus boarding area and Fremont Street, the 

Terminal/Extension Project designs include a new traffic signal on Fremont Street between 

Mission and Howard Streets. This signal would be located just south of the terminal and may 

also include a full stop phase to facilitate pedestrian flows crossing Fremont Street. 

Pedestrian Mitigation Measures. Under the 2020 Baseline plus Terminal/Extension Project 

condition, eleven corners and two crosswalks fall to pedestrian Level of Service F. Isolating the 

Project Only impacts from the 2020 Baseline plus Project condition indicates that the project 

itself does not cause the level F conditions. The lowest pedestrian levels of service associated 

with the project occur at First and Mission Streets where two corners fall to LOS E, and at 

Howard and Fremont Streets where one corner falls to LOS E. 

 

45 548 15-minute peak Caltrain-generated pedestrian trips. If 44.5% travel from the terminal to north of Market Street and 25% 

of those walk through the Fremont & Mission intersection, and if 25% of those use underground tunnel, this equals 15 ped trips.

There are 785 predicted peak 15-minute total Caltrain trips. Of these, 2% (16 trips) are expected to transfer to/from BART and

3% (24 trips) are expected to transfer to/from Muni, all of which would use the underground connection. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.19 TRANSIT, TRAFFIC AND PARKING 5-157 

Pedestrian mitigation measures that can be considered include: 

• Preventing narrowing of sidewalks through future construction; 

• Using future construction or redevelopment as opportunities to increase building setbacks thereby increasing sidewalk widths. Particular areas where such widening is most 

needed include: 

o The southeast corner of Fremont and Missions Streets, 

o The northeast corner of First and Missions Streets, 

o The north side of Mission Street between First and Fremont, and 

o Sidewalks south of Howard Street along Folsom, First, Fremont, and Beale that 

are less than 10 feet wide; 

• Ensuring that Transbay Terminal design increases corner and sidewalk widths at the four 

intersections immediately surrounding the Transbay Terminal; 

• Eliminating or reducing sidewalk street furniture on corners, such as newspaper boxes 

and magazine racks. For example, sidewalk furniture on the four corners of Mission and 

First currently reduces effective corner space, blocks pedestrian movements, and/or 

exacerbates space issues associated with bus queuing; 

• Re-timing traffic light signalization. This could improve pedestrian levels of service at 

each of the intersections studies that fall into LOS F; 

• Providing cross-walk count-down signals. This would be most valuable at the 

intersections and cross-walks immediately surrounding the terminal, especially since 

pedestrians are more likely to dash on a flashing hand when trying to catch a bus or train; 

• Providing lights within crosswalks to warn when pedestrians are present in the crosswalk, 

such as at the cross-walk associated with the mid-block bus loading area, and 

• Providing crosswalk signalization at intersections where they do not exist already, such 

as Folsom and Beale Streets. 

5.19.6.2 Bicycle Impacts 

Bicycle traffic growth with and without the project was estimated by comparing existing bicycle 

volumes, obtained from field surveys, with estimated volumes for the 2020 Baseline plus the 

Transbay Terminal/Caltrain Downtown Extension Project condition and the 2020 Project 

condition. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-158 5.20 CONSTRUCTION STAGING AND METHODS

While there is no standard for determining bicycle levels of service, the increase in bicycle traffic 

was estimated between existing conditions, the 2020 Baseline plus Project, and the 2020 Project 

Only conditions. The estimate was based on the San Francisco County Transportation 

Authority’s transportation model outputs showing bicycle traffic between the analysis zones, 

assuming full Transbay Terminal Project build-out and redevelopment. The bicycles added to 

the street due to increased AC Transit ridership and Caltrain ridership were also estimated. 

The estimates show that peak bicycle traffic at the five study intersections could increase 

substantially over the next twenty years. It was estimated that up to 425 bicycle trips could 

travel through the five study intersections in the 15-minute peak window under the 2020 

Baseline plus Project condition and 290 under the 2020 Project condition compared to a total of 

45 counted in the Spring of 2001. It should be noted, however, that there is no standard for 

determining bicycle level of service. 

Some Caltrain riders are projected to ride bicycles between Caltrain and their ultimate 

destinations. It is estimated that the new terminal will attract about 6,800 primary-direction, 

peak period commuters (traveling inbound to the Transbay Terminal in the a.m.) and about 

3,125 reverse-direction, peak-period commuters (traveling outbound from the Transbay 

Terminal in the a.m.). 

Existing data on bike usage of Caltrain passengers at the Fourth and Townsend Station indicates 

that approximately 5 percent of primary-direction, peak period commuters and 15 percent of 

reverse-direction, peak period commuters use a bicycle as part of their total commute trip. 

Assuming these same proportions of bike trips to and from the new Transbay Terminal, it is 

estimated that there will be 340 primary-direction bike/Caltrain commuters and 469 reversedirection bike/Caltrain commuters. However, not all of these commuters will require bike 

parking at the Transbay Terminal. Assuming that 20% of the primary-direction commuters and 

35% of the reverse direction commuters require bike parking, a total of 232 bicycle storage 

spaces would be needed. 

The San Francisco Department of Parking and Traffic is considering an extension of the Howard 

Street bike lane (that currently runs between Fifth and Eleventh streets) to Fremont Street and 

the provision of a new bike lane on Second Street. The addition of these lanes would improve the 

quality and comfort of bicycling in the area around the Transbay Terminal. 

5.20 CONSTRUCTION STAGING AND METHODS 

Project construction activities that would occur with the Transbay Terminal/Caltrain Downtown 

Extension/Redevelopment Project would not occur for the No-Project Alternative. Even though 

project construction activity would be relatively short-term and geographically limited, potential 

construction impacts were an important factor in the selection of the proposed alternatives 

considered in this DEIS/DEIR. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-159 

For example, the Tunneling Option for the Caltrain Extension was evaluated in part due to its 

reduced impacts on adjoining land uses during construction. Tunneling in lieu of cut-and-cover 

could be used for that portion of the alignment with underlying rock geologic formations. These 

formations occur along the alignment from approximately Station 51+00 (Townsend and Third 

Streets) to Station 81+00 (Second and Folsom Streets). 

Since construction impacts of the project are of concern to the community, this section describes 

the proposed construction process and methods. Section 5.21 describes potential impacts and 

mitigation measures for construction. 

This section divides the construction process into several steps based upon the type of 

construction and when it would occur. Section 5.20.1 summarizes preconstruction activities. 

Section 5.20.2 summarizes construction activities. 

5.20.1 PRE-CONSTRUCTION ACTIVITIES

A summary of preconstruction activities is provided in Table 5.20-1 and discussed individually 

in the following. 

Table 5.20-1: Pre-construction Activities -- Caltrain Extension 

• Undertake Detailed Geotechnical Investigation 

• Prepare Final Design and Construction Contracts 

• Prepare Vehicular and Pedestrian Traffic Control/Detour Plans 

• Undertake Building Data Survey 

• Undertake Pre-Construction Business Survey 

• Establish Construction-Related Community Information / Outreach Program 

• Acquire Property and Easements: 

o Easements involve specific parcels along: Seventh, Townsend, Stanford, Second, Colin P. Kelly, 

Brannan, DeBoom, Federal Way, Bryant, Tehama, Howard, and Natoma 

o Full acquisitions include properties along Brannan, Howard, Natoma, Minna, Tehama, Beale, and 

the existing Transbay Terminal Site

Preliminary Engineering, Development of Construction Contracts, and Final Design. 

During preliminary engineering and final design, detailed design elements of the Transbay 

Terminal and Caltrain Downtown Extension would be developed, reflecting, among other 

subjects, final geotechnical investigations. Construction contract packaging will be determined 

as part of the Preliminary Engineering activities. As part of the final design, the TJPA and the 

JPB would work with property owners planning to build new structures adjacent to the proposed 

Project components to integrate construction of the Caltrain project with construction of the 

private structures to reduce Project construction impacts. 

Vehicular and Pedestrian Traffic Plans. Construction of the Project would temporarily 

interfere with the normal flow of traffic, causing some lanes and streets to be closed to vehicles 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-160 5.20 CONSTRUCTION STAGING AND METHODS

for various durations. Some streets would be subject to lane and temporary closures as 

summarized in Table 5.20-2. During final design, street traffic control plans would be developed 

in cooperation with Caltrans, the City/County of San Francisco (DPT, police and fire 

departments, and Muni) to accommodate required pedestrian and traffic movements. To the 

extent practical, traffic lanes would be maintained in the appropriate directions, particularly 

during peak traffic hours. 

Table 5.20-2: Street Closures During Construction

Townsend Street (Fifth to Clarence Place). Cut-and-cover construction would be progressed on a block by 

block basis, so approximately one block would be affected at a time. There would be no on-street parking 

during construction of a particular block. A limited number of complete closures to all traffic would occur 

during cut-and-cover construction until a temporary street deck is placed over the subway construction. A 

limited number of complete closures are also required for removal of the deck and reconstruction of the 

roadway. Cross street traffic would also be subject to limited closures. Eight business driveways would be 

affected by the closures. 

If tunneling construction is chosen for a portion of the alignment it would begin on Townsend Street just 

east of Third Street. The temporary decking installed for the cut-and-cover construction in the area of the 

beginning of the tunnel would remain in place until tunneling was completed. A limited number of 

complete closures would then be required for removal of the decking and pavement reconstruction. 

Clarence Place (Between Townsend and Brannan) For both cut-and-cover and tunneling construction 

alternatives the south end of this block would be completely closed for limited times while construction on 

Townsend Street, east of Third Street, occurs. 

Stanford Street (Between Townsend and Brannan) For the cut-and-cover construction alternative, the south 

end of this block would be completely closed during construction of the line segment for this block. During 

construction, access from Brannan would remain available. 

This street would not be affected by the tunneling alternative. 

Second Street (Brannan to Howard). For the Cut-and-Cover Option, construction would be progressed on an 

approximate block-by-block basis, so approximately one block would be affected at a time. There would be 

no on-street parking during construction. A limited number of complete closures to all traffic would occur 

during cut-and-cover construction until a temporary street deck is placed over the subway construction. A 

limited number of complete closures would also be required for removal of deck and reconstruction of the 

roadway. Cross street traffic would also be subject to limited closures. Eight (8) business driveways and 

three (3) residential driveways would be affected. Temporary alternative access would be required to 

maintain access to dead end streets at De Boom, Federal, Dow Place, and Tehama. Temporary access 

would be provided through easements across through private property such as parking lots. 

 For the Tunneling Option, there would be very limited impacts to streets. It is anticipated that tunneling 

would progress from two locations in this segment, midway between Brannan and Bryant, and just south of 

Folsom. At these locations vertical shafts will be constructed and temporary decking installed. A limited 

number of complete closures would be required during construction of the vertical shafts and placement of 

temporary decking. A limited amount of on-street parking will be lost during tunneling operations. Traffic 

would be maintained throughout tunnel construction. A limited number of complete closures would be 

required for removal of the temporary decks and pavement reconstruction. 

Natoma Street (Between First and Second) During construction of the Transbay Terminal this street would be 

subject to temporary closure for this portion of its alignment. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-161 

Table 5.20-2: Street Closures During Construction

First Street (Between Howard and Mission) During construction of the Transbay Terminal this street would 

be subject to limited closures while temporary bridging was installed to allow for subterranean construction 

under the road.

Minna Street (Between First and Second) During construction of the Transbay Terminal this street would be 

subject to temporary closure for this portion of its alignment.

Fremont Street (Between Howard and Mission) During construction of the Transbay Terminal this street 

would be subject to limited closures while temporary bridging was installed to allow for subterranean 

construction under the road.

Beale Street (Between Howard and Mission) During construction of the Transbay Terminal the street would 

be subject to limited closures while temporary bridging was installed to allow for subterranean construction 

under the road.

Main Street (From Just South of Bryant to Howard) Construction would be progressed on an approximate 

block-by-block basis, so approximately one block would be affected at a time. There would be no on-street 

parking during construction of each block. A limited number of complete closures to all traffic would occur 

during cut-and-cover construction until a temporary street deck is placed over the subway construction. A 

limited number of complete closures would also be required for removal of the temporary deck and 

reconstruction of the roadway. Cross street traffic would also be subject to limited closures. Eight (8) 

business driveways would be affected by the closures. 

Mission Street (Beale to The Embarcadero) Construction would be progressed block by block, so 

approximately only one block would be affected at a time. There would be no on-street parking during 

construction of each block. A limited number of complete closures to all traffic would occur during cutand-cover construction until a temporary street deck is placed over the subway construction. A limited 

number of complete closures would also be required for removal of the deck and reconstruction of the 

roadway. Cross street traffic would also be subject to limited closures. Four (4) business driveways would 

be affected by the closures. 

First, Fremont and Beale Streets (Between Howard and Folsom) Temporary night time closures would be 

required for construction of the temporary and permanent access ramps to the permanent and temporary bus 

terminals. Some limited amount of on-street parking would be lost during construction activities.

Howard, Tehama, Clementina, Folsom and Harrison Streets (Between First and Second) Temporary night 

time closures would be required for construction of the permanent access ramps to the Transbay Terminal. 

Some limited amount of on-street parking would be lost during construction activities.

Essex (Between Folsom and Harrison) Some on-street parking would be temporarily eliminated during 

construction of the permanent access ramps to the Transbay Terminal.

Building Data Survey. A pre-construction structural survey would be completed to determine 

the integrity of existing buildings adjacent to and over the proposed extension. This survey 

would be used to finalize detailed construction techniques along the alignment and as the 

baseline for monitoring construction impacts during and following construction. During 

construction, the TJPA and JPB would monitor adjacent buildings for movement and, if 

movement is detected, take immediate action to control the movement. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-162 5.20 CONSTRUCTION STAGING AND METHODS

Detailed Geotechnical Investigation. During final design, additional sampling (drilling and 

core samples) and analyses of subsurface soil/rock conditions would be used to detail and 

finalize the excavation and its support system to be used in the retained cut, cut-and-cover and 

tunnel portions of the extension. Current data, including subsurface sampling conducted in 1995 

and 1996 for the 1997 Caltrain DEIS/DEIR have been used to identify the proposed construction 

techniques presented in the following sections, which form the basis for the impact analysis that 

follows in Section 5.21. 

Pre-Construction Business Survey. Prior to construction, the TJPA and JPB would contact and 

interview individual businesses along the alignment to gather information and develop an 

understanding of how these businesses carry out their work. This survey would identify business 

usage, delivery/shipping patterns, and critical times of the day or year for business activities. 

The survey would assist in: (a) the identification of possible techniques during construction to 

maintain critical business activities, (b) the analysis of alternative access routes for customers 

and deliveries to these businesses, (c) the development of traffic control and detour plans, and (d) 

the final determination of construction practices. 

Establishment of Construction Community Information/Outreach Program. A community 

construction coordination program would be established to provide on-going dialogue among the 

TJPA, the JPB and the affected community regarding construction impacts and possible 

mitigation/solutions. The program would include dedicated personnel, including an outreach 

office in the construction area, to deal with construction coordination. An important element of 

this program would be the dissemination of information in a timely manner regarding anticipated 

construction activities. 

Land and Easement Acquisition. Properties would need to be acquired prior to construction of 

the project. In addition, property easements would be obtained for those properties above the 

proposed tunnel portion. See Section 5.2 for a complete discussion of these acquisitions, 

including a review of relocation assistance that would be provided. 

5.20.2 CONSTRUCTION ACTIVITIES

Types, location, and lengths of construction activities that would occur for the Project are 

provided in Table 5.20-3 and are discussed below. 

Underground Utility Relocation. To the extent possible the Caltrain extension has been 

located to avoid conflicts with the space occupied by major utilities. In certain instances, the 

positioning of the alignment, station, and ancillary facilities would require that conflicting 

utilities be relocated. Relocation of utilities to a new permanent location so that they would not 

be affected by alignment or station construction would generally be performed prior to 

construction of the extension. Construction equipment typically required for utility relocation 

and restoration includes: excavator/backhoes, trenchers, trucks, cranes and 

generator/compressors. Cement trucks, pavers, rollers, and power compactors are typically 

required for street restoration. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-163 

Table 5.20-3: Construction Activities 

Construction 

Activities Location Length in Feet 

Relocate 

Utility Lines See Section 5.12 – Utilities Not 

Applicable 

Demolish Buildings 

As required along Townsend, Stanford, Second, Howard, and Streets. 

Also station platforms and maintenance buildings at current Caltrain 

San Francisco Station and Yard. 

Not 

Applicable 

Construct Temporary 

Bus Terminal and 

Access Ramps 

Needed to facilitate construction of the permanent Transbay Bus 

Terminal. 

See Chapter 2 of this EIS/EIR for location of proposed facilities. 

Not 

Applicable 

Construct New 

San Francisco Yard 

Support Tracks 

Within the existing JPB right of way between Common Street and 

16th Avenue. 1,550 

Construct New Fourth 

and Townsend Station 

Tracks, Platforms and 

Ancillary Facilities

Within the existing JPB right of way and San Francisco Yard, from 

Seventh to Fourth Street. 3,000 

Construct RetainedCut Section In existing San Francisco Yard between Common and Fifth Streets 

along Seventh and Townsend Streets. 1,850 

Cut-and-Cover Option – Both Alternatives: Along Townsend 

Street from between Fifth and Fourth Streets up to Second Street. 

Along Second Street to Howard Street. From Howard Street into the 

Transbay Terminal. 

3,550 

Second-to-Main Alternative: From Transbay Terminal along Main 

Street to just south of Harrison Street. 2,050 

Construct 

Cut-and-Cover 

Section and Ancillary 

Facilities 

Second-to-Mission Alternative: From Transbay Terminal along 

Mission St., ending just before The Embarcadero. 1,450 

Tunnel Option 

Construction of tunnel and ancillary facilities from Townsend Street 

starting just east of Third Street, crossing under Stanford Street and 

entering Second Street at Brannan Street, continuing up Second 

Street to Folsom Street. 

3,000 

Construct New 

Transbay Terminal, 

Ancillary Facilities, 

and Permanent Access 

Ramps 

See Chapter 2 of this EIS/EIR for description of the alternatives for 

the permanent Transbay Terminal and Access Ramps. 1,300 

Construct Permanent 

Offsite Bus Storage 

and Access Ramps 

Needed for permanent current Transbay Bus Terminal operations. 

See Chapter 2 of this EIS/EIR for a description of these permanent 

facilities. 

Not 

Applicable. 

San Francisco Yard to Transbay Terminal Corridor (Cut and 

Cover Option): Along Townsend St. from between Fifth and Fourth 

Streets up between Third and Second Streets. Along Second Street 

from Brannan St. to Howard St. A portion of Howard Street between 

Second and First Streets 

Reconstruct Streets 5,250 

Main St. Alignment Cut and Cover Option: From Transbay 

Terminal along Main Street from Howard to just south of Harrison 

St. 

1,450 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-164 5.20 CONSTRUCTION STAGING AND METHODS

Table 5.20-3: Construction Activities 

Construction 

Activities Location Length in 

Feet 

Mission Alignment Cut and Cover Option: From Transbay 

Terminal along Mission St., ending just before The Embarcadero. 1,300 

San Francisco Yard to Transbay Terminal Corridor Cut-andCover and Tunneling Options: Tunneling a portion of the 

alignment would reduce the amount of street reconstruction. 

Tunneling would start on Townsend Street just east of Third Street, 

then would go under the buildings located in the block at the corner 

of Townsend and Second Streets. The tunnel would then extend 

down Second Street to Folsom Street. 

3,180 

Utilities, such as high-pressure water mains and gas lines, that are not to be permanently 

relocated away from the work site, would be temporarily removed from the construction area. 

For these relocations, no or very brief disruption (less than a day) could occur to utility service. 

The utilities would be relocated temporarily at the early stages of construction and reset in 

essentially their original locations during the final backfilling above the construction. 

Utilities within the subsurface construction area that do not need to be relocated, either 

permanently or temporarily, would be uncovered during the early stages of excavation. These 

buried utilities, with the possible exception of sewers, are generally found within several feet of 

the street surface. They would be reinforced, if necessary, and supported during construction by 

hanging from support beams spanning across the excavation. 

If tunneling is used for a portion of the alignment, utility issues would be eliminated in those 

areas. 

Building Demolition. The Caltrain Downtown Extension alignment has been selected to 

minimize, to the extent possible, impacts on adjoining buildings and on the communities through 

which it passes. Still, for cut-and-cover construction methods, some properties would have to be 

acquired and the structures on these properties demolished. No building demolitions would be 

required in areas where the Tunneling Option is constructed. 

Equipment typically involved in demolition includes: crawler cranes, crawler dozer/loaders, 

pavement breakers, rubber-tired loader/bob cats, trucks, excavator/backhoes, generator/ 

compressors, and water trucks for dust control. 

Building Underpinning. Where the Tunneling Option is applied, existing buildings above the 

tunnel alignment would be underpinned. This underpinning would support the building in case 

of a partial tunnel collapse during construction. Equipment typically involved in underpinning 

includes: specialized pile drivers, air compressors, pneumatic tools such as jack hammers, front 

end loaders and dump trucks. 
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5.20 CONSTRUCTION STAGING AND METHODS 5-165 

Surface Rail Line and Station Construction. Both Caltrain Extension Alternatives would 

require removal and reconstruction of the existing yard tracks at the Fourth and Townsend 

Station including the removal and reconstruction of station platforms and the removal of existing 

maintenance buildings. Track removal and reconstruction would begin just north of Sixteenth 

Street and end at the existing station at Fourth Street. This work would provide the required 

track connections and yard space for the new mainlines crossing through the existing yard as 

they descend into the alignment proceeding down Townsend Street. This work would occur 

immediately after mobilization. 

Equipment used for removal of existing rail and platform and building improvements and 

construction of new track and station improvements include: crawler dozer/loaders, surface 

graders, rubber-tired loaders/bob cats, compactors, generators/compressors, rollers, small cranes, 

excavators/backhoes, trucks, concrete trucks, railroad track-laying equipment, welding machines, 

and water trucks for dust control 

Retained Cut Section. Prior to entering the subterranean subway section near Fifth Street, the 

new extension main track alignments would transition from surface to subsurface in a retained 

cut (depressed section) portion of the alignment (Station 12+50 to 31+00). This would occur in 

the existing San Francisco Yard between 7th Street (near Berry Street) and Townsend Street (near 

Fifth Street). Immediately adjacent to these main track alignments, in the area bounded by the 

corner of Seventh and Townsend Streets, is a fully depressed area that will accommodate yard 

tracks. This depressed yard area will also be part of a retained cut section. 

General Approach to Temporary and Permanent Structures. A temporary structural support 

system is required to retain the cut during excavation of material. After excavation this 

temporary system will be incorporated into the permanent retained cut structure. 

Temporary Structures and Excavation. This area of the project involves soft soils, including 

extensive deposits of soft Bay Mud and liquefiable fills. Due to the significant lateral loads 

expected from these soils on the retained cut side walls, horizontal support would be required. 

Temporary struts and rakers would be installed at various levels as excavation proceeds. 

Rigid and impermeable cut off would be used for the temporary side walls. The most 

economical method for building the cut-off walls is the Deep Mixing Method (DMM). This 

produces a wall commonly referred to as a soil cement wall. This method involves mixing of 

cement slurry with in-situ soil to construct a continuous and practically impermeable wall made 

up of individual columns. Each column is structurally reinforced with vertical steel beams that 

are inserted into the soil-cement mix while the mix is still fluid (i.e., before it sets and hardens). 

Such walls have the advantage that they are competitive economically, they minimize the risk for 

adverse impacts associated with ground deformations during excavation, and eliminate the need 

for costly dewatering. 

A specialized auger (Figure 5.20-1) is used in this process. This construction technique involves 

some displacement of soil (25-30 percent), which bubbles out of the auger hole onto the ground. 

This soil, which is mixed with the cement, would be left to harden and then be removed by truck. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5-166 5.20 CONSTRUCTION STAGING AND METHODS

The soil cement walls are typically constructed to extend deep and tie into an impermeable layer 

below the base of the planned excavation so that under seepage into the excavation can be 

minimized. The soil-cement walls would be used not only for temporary excavation support but 

also for permanent groundwater cutoff, a critical concern in this area where high ground water 

levels are anticipated. Figure 5.20-2 shows the drilling of auger holes and the creation of a soil 

cement wall. 

Equipment used for installation of soil-cement walls typically includes: a soil-mix wall rig for in 

situ soil mixing (see Figures 5.20-1 and 5.20-2), a soil-mix wall batch plant for grout 

preparation, a crane for installation of soldier piles, back hoe, rubber tired loaders and trucks. 

After the cut-off walls have been constructed, excavation would proceed from top down. The 

walls of the depressed yard area excavation would be supported with rakers and struts. Rakers 

would consist of heavy steel pipes. The first level of rakers is usually installed at a shallow 

depth. The excavation would then progress sequentially, and would not extend more than two to 

three feet below the level of the next required raker support, until the rakers are in place and 

secure. For the depths of excavation contemplated, three to four levels of supports are 

anticipated in the vertical plane. The walls of the adjacent depressed mainline track corridor 

would be strutted near the existing ground line for the deeper cut sections with heavy steel pipes. 

Groundwater within the excavation would be collected in sumps and pumped to a settling basin 

before it is disposed in accordance with applicable regulations. 

Permanent Structure Installation. After excavation is complete piles would be driven through 

out the bottom of the retained cut areas. These are required for the support of the permanent 

bottom slab. After piles are driven then the bottom slab would be constructed. The interior face 

of the soil cement piles would be removed to expose the flange of the steel pile. Steel shear 

connectors would be welded to the flange and reinforced concrete fascia wall would be cast 

against the steel piles to form the permanent side walls of the retained cut section. Interior 

support columns would be constructed next followed by permanent strut systems. A top slab 

would be constructed last over the depressed yard area. The strut and slab system over the 

depressed yard area would be used for parking or useable yard area. 

Equipment typically used for permanent subway structure construction includes: cranes, concrete 

trucks, trucks, concrete pumps, welding machines, generator/compressors, rubber-tired 

loader/bobcat and fork lift. 

Cut-And-Cover Construction. Cut-and-cover construction would be used from near Fifth 

Street at Station 31+00 to the west end to the Transbay Terminal at approximately Station 90+50, 

and from the east end of the terminal at approximately Station 104+50 to the end of the line at 

122+95 (Main Street Alternative). An alternative tunneling construction method is proposed as 

an alternative for a portion of this alignment from Station 51+00 to 81+00. This alternative 

method is described below and shown in Figure 5.20-3. In addition the Transbay Terminal will 

be constructed using similar methods to cut and cover and this is also described below. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND M

5.20 CONSTRUCTION STAGING AND METHODS 

Figure 5.20-1: Soil Cement Wall Augers in Use 
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5-168 5.20 CONSTRUCTION 

Figure 5.20-2: Column Construction for Soil Cement Walls 
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5.20 CONSTRUCTION STAGING AND METHODS 5-169 

Support of Adjacent Structures. The first step in cut-and-cover construction is to assure 

support for foundations of buildings adjacent to the excavation. Underpinning of buildings 

adjacent to the cut-and-cover sections is not anticipated at this point. Instead, control of potential 

movement of adjacent structures is proposed to be accomplished by use of excavation support 

systems, which, in conjunction with proper excavation and bracing or tie-back procedures, can 

serve as protection for the adjacent structures. This is common practice for the Bay Area and 

was successfully used for the Muni Metro Turnaround project at the east end of Market Street. 

The excavation support system currently proposed for this project is described in the following 

sections. During construction, adjacent buildings would be monitored for movement and, if 

movement is detected, take immediate action to control the movement.

General Approach to Temporary and Permanent Structures. The same approach will be 

followed as with retained cut construction wherein the temporary structure will be incorporated 

into the permanent structure. One exception will be in the area of the Transbay Terminal. The 

Transbay Terminal construction will construct separate temporary and permanent structures as 

described below. 

Temporary Structures and Excavation. The methods of excavation support vary with the 

ground conditions. The cut and cover alignment can be divided into three segments: (1) areas 

where the ground consists predominantly of soft soils with high groundwater conditions (along 

Townsend Street east of Fifth Street); (2) areas where the subsurface soils consist of stiff clays 

and/or dense sands (all remaining areas not described in segments 1 & 3); and (3) areas where 

the excavation will be in rock (along Second Street between Brannan and Folsom and along 

Main Street between Folsom and Harrison). The temporary support and structure systems that 

would be used within each of these three areas are described below 

Excavations in Soft Soils/Stiff Clays/Dense Sands – Excavation support and excavation in these 

soils will be the similar to that for the retained cut work in that soil cement walls would first be 

constructed. Prior to excavation deck beams and temporary decking would be installed at the top 

of the proposed excavation as described below. The deck beams and temporary deck maintain 

vehicular traffic during construction. After temporary decking is installed, excavation would 

proceed from top down. The walls of the excavation would be supported with internal struts or 

ground anchors (tie-backs) as excavation proceeds. 

The use of tie-backs is preferred over internal struts because they provide more of an 

unobstructed work area for excavation. Tie-backs, however, are not suitable for use in soft soils. 

In soft soils internal struts would be used. Tie-backs would be used in stiff clays and dense 

sands. 
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5-170 5.20 CONSTRUCTION STAGING AND METHODS

Figure 5.20-3: Retained Cut Construction 
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5.20 CONSTRUCTION STAGING AND METHODS 5-171 

In those locations tie-backs would be drilled from inside the excavation and could extend 

between 50 and 75 feet back from the face of excavation. The tie-backs consist of drilling a 

small diameter (5 to 6 inches) hole, installing the anchorage element, and filling the hole with 

grout. During the drilling process, the hole would be supported with steel casing to avoid caving 

of the ground, which can cause undesirable settlements. After the grout had gained sufficient 

strength, the anchors would be stressed and secured against the excavation walls. 

Because tie-backs would extend outside the excavation limits, and in many cases extend under 

existing structures along the project alignment, installation of tie-backs would require permission 

from the owners of the adjacent structures to install the temporary tie-backs under their property. 

This is a normal process and usually the necessary agreements between the project owner and the 

property can be negotiated. 

Internal struts, if used, would consist of heavy steel pipes spaced every 15 to 18 feet horizontally 

and 10 to 12 feet vertically. 

The excavation progresses sequentially, and does not extend more than two to three feet below 

the level of each horizontal support (tie-back or strut), until the supporting struts are in place and 

secure. For the depths of excavation contemplated for the downtown extension project, three to 

four levels of struts are anticipated. Groundwater within the excavation is collected in sumps 

and pumped to a settling basin before it is disposed in accordance with applicable regulations. 

Excavations in Rock - The Deep Mixing Method is not suitable in areas where rock is 

encountered. The most likely method of excavation support is to use cast in drilled hole (CIDH) 

piles spaced 8 to 10 feet along the alignment. The piles are constructed by using an auger to drill 

a hole (approximately 36” in diameter for this project) to a depth of 5 to 10 feet below bottom of 

permanent subway structure. Steel columns are then set in the holes and encased in concrete. 

The exposed rock in the spaces between the piles is sprayed with shotcrete to hold the rock in 

place. 

After the CIDH piles have been installed along both sides of the excavations, deck beams and 

temporary decking is installed as described below. Excavation then progresses in stages from 

top down. Lateral support for the excavation would be provided using either internal struts or 

rock anchors. Rock anchors are generally preferred over internal struts because they provide an 

unobstructed area in the excavation. This makes operation of excavation equipment much easier 

than if struts were present. Rock anchors would be spaced about 10 foot horizontally and 14 foot 

vertically. 

Excavation of the rock would be carried out, most likely using heavy excavating and ripping 

equipment. Where hard rock is encountered, blasting may be required. However, given the 

condition of the rock in the study area, which is highly fractured and weathered, blasting, if 

required, is anticipated to be minimal. 

Dewatering from inside the excavation would be required. The quantities of seepage should be 

small enough to be manageable with interior sumps and pumps. It is anticipated that predraining 

using deep wells will not be effective in the Franciscan rock formation to be encountered. 
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5-172 5.20 CONSTRUCTION STAGING AND METHODS

The equipment required for installing excavation support and for excavation is identified in the 

Retained-Cut section above. 

Temporary Decking Installation. Temporary roadway decking would be installed in 

progressive stages over the proposed cut. Prior to beginning of excavation of the cut, lateral 

trenches would be excavated across the alignment from one sidewall to the other to permit 

installation of deck beams. These trenches are generally excavated during the nighttime and 

covered to permit normal traffic flow during the day. When a sufficient number of deck beams 

have been installed, a shallow excavation of approximately eight feet in between the deck beams 

is made. This excavation is designed to uncover buried utilities and to provide room for 

continuing the excavation after the temporary decking is erected. 

As deck beams are installed, the utilities that can remain in the trench area (e.g., telephone, 

traffic, electric) would be cradled, picked up, and hung from the deck beams. Sewer lines may 

exist at this shallow depth and likewise would be hung from the deck beams during the initial 

excavation stage. Utilities located deeper would be uncovered fully after additional depth of 

excavation had been accomplished. Sometimes heavy utilities such as large sewer pipes are 

supported by an auxiliary set of beams spanning between the side walls rather than hanging them 

from the deck beams. When utilities cannot be relocated outside the excavation or when they are 

being moved, there is a small chance of damage during excavation, causing a utility outage that 

can last for a few minutes to a few days. Most of the risk of hitting utilities is caused by actual 

utility locations being different from those shown on construction drawings. Utility service will 

be returned as quickly as possible after an outage. 

Decking is then placed on top of the deck beams. It is proposed that the decking be set flush 

with the existing street and sidewalk levels. Roadway traffic can then be restored while 

excavation will proceed underneath. Figure 5.20-4 illustrates the cut-and-cover excavation and 

decking process. Decking at cross-streets would be installed in stages to allow at least half of the 

existing traffic lanes to be maintained. After installation of the deck, full cross-street traffic 

could be maintained for the duration of construction. 

Equipment typically used for decking, excavation, and bracing includes: crawler dozer/loader, 

water pump, rubber-tired loader/bob cat, pavement breaker, excavator/backhoe, conveyer 

system, truck, crane, generator/compressor, and fork lift. 

Permanent Structure Installation and Backfill. After completion of excavation the permanent 

subway structure would be constructed. In the areas of soft ground encountering Bay Mud, piles 

would be driven to support the base slab of the permanent structure, followed by construction of 

the base slab itself. In other locations where the soils under the base slab are more suitable, the 

base slab would be poured on grade. After the base slab is constructed the vertical fascia walls 

would be constructed starting at the bottom and proceeding up. The internal struts are removed 

one by one as the walls of the box structure are raised. The concrete encasement on the internal 

face of the CIDH piles would be removed back to the face of the steel column. Steel shear 

connectors would be welded to the column and a reinforced concrete fascia wall would be cast 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-173 

against the steel columns to act together to form the permanent sidewalls. In the deeper cut 

sections intermediate level permanent struts constructed of reinforced concrete would be 

installed between the sidewalls to provide permanent lateral support. Also in wider cuts 

intermediate columns would be constructed to support the top slab. A top slab constructed of 

reinforced concrete would be installed last following by backfilling of 8 to 10 feet of earth fill. 

Road reconstruction would then occur on top of this backfill. Figure 5.20-5 illustrates 

installation of the permanent subway structure. 

Figure 5.20-4: Cut-and-Cover Excavation and Temporary Decking 
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5-174 5.20 CONSTRUCTION STAGING AND METHODS

Figure 5.20-5: Cut-and-Cover Subway Construction

Equipment typically used for permanent subway structure construction includes: cranes, concrete 

trucks, trucks, concrete pumps, welding machines, generator/compressors, rubber-tired 

loader/bobcat and fork lift. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-175 

Alternative Tunnel Construction. The use of tunneling methods is an alternative to cut-andcover construction in areas of rock formations. Core drillings were taken in the corridor in 1996, 

and the rock was identified as “fractured rock.” A panel of experts46 recommended that a 

“specialized tunneling” technique known as “spiling” be used in this rock. Because the proposed 

Caltrain Extension Alternatives Tunneling Option includes a larger tunnel (three tracks instead of 

two) than was proposed in 1996 and passes under historic structures, a tunneling technique 

known as “stacked drift” is now proposed. Due to the poor nature of the rock quality and the 

large clear spans required for the tunnel structure, this special tunneling method would be 

employed to minimize the risk of cave-ins during construction. The Tunneling Option is 

proposed for Station 51+00 (Townsend Street just east of Third Street) to Station 81+00 (Second 

and Folsom Streets). 

A series of contiguous drifts approximately nine feet wide and about nine feet tall would be 

constructed around the perimeter of the tunnel sidewalls and roof, starting from the invert and 

moving towards the crown of the tunnel. (See Figure 5.20-6). 

The individual drifts would be excavated by hand mining methods, using spiling as required, to 

maintain stability of the roof, and using steel support members in combination with timber 

lagging to support the walls and stabilize the tunnel (see Figure 5.20-7). Once a drift is 

completed, a specially fabricated segmented ring support beam would be installed in the drift and 

encased in concrete. Steel reinforcement would be provided to develop the necessary strength. 

The portion of the drift that will eventually become part of the final tunnel excavation would be 

filled with slurry concrete that can be easily excavated during tunnel excavation to expose the 

ring beam and tunnel lining. 

After construction of the tunnel support system (concrete encased ring beam), the tunnel itself is 

excavated in stages using a top heading and a bench. Road headers and other suitable excavating 

equipment can be used to excavate the rock cavern within the already constructed ring beam. 

Because the rock is viable, some limited blasting may be required. Access to the tunnel’s 

construction would be from either end and from a vertical access shaft near Second and Brannan 

Streets. From the midpoint access construction of the tunnel would proceed in either direction to 

speed construction of the tunnel to meet schedule demands. These three access points would be 

used for equipment and labor access and for egress of excavated material. 

 

46 The panel included Professor Thomas D. O’Rourke of Cornell University, Professor Tor L. Brekke of the 

University of California, Berkeley, and Mr. Norman A. Nadel, of Nadel Associates, Brewster, New York. The 

Panel was chaired by Demetrious Koutsoftas, URS, San Francisco, who has extensive experience with development 

and tunnel projects in the Project Area and a substantial knowledgeable regarding the Project area’s geology. 
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5-176 5.20 CONSTRUCTION STAGING AND METHODS

Figure 5.20-6: Stacked Drift Tunnel Construction 
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5.20 CONSTRUCTION STAGING AND METHODS 5-177 

Figure 5.20-7: Typical Tunnel Drift Construction 
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5-178 5.20 CONSTRUCTION STAGING AND METHODS

Equipment used for tunnel construction includes: rubber tired front end loader/bobcats, air 

compressors, generators/compressors, pneumatic tools, fork lifts, dump trucks, small rubber tired 

cranes. 

Transbay Terminal and Related Facilities Construction. Transbay Terminal construction 

would be very similar to cut-and-cover and retained cut construction methods as it will also 

make use of soil cement walls and ground anchors. It will differ in that the soil cement walls 

will be used only in the temporary condition. The permanent terminal structure will be 

constructed inside the soil cement walls as an independent structure. After the permanent 

structure is constructed the temporary soil cement walls and ground anchors are abandoned in 

place. After the soil cement walls are constructed then excavation would proceed from top 

down. Excavation would not proceed more than two to three feet below the level of the next 

required level of ground anchors until they were installed. 

Related Temporary and Permanent Facilities. There are proposed facilities to be constructed 

in the general area south of the Transbay Terminal that provides for the operation of temporary 

and permanent bus service. These facilities include the following: 

• Permanent Transbay Terminal and Access Ramps 

• Temporary Transbay Terminal 

• Permanent Offsite Bus Storage and Access Ramps 

All bus access ramps would be aerial structures most likely constructed of reinforced concrete. 

In areas with shallow underlying rock, the foundations would be concrete spread footings. In 

softer underlying soils, pile supported foundations would be constructed. Falsework would be 

required to support the forms for constructing the elevated structures. Falsework would span 

over existing roadways to be kept them open during construction. 

The temporary Transbay Terminal and permanent offsite bus storage areas are simple facilities 

constructed on existing grades. Existing minor improvements on these sites would be removed 

and the sites graded for the new improvements. New improvements would consist mainly of 

paving for bus storage or travel ways. In the temporary terminal pedestrian platforms and 

walkway areas would be constructed along with some with canopy shelters. 

Equipment for construction of these facilities would include: pile drivers, trucks, dump trucks, 

air compressors, graders, front end loaders, excavators, backhoes, and small rubber tired cranes. 

Quantity of Excavated Materials. Table 5.20-4 identifies the estimated number of cubic yards 

of material to be removed during construction of the track corridor alignment and Transbay 

Terminal. Excavation quantities for the other related projects to the Transbay Terminal can be 

considered as negligible in comparison to the below quantities. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-179 

Table 5.20-4: Estimated Amounts of Excavation Materials

Construction Site Location Estimated 

Cubic Yards [a]

Second-to-Main Alternative (Retained Cut, Cut and Cover) 

Ex. Yard and Townsend Street 729,400 

Second Street to Transbay Terminal 999,000 

Transbay Terminal 658,100 

Transbay Terminal to End 322,200 

Total 2,708,700 

Second to Mission Alternative (Retained Cut, Cut and Cover) 

Ex. Yard and Townsend Street 729,400 

Second Street to Transbay Terminal 999,000 

Transbay Terminal 658,100 

Transbay Terminal to End 486,800 

Total 2,873,300 

Second-to-Main Alternative (Retained Cut, Cut & Cover, Tunneling) 

Ex. Yard and Townsend Street 729,400 

Tunnel from Townsend to Second Street at Folsom Street 336,000 

Second Street at Folsom Street to Transbay Terminal 301,300 

Transbay Terminal 658,100 

Transbay Terminal to End 322,200 

Total 2,347,000 

Second-to-Mission Alternative (Retained Cut, Cut & Cover, Tunneling) 

Ex. Yard and Townsend Street 729,400 

Tunnel from Townsend to Second Street at Folsom Street 336,000 

Second Street at Folsom Street to Transbay Terminal 301,300 

Transbay Terminal 658,100 

Transbay Terminal to End 486,800 

Total 2,511,600 

Note: [a] This column includes an estimated 1.15 expansion factor for soil and 1.5 expansion factor for rock 

and demolished concrete due to bulking upon excavation/demolition. 

Street Reconstruction. To fully restore permanent street traffic, temporary decking would be 

removed, the remainder of cut-and-cover sections would be backfilled, permanent utility 

restoration would occur, and the permanent street improvements would be installed. With 

restoration of roadway pavement and vehicular traffic, the surface work on the project would be 

completed and continuing activity involving subway finishes and equipment installations (e.g., 

installation of tracks, power, signals, and communication systems) could continue beneath the 

surface with minimal disruption to street use by vehicles and pedestrians. 

Equipment typically used for street reconstruction includes: rubber-tired loaders/ bobcat, roller/ 

compactors, dump trucks, and paving machines. 
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5-180 5.20 CONSTRUCTION STAGING AND METHODS

5.20.3 CONTRACTOR WORK AREAS

Contractor work areas (or construction staging areas) would be needed for the surface, retained 

cut, and cut-and-cover construction segments of the proposed extension. Following are the 

proposed contractor work areas: 

1. East of Seventh Street, between Berry and Townsend Streets at the westernmost end of 

the existing Caltrain Yard. 

2. North of Townsend Street, east of Clarence Place and west of Stanford Street, at the site 

of buildings that would be taken and demolished for the Caltrain Downtown Extension. 

3. The Southwest quadrant of the intersection of Second and Brannan streets, at the location 

of buildings to be demolished for the construction of the Caltrain Downtown Extension. 

4. The northeast quadrant of the Howard Street/Second Street intersection, at the site of 

buildings to be demolished for the construction of the Caltrain Downtown Extension. 

5. The parking lot west of Main Street between Howard and Mission streets. 

Contractor work areas, if alternative tunneling construction methods were used, would be as 

follows. There are fewer areas due to the reduction in demolition of existing buildings. 

1. East of Seventh Street, between Berry and Townsend Streets at the westernmost end of 

the existing Caltrain Yard. 

2. North of the intersection of Second and Brannan Streets. 

3. The northeast quadrant of the Howard Street/Second Street intersection, at the site of 

buildings to be demolished for the construction of the Caltrain Downtown Extension. 

4. The parking lot west of Main Street between Howard and Mission streets. 

Activities that would occur at these sites primarily include stockpiling of materials and storage of 

equipment. It is expected the contractor would rent local office space for their construction 

office to house administrative staff. Equipment employed for cut-and-cover is typically heavy 

duty, high volume machinery. Such equipment requires certain amounts of space when standing 

still, more for turning, and additional for maneuvering. 

5.20.4 ANCILLARY FACILITIES

Ventilation and emergency access shafts will be required for the tunnel portion of the Caltrain 

Downtown Extension. Following is a discussion of anticipated locations and impacts of these 

facilities. The final locations for these shafts are subject to change during final design. 

Tunnel shafts and ventilation systems provide the following capabilities: 

• Heat Removal - During normal conditions, tunnel ventilation is achieved by natural 

ventilation consisting primarily of train piston-action induced airflows. Fans housed in shafts 

are provided to augment the natural ventilation provided by the train piston action during 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATIONS MEASURES 

5.20 CONSTRUCTION STAGING AND METHODS 5-181 

normal operations and, when necessary, provide the primary means of limiting the tunnel 

temperatures when train piston action induced airflows are no longer present. 

• Smoke Control - An “emergency” mode of operation for smoke control and discharge is 

provided using remote and overriding local fan controls. 

• Air Movement (piston action) Relief - Vent shafts are typically provided at each end of 

underground stations to reduce excessive air movement within stations due to piston-action of 

trains 

• Emergency Egress – National Fire Protection Association Standard (NFPA) 130 requires 

exit shafts to the surface at maximum 2,500 foot centers (reference NFPA 130 2003, 

paragraph 6.2.4.2). Where practical, ventilation shafts may also include emergency 

stairways. The portal at the Townsend station may be considered an exit since this station is 

proposed as an open cut section. 

• Air Intake/Exhaust – In the case of a dead end tunnel, a means of providing an air intake 

and/or exhaust shaft is necessary for the ventilation system to function properly. 

Ventilation Shafts. For the Locally Preferred Alternative, it is assumed that ventilation shafts 

housing fans and bypass dampers would be provided at each end of the new Transbay Terminal 

These shafts would house a minimum of two reversible fans and associated equipment consisting 

of sound attenuators and fan dampers. Bypass dampers would also be provided for additional 

air movement (piston-action) relief. The ventilation equipment would be located above the train 

tracks. The discharge of each shaft would be incorporated into the terminal structure. The foot 

print for these facilities would be approximately 200 square feet (10 by 20 feet). 

Air intake/exhaust shafts would also be located in the sidewalks along Main Street just north of 

Harrison, near the end of the proposed tail tracks. These shafts would also include emergency 

exits. Since the Townsend Street Station is in an open cut, ventilation shafts would not be 

required at this station. 

Emergency Exit Shafts. In addition to the emergency exits assumed north of Harrison Street in 

the Main Street sidewalks as described above, tunnel emergency exit shafts are also assumed at 

Second and Brannan Streets and at Second and Howard Streets. With emergency exits also 

assumed at both ends of the Transbay Terminal, this would result in an average distance 

between shafts of approximately 1,610 feet – within the requirements of NFPA 130. The shafts 

would be constructed as part of the cut-and-cover construction for the Second at Folsom and 

Main at Harrison locations and as part of the tunnel construction access shaft assumed at 

Second and Brannan Streets. At completion, the shafts would lead to a metal door located in 

and flush with the sidewalks along Second and along Main Streets. These emergency access 

shaft doors would be locked from the surface and would open from the underside leading from 

exit stairways in an emergency. 

Emergency Generator. A diesel-powered emergency generator, to operate critical terminal 

functions (e.g., emergency lighting, escalators), would be installed at one end of the terminal. 

This facility would also need to be vented to the surface. The generator would need to be tested, 

typically at one month intervals, so noise mitigation would be provided. 
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5-182 5.20 CONSTRUCTION STAGING AND METHODS

Environmental Impacts. No long-term impacts (visual, noise, etc.) would be associated with the 

anticipated emergency exits given that they would be flush with the sidewalk surface. 

Construction impacts from these facilities are described below for the cut-and-cover 

construction that would occur at these locations. 

It is assumed that the fan located at the west end of the terminal would be operated only during 

emergencies. During normal operations (i.e., trains moving more or less as scheduled), piston 

action is typically sufficient to prevent heat build-up. 

Local codes will require some means of ventilation for the tail track, which would be provided by 

the fan located at the east end of the terminal. It is assumed that one of the two fans serving the 

tail tracks would be operated during periods when the light train servicing is occurring. Both 

fans would operate if an emergency occurred. As an option, both fans could be operated at a 

reduced speed. 

Walls would be located around the surface access for both fan facilities and around the 

emergency generator to mitigate noise and prohibit public access to the ventilation equipment 

for security purposes. Noise walls would be designed to assure adherence with FTA noise levels. 

Land uses immediately surrounding the new terminal at either end are primarily 

commercial/office. 

The land uses immediately surrounding the vent structure and emergency exits at Main just north 

of Harrison are also commercial/office. This shaft would operate as an air intake/exhaust shaft 

to provide make-up air for the tunnel ventilation fans installed at the terminal. The shaft would 

be located near the far end of the tail track to allow fan induced airflow to sweep the entire 

length of the tail track tunnel. This shaft would terminate at the surface, under local sidewalks, 

with a grating. Air/intake shaft mechanical equipment would be limited to a damper that opens 

whenever the tunnel ventilation fans operate and closes upon fan shutdown. Given the 

surrounding land uses and facility operation, no environmental impacts are anticipated. 

5.20.5 CONSTRUCTION PHASING

Figure 5.20-8 shows the schedule for construction of the Transbay Terminal and the Caltrain 

Downtown Extension. 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MIT

5.20 CONSTRUCTION STAGING AND METHODS 

Figure 5.20-8: Estimated Construction Phasing for Transbay Terminal and Caltrain Downtown E

Calendar Years 2004 2005 2006 2007 2008 

Activity Months 1-6 7- 12 13- 18 19- 24 25- 30 31- 36 37- 42 43- 48 49- 54 55- 60 6

6

Operations Analysis, Preliminary Engineering, Geotechnical Engineering Program Review/Value Engineering Final Design & Permitting – Transbay Terminal Final Design & Permitting – Caltrain Extension Acquire Property, Design, Construct Temporary Terminals (Transit and Greyhound) Acquire Property & Demolish Buildings along Caltrain Extension Design and Relocate Utility Lines along Caltrain Extension Construct Surface Rail & Improvements at Caltrain Fourth and Townsend Yard Construct Cut-and-Cover and Retained-Cut – Caltrain Extension Reconstruct Streets Construct Caltrain Tunnel Construct Caltrain Track & Systems Facilities Demolish Existing Transbay Terminal & Ramps, Construct New Terminal & Ramps Construct Permanent Off Site Bus Storage Facility [a] Assumes West Ramp, Second–to–Main, Tunnel Option
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5-184 5.21 CONSTRUCTION IMPACTS

5.21 CONSTRUCTION IMPACTS 

The following sections evaluate the impacts and mitigation measures for the construction 

scenarios described above. 

5.21.1 TRANSIT OPERATIONS

This section reviews the effects of Terminal/Extension Project construction on transit operations. 

Construction of the Transbay Terminal and underground Caltrain Station would require the 

establishment of a temporary bus terminal, the rerouting of transit lines, and the reconfiguration 

of roadways surrounding the temporary bus terminal. Transit operations on other roadways in 

the project area would also likely be affected and are addressed at the end of this section. 

The impacts assessment is based upon preliminary planning for the temporary terminal as 

described in SMWM’s Working Paper 12 “Terminal Design Modifications and Refinements” 

and in Section 3 of Arup’s Working Paper 7.0 Pre-Concept Engineering Report. 

5.21.1.1 Temporary Terminal Operations 

The temporary terminal would be built on the single square block defined by 

Main/Beale/Folsom/Howard Streets. The core of the temporary terminal would serve AC 

Transit’s transbay operations and midday bus storage. The perimeter of the terminal would 

accommodate Muni drop-off, layover, and pick-ups as well as Golden Gate Transit pick-ups. 

Greyhound buses would board and alight passengers at a separate, adjacent terminal on the west 

side of Beale Street between Folsom and Howard Streets (see Figure 5.21-1). 

New overhead power distribution wires would be required for the rerouting of Muni Trolley 

buses on Folsom Street between Beale and Main; Howard Street between Beale and Main; Main 

Street between Howard and Folsom, Beale Street between Mission and Folsom; and Fremont 

Street between Mission and Howard. 

Proposed Access to/from the Temporary Terminal for AC Transit Buses 

In response to public comment regarding the need to reduce overall project costs, the co-lead 

agencies have identified alternate AC Transit bus access to the temporary terminal to avoid the 

need for a temporary bus ramp between the Bay Bridge and the temporary terminal during 

operation of the temporary facility. Without a temporary bus ramp, the buses exiting the freeway 

would use local streets to gain access to the temporary terminal between Main, Beale, Folsom, 

and Howard Streets. AC Transit buses exiting the I-80 freeway would go north up Fremont from 

the Harrison Street ramp, turn east on Folsom and proceed eastbound toward the temporary 

terminal. For the return trips, there would be a contra-flow lane along Folsom from Main Street 

to Essex Street for buses exiting the terminal. Buses would then have a protected left-turn 

movement from Folsom onto Essex Street. Once on Essex, the buses would travel on a dedicated 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5.21 CONSTRUCTION IMPACTS 5-185 

bus lane toward the freeway on ramp. Figure 5.21-2 shows these access routes for buses while 

approaching and leaving the temporary terminal. 

 Figure 5.21-1: AC Transit, Muni, and Golden Gate Transit Access to the Temporary Terminal 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5-186 5.21 CONSTRUCTION IMPACTS

Traffic turning movement data for 2000 and 2020 were obtained from an earlier study done by 

Wilbur Smith Associates. The traffic volumes for 2006 were determined by linear interpolation. 

Traffic analysis was done for the P.M. peak period – from 5:00 to 6:00 p.m. AC transit bus 

counts were obtained from AC Transit, through their check sheet for buses at Transbay 

Terminal. Golden Gate buses were assumed to add 30 buses per hour to the eastbound traffic on 

Folsom Street as they returned from the off-site storage in the P.M.-peak period. Using SIGNAL 

94 from TEAPAC, key intersections were analyzed for the “with” and “without a temporary 

ramp” condition to the temporary terminal. The analysis year for all construction detour 

analyses was 2006 – the midpoint of the construction schedule. 

Table 5.21-1 summarizes the intersection traffic and level of service data on the selected five 

intersections near the temporary terminal, with and without the additional buses and with 

contra-flow lane. For the no-ramp condition, there were no intersections that would degrade to 

Level of Service E or F assuming the operation of the bus lane along Folsom Street. At 

intersections where the contributions of the additional buses and the contra-flow lane were 

found to be adverse, traffic would be added to movements that would continue to operate 

satisfactorily. 

 

There are two intersections in the Bay Bridge queue, however, that are projected to operate at 

LOS F both with and without the bus lane: First and Folsom, and Essex and Harrison. With the 

contra-flow lane, First and Folsom would have a slightly higher V/C ratio while Essex and 

Harrison would be about the same. The increase in the V/C from 1.35 to 1.38 at First and 

Folsom is not an adverse effect under the City and County of San Francisco criteria. It should 

be noted that at this intersection, the southbound traffic on First Street represents the major 

volumes at the intersection, thus contributing heavily toward the high V/C at the intersection. 

The east-west bound traffic on Folsom is much lower, and the buses, although an addition to the 

existing traffic during 2020, would travel on a dedicated lane, westbound on Folsom. Hence, the 

contribution to the traffic conditions from the buses in the dedicated lane would not be severe. 

At the Essex and Harrison intersection, the northbound lanes of Essex Street that currently have 

very light traffic would be converted to southbound lanes. With two mixed-flow lanes and a 

dedicated bus lane in the southbound direction on Essex, the V/C ratio at Essex and Harrison 

would slightly improve from the existing condition. 

As a result, the traffic generated by the additional buses and contra-flow lane would not 

represent a considerable contribution to the existing conditions and there would be no severe 

adverse traffic impacts at these intersections. 
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5.21 CONSTRUCTION IMPACTS 5-187 

Figure 5.21-2: AC Transit Access Routes to/from the Temporary Terminal
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5-188 5.21 CONSTRUCTION IMPACTS

Table 5.21-1: Level of Service Calculations for Contra-Flow Bus Lane from 

Temporary Bus Terminal to Bay Bridge via Folsom 

2006 Conditions with and without the Additional 

Buses and Contra-Flow Bus Lane 

Without Buses With Buses 

Intersection V/C Delay LOS V/C Delay LOS 

Main and Folsom 0.29 6.6 B 0.86 35.5 D 

Beale and Folsom 0.47 8.4 B 0.65 10.4 B 

Fremont and Folsom 0.34 7.4 B 0.43 6.3 B 

First and Folsom 1.35 >60* F 1.38 >60* F 

Essex and Folsom 

Unsignalized 

Intersection 0.8 15.8 C 

Essex and Harrison 

with two southbound mixed flow lanes 1.25 >60* F 1.22 >60* F 

Fremont and Harrison 0.77 13.1 B 0.78 14 B 

*LOS is based on V/C ratios for intersections with V/C > 1. 

Source: Parsons, July 2003. 

5.21.1.2 Transit Operations 

The creation of a temporary Transbay Terminal would allow uninterrupted service for AC 

Transit, Muni, Golden Gate Transit, SamTrans, and Greyhound while the permanent facility is 

under construction. Each of these transit services would be required to modify operations during 

the operation of the temporary terminal. 

AC Transit. The temporary facility is designed to fully accommodate AC Transit operations. 

Sufficient midday bus storage would be provided within the temporary terminal; therefore, AC 

Transit would not incur additional operating costs due to deadheading. AC Transit buses would 

circulate counterclockwise around a central bus parking lot. Surrounding the bus right of way 

would be 16 saw tooth bays. Passengers would board and alight from the perimeter sidewalk 

around the terminal and no internal crosswalks would be needed.47 

The operation of AC Transit in the temporary terminal was analyzed using a local area network 

simulation model, VISSIM. The analysis determined that the temporary terminal had sufficient 

capacity for AC Transit to operate and store buses during afternoon peak conditions when 

occupancy of the terminal’s center area, including the buses operating within the AC Transit 

storage/staging area, is highest. The study also demonstrated there would be sufficient bus bays 

available in the temporary facility during maximum occupancy. Maximum queues (8 buses) in 

the circulation area would dissipate in about one minute.48 

 

47 Arup, Working Paper 7.0 Pre-Concept Engineering Report, p. 23 

48 SMWM Working Paper 12 Terminal Design Modifications and Refinements, p. 68 -71 
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5.21 CONSTRUCTION IMPACTS 5-189 

Muni. Muni routes currently serving the Transbay Terminal include lines 5, 6, 38, and 38L. 

They would be rerouted to board and alight passengers around the periphery of the temporary 

terminal. Muni lines 2 and 3 are also expected to serve the temporary terminal. 

Terminal-bound Muni routes would be extended an extra one or two blocks on Market Street, 

proceed south down Beale Street, and continue along Howard Street to access the temporary 

facility. Buses would circulate clockwise around the terminal’s perimeter, enabling passengers 

to load on the opposite side of the same curb/loading area used by AC Transit buses circulating 

counterclockwise within the terminal. Muni trolley buses would use drop-off bays along the 

south side of Howard Street and lay over along Folsom Street at the south end of the temporary 

terminal. Diesel operated buses would use two drop-off bays located along Main Street. All 

Muni vehicles would board passengers at the four northernmost bays along Beale Street. 

Muni estimates that the additional annual operating and maintenance costs associated with the 

Temporary Transbay Terminal will be just under $1 million in FY 2000 dollars. These 

additional costs are expected to result from the rerouting of the 2,5,6, and 38/38L lines. 

Simulation modeling demonstrated that there would be adequate capacity within the facility to 

accommodate Muni’s existing service during peak periods. The maximum queue exiting the 

terminal at Beale and Howard Streets would be four vehicles. This assumes the addition of a 

bus-only left-turn phase to the intersection’s existing signal.49 

Golden Gate Transit. The temporary terminal would accommodate Golden Gate Transit 

staging, boarding and alighting but not midday storage. Since AC Transit is expected to use the 

full storage capacity of the temporary terminal, Golden Gate Transit would require an off-site 

storage location and likely incur additional operating costs due to deadheading between the 

location and the temporary terminal. The preferred location of an off-site storage area and a 

rerouting plan have not been identified. Golden Gate is currently evaluating alternative bus 

staging areas with the pending loss of its lease for the current storage site. The lease termination 

is not an effect of the proposed project. 

Buses would access the temporary facility proceeding eastbound on Folsom Street and turning 

left onto Beale Street. Passengers could board at any of three bays reserved for Golden Gate 

along the eastern edge of Beale Street. An additional bay would be available on Beale Street for 

use by either Muni or Golden Gate Transit. A staging area for buses waiting to board and alight 

passengers would be available along the northern edge of Folsom Street between Fremont and 

Beale Streets. The precise access route for Golden Gate Transit to the temporary terminal will 

depend on the location chosen for its off-site storage area. 

 

49 SMWM, p.72. 
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5-190 5.21 CONSTRUCTION IMPACTS

Greyhound. Greyhound buses would not be accommodated within the temporary terminal but 

have a separate boarding area on the southern end of the block bounded by 

Beale/Fremont/Folsom/Howard Streets. The proximity of this location to the temporary terminal 

would facilitate connections between Greyhound, AC Transit, and Muni. 

SamTrans. During the construction phase, SamTrans express bus service would operate via 

Mission, Beale, Folsom and Main Streets to an endpoint terminal on Beale between Howard and 

Folsom, or as an alternative, on Main between Folsom and Howard. Buses would alight 

passengers at all bus stops prior to the endpoint. Leaving the endpoint, buses would be in service 

and stop at all bus stops for passenger boarding. This operation would result in the elimination 

of 11 parking spaces on the south side of Mission Street between Fremont and Beale Streets. 

5.21.1.3Changes to Surrounding Road Network 

In order to facilitate movements to and around the temporary transbay facility, several physical 

and operational improvements would be made to the surrounding roadways. These changes are 

shown in Figures 5.21-1 and 5.21-2. The effects on bus operations are described by arterial. 

Beale Street. The segment of Beale Street between Howard and Folsom would be reconfigured 

to accommodate a northbound contra-flow dedicated bus lane and a separate lane for bus loading 

and staging along the curbside of the temporary Terminal. The contra-flow bus line would be 

used by both Muni and Golden Gate Transit. The northernmost end of the bus-loading lane 

would be used for Muni boarding and alighting. The southernmost end would be used by 

Golden Gate Transit. New overhead power distribution wires would be added to support Muni 

trolleybuses. 

Reconfiguring Beale Street would require the elimination of two southbound traffic lanes and 12 

curbside parking spaces on Beale Street. A four-foot-wide median would be built between the 

two remaining southbound lanes and the new bus lane. Additionally, the casual carpool lane, 

currently on the east side of Beale Street, would be relocated to the west side of the street. 

The segment of Beale Street between Mission and Howard would also be reconfigured to 

accommodate a new boarding island for Muni’s Line 1 and a southbound bus-only lane. New 

overhead wires would also be provided above this segment to accommodate Muni trolleybuses. 

Folsom Street. Folsom Street between Beale and Main Streets would be reduced from four 

lanes eastbound to two lanes of eastbound traffic with the addition of a westbound contra-flow 

bus-only lane for Muni and Golden Gate Transit. The bus lane and the traffic lanes would be 

separated by a four-foot-wide striped median. Nine automobile parking spaces would be 

removed along the north curb of Folsom Street and replaced with a bus loading/staging lane. 

The bike lane and parking on the south side of Folsom would not be changed. New overhead 

wires would be added to support Muni trolleybuses. 
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5.21 CONSTRUCTION IMPACTS 5-191 

Main Street. Main Street’s three northbound traffic lanes between Howard and Folsom Streets 

would be changed to provide two lanes northbound and a southbound contraflow bus-only lane. 

All 48 motorcycle parking spaces and nine automobile spaces would be removed from the west 

side of Main Street and replaced with a curbside bus loading/staging lane. Overhead wires 

would be installed to accommodate Muni trolleybuses. 

Howard Street. Existing traffic lanes on Howard Street, the northern border of the temporary 

terminal, would not be changed during construction of the new Transbay Terminal but on-street 

parking would be removed between Beale and Main Streets. The north parking lane would be 

converted to provide another westbound travel lane and the south parking lane would become a 

bus loading/unloading area for Muni. 

5.21.1.4 Other Construction Impacts 

Construction of the new Transbay Terminal will also affect transit operations on other roads in 

the study area. 

Mission Street. Muni, Golden Gate Transit, and SamTrans would continue to operate along 

Mission Street in front of the terminal site during construction. However, construction generated 

traffic could potentially result in temporary delays for these operations. The Second-to-Mission 

Alternative would also require block-by-block closures on Mission Street to construct the cutand-cover subway between Beale Street and The Embarcadero. Muni’s Line 14 line currently 

operates on Mission Street and would be rerouted or turned back temporarily in sequence with 

construction activity. The bus circulation via a contra-flow bus lane on Main Street for the 

temporary terminal would not be affected since the buses would be moved back to the new 

Transbay Terminal before the block between Howard and Folsom would be affected. 

Second Street. The cut-and-cover construction of the Caltrain rail tunnel would require blockby-block closures of Second Street. Muni’s Line 10 line currently operates on Second Street and 

would be rerouted temporarily in sequence with construction activity. 

Third Street. In order to accommodate construction on Second Street, Third Street may be 

restriped to accommodate southbound vehicular traffic. The additional traffic could affect the 

performance of Muni’s service on Third Street, including lines 15, 30, 45 and 81x. 

Main Street. The Second-to-Main Alternative would also require block-by-block closures on 

Main Street to construct the cut-and-cover subway from south of Howard Street to just south of 

Harrison Street. Muni’s 1, 80X, and 82X lines and multiple Golden Gate lines currently 

operates on Main Street and would be rerouted temporarily in sequence with construction 

activity.
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5-192 5.21 CONSTRUCTION IMPACTS

5.21.2 VEHICULAR TRAFFIC 

5.21.2.1 Construction Trucks and Staging Areas 

The number of construction trucks projected to be on the city streets for this analysis is based on 

the estimated volume of debris to be removed, the amount of materials to be brought in, the 

average capacity of the trucks, and the approximate time of operation. The following analysis is 

for the Cut-and-Cover Second-to-Mission Alternative, which has 2.8 million cubic yards of 

material to be excavated (Table 5.20-4). This option represents a “worst case analysis.” Fewer 

trucks would be required for the Second-to-Main Alternative. Moreover, substantially fewer 

trucks would be required for the Tunneling Option for either alternative, in that the tunneling 

option would have sizably less excavated material. The Locally Preferred Alternative is the 

Second-to-Main Tunneling Option, which would generate about 20 percent less total excavated 

material than assumed in this worst case analysis. 

For the Second-to-Mission Cut-and-Cover Option analysis, the construction period is assumed to 

be two years, with an average hauling period of eight hours per day for 360 days per year less ten 

percent. Truck size is assumed to be 20 cubic yards. Soil is assumed to expand by 15 percent 

and rock by 50 percent. In general, it is assumed that spoils will be hauled by truck to the 

Caltrain yard adjacent to Seventh and Townsend and loaded onto trains for disposal out of the 

area. Disposition of the excavated materials will be the responsibility of the contractor. Any 

hazardous materials will need to be disposed of according to federal and state laws and 

regulations governing its hauling and disposition (see Section 5.21.15.). The actual location for 

the use (e.g., as fill material) or disposal of non-hazardous excavated materials will depend on 

the demand for such materials at the time of construction and/or the ability to dispose of these 

materials at a site to be determined by the contractor. Construction materials would be brought 

in only by truck. 

The planned staging areas are the following: 

• Portions of the Seventh and Townsend yard, 

• Along the corners of the Second Street alignment between Brannan and Townsend, 

• Northeast quadrant of Howard and Second, and 

• Northwest quadrant of Howard and Main. 

The volume of haul debris has been estimated based on planned dimensions of the cut and station 

(Table 5.21-2). For segment No. 1, adjacent to the yard and Townsend Street, only 40 percent of 

the trucks are assumed to use City streets; the remainder are assumed to stay internal to the yard 

in conveying material to trains for disposal. For the remaining three segments, all material is 

assumed to be hauled by truck to the yard. This is a conservative assumption because rail may 

be used to directly haul almost all of the material from segments Nos 1 and 2 instead of only 60 

percent of No. 1. Trucks bringing construction materials are estimated to be ten percent of those 

removing excavated material. 
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5.21 CONSTRUCTION IMPACTS 5-193 

Table 5.21-2: Projected Construction Truck Volumes 

Construction Segment Excavation Volume 

(cu yd) 

Trucks/hr* 

(Round Trips) Minutes/Truck 

No. 1. Yard & Townsend St. 292,000** 1 42 

No. 2. Second St. to Terminal 999,000 16 3.8 

No. 3. Terminal 658,000 8 7.6 

No. 4. To end of Mission St. 487,000 6 10 

Total 2,436,000 31 1.9 

Notes: 

*Also includes trucks carrying construction materials to sites. 

**Reduced by 60% to account for rail hauling. 

 Source: Parsons Corporation, September 2003

Under these assumptions, it was estimated that a total of 31 construction truck round trips per 

hour would be required to haul the debris or bring in construction materials. But due to the 

phasing of the construction, with segments Nos. 1 and 4 potentially being constructed in parallel 

and segments Nos. 2 and 3 being constructed later, the maximum number of trucks that would be 

circulating would be 7 trucks/hour for Nos. 1 and 4 combined and 24 trucks/hour for Nos. 2 and 

3 combined. Since the process would be a continuous cycle in which trucks would be arriving 

and departing, it is projected that, on the average, there would be between 14 and 48 construction 

truck trips on the local street network during each operating hour. These trucks would be 

operating on several different streets and arriving or departing from several different construction 

sites, as listed above. However, under the assumption that most of the excavated material would 

be hauled away by train, all of the haul trucks would converge at Seventh and Townsend to load 

the spoil onto trains. 

5.21.2.2 Truck Routes

Delivery trips from the staging areas along the alignment are combined with the excavation 

removal. Truck routes by segment would be as follows: 

1. Yard and Townsend Street—Trucks will circulate from the yard to Seventh to Brannan to 

Fourth, Third, or Second and back to Townsend to yard. The volume will be 1 truck/hr. 

This pattern combines with No. 4 to give a total of 7 trucks per hour. 

2. Second to Terminal—Trucks will circulate up Seventh to Brannan to Third, cross over to 

Second and return down Second to Townsend to Seventh and yard. The volume will be 

16 trucks/hr. It is sequential to No. 1/No. 4 and parallel No. 3 to give 24 trucks per hour. 

3. Terminal—Trucks will circulate from the yard to Seventh to Bryant to Fremont to 

Terminal to Howard to Fourth to Townsend/Brannan to Seventh to yard. The volume 

will be 8 trucks/hr. This segment will be excavated at the same time as No. 2, giving a 

total of 24 trucks per hour. 

4. Terminal down Mission Street—Trucks will circulate from the yard down Seventh to 

Townsend to Embarcadero to Mission, returning via Embarcadero to Townsend to 
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5-194 5.21 CONSTRUCTION IMPACTS

Seventh to yard. The volume will be 6 trucks per hour, giving a total of 7 trucks per hour 

when combined with No. 1. 

Under this “worst case” analysis for the cut-and-cover option, all of the trucks would travel 

along Seventh Street, departing or returning to the Caltrain Fourth and Townsend yard. 

Because of the relatively low existing volumes on Seventh Street, 24 truck round trips per hour 

would not cause deterioration in the level of service on Seventh Street. The greatest impact 

under this worst case analysis would be 24 trucks per hour being added to Howard Street at 

Third Street, but that is only one percent or less of the P.M. peak hour movement. The 

assumption of eight haul hours per day allows for avoidance of peak periods between 7 a.m. and 

5 p.m., so the haul volumes can be scheduled outside the peak periods if necessary. Impacts 

under the LPA would be lower than this worst case cut-and-cover scenario. The next subsection 

analyzes the P.M. peak hour primary construction detour traffic with these haul movements 

superimposed. 

5.21.2.3 Detour for Second Street Closures 

For the Cut-and-Cover Option, Second Street would be closed to through traffic one block at a 

time between Townsend Street and Howard Street to facilitate construction of the cut-and-cover 

trench. Each block would be closed for an estimated month or two except for maintaining 

essential local access. See Subsection 5.21.2.5 for a discussion of access to driveways. 

During these rolling closures of the five blocks on Second Street between Townsend Street and 

Howard Street, through traffic would be detoured onto parallel streets, primarily Third and 

Fourth Streets. Third Street, currently one-way northbound, would be restriped to give three 

lanes northbound and two lanes southbound. On-street parking would be prohibited on Third 

Street for the duration of the detour. The bus lane on Third Street would become a mixed flow 

lane for the duration of the detour, although it also functions well as a combined bus/right-turn 

lane where there is a substantial number of right turns, such as at Harrison or Bryant Streets. 

The Third Street detour can be accomplished in two phases. During any closure of Second Street 

south of Harrison Street, the two-way portion of Third Street would be from Harrison Street to 

King Street. In this phase, Third Street could remain one-way northbound north of Harrison 

Street. During any closure of Second Street north of Harrison Street, the two-way portion of 

Third Street will be from Howard Street to King Street. It is anticipated that the cut-and-cover 

trench on Second Street would be constructed from south to north, starting at Townsend Street 

and going to Howard Street. 

During the closure of a block on Second Street, the two-way portion of Third Street would 

facilitate detouring traffic around the closed block. Because some of the cross streets are one 

way, through traffic would often be diverted for two blocks or more instead of around just one 

block. It is expected that much of the I-80 and I-280 traffic on Second Street would shift over to 

Fourth Street for the southbound portion of the detour and to Third Street for the northbound 

portion of the detour. The LPA would use cut-and-cover construction only between Folsom and 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5.21 CONSTRUCTION IMPACTS 5-195 

Howard streets, and the two-way portion of Third Street would be limited to just the portion 

between Folsom and Howard streets to accommodate the southbound traffic in the closed block. 

Northbound traffic would have to be detoured two blocks on Third Street, from Harrison Street 

to Howard Street, but would use the existing northbound lanes on Third Street. 

5.21.2.4 Intersection Analysis 

Key intersections for detour traffic conflicts include Third/Howard, Third/Harrison, and 

Fourth/Harrison. Table 5.21-3 summarizes LOS calculations under detour and truck haul 

conditions for each closed block compared with baseline conditions in 2005, the expected 

midpoint of construction. 

Table 5.21-3: Intersection Delay and LOS for Third Street Detour -- 2005 Conditions 

Intersection* 

Third/Howard 

Block Closed of 

Second Street Base Mitigated Third/Harrison Fourth/Harrison 

None LOS B B B 

 Delay 14.5 10 11.4 

Howard/Folsom** LOS E D D B 

 Delay 42.4 39.9 28.7 11.3 

Folsom/Harrison LOS E D D B 

 Delay 42.4 39.9 30 11.3 

Harrison/Bryant LOS B D+ B 

 Delay 14.5 26.4 11.7 

Bryant/Brannan LOS B D+ B 

 Delay 14.5 26.4 11.7 

Brannan/Townsend LOS B D+ B 

 Delay 14.5 26.4 11.7 

*Delay and level of service are based on 1994 Highway Capacity Manual (SIGNAL94). Delay is in seconds. 

**NB lanes consist of two through lanes and one RT/bus lane 

The intersection affected with the most diverted turning movements, Third/Howard, dropped 

from LOS B to E with a lane configuration of two northbound mixed flow lanes and one bus lane. 

Elimination of the bus lane to give three northbound mixed flow lanes and the addition of a left 

turn lane on Howard resulted in the projected LOS reaching LOS D. None of the other key 

intersections affected by the detour were projected to have impacts from the detour. 

5.21.2.5 Other Detour Routes 

Construction methods for the cut-and-cover tail track section of the Second-to-Mission 

Alternative would require that Mission Street be closed except for one lane in each direction 

with no parking for up to two years. As part of the construction phasing, Mission Street would 

have to be completely closed for an additional one to three months at both the start and finish of 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5-196 5.21 CONSTRUCTION IMPACTS

construction to put on a temporary deck and to restore the street surface. Cross streets of Beale, 

Main, and Stuart would also require closure to through traffic at staggered periods of one to 

three months. 

Similarly, construction methods for the cut-and-cover tail track section of the Second-to-Main 

Alternative would require that two lanes on Main Street be closed for up to two years. As part of 

the construction phasing, Main Street would have to be completely closed for an additional one 

to three months at both the start and finish of construction to put on a temporary deck and to 

restore the street surface. Cross streets of Folsom and Harrison would also require closure to 

through traffic at staggered periods of one to three months. 

The detours in street traffic for either of these alternatives would result in adverse effects on 

intersection operations at several intersections in the downtown area. The detours would last 

two years and would add vehicular traffic to already congested movements and/or create new 

demand for movements that conflict with other high demand movements. Affected intersections 

for the Second-to-Mission Alternative would include: 

• Beale/Howard 

• Main/Howard 

• Stuart/Howard 

• Howard/Embarcadero 

• Beale/Folsom 

• Main/Folsom 

• Folsom/Embarcadero 

Affected intersections for the Second-to-Main Alternative would include: 

• Embarcadero/Mission 

• Embarcadero/Howard 

• Embarcadero/Folsom 

• Embarcadero/Harrison 

5.21.2.6 Coordination with Third Street Light Rail/Central Subway 

Potential exists for conflict between the traffic detour plans of the Central Subway project and 

the Caltrain extension alternatives. Both the Cut-and-Cover Option and the Tunnel Option 

would close portions of Second Street to through traffic while Third Street would be designated 

as a primary detour route. In contrast, the Central Subway project would close portions of Third 

Street to through traffic and would designate Second Street as a primary detour route. The 

schedules for the two projects, however, show that the Caltrain LPA would largely, if not 

entirely, avoid this conflict. Based on the current schedule for construction of the LPA, Second 

Street would be closed between Folsom Street and Howard Street for about two years, reopening 

in mid 2009. The proposed detour for this closure is discussed at the end of Subsection 5.21.2.3 
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5.21 CONSTRUCTION IMPACTS 5-197 

above. The Central Subway project is currently scheduled to begin cur-and-cover station 

construction on Third Street between Folsom Street and Howard Street in mid 2009, avoiding 

the period when the LPA would use Third Street as a detour and when Second Street would not 

be available for the Central Subway detour. The Central Subway would have utility relocation 

activities that would precede the station construction, but the LPA schedule has potential to be 

accelerated to avoid conflict with those activities. The ISCOT Committee, an interdepartmental 

staff committee on Traffic and Transportation in the City and County of San Francisco, will be 

utilized to minimize or avoid the traffic detour conflicts between these two projects. 

5.21.2.7 Driveway Access 

The Second Street segment of the Second-to-Main and Second-to-Mission alternatives has the 

highest number of driveways that would be affected by cut-and-cover construction, and the 

following analysis represents a “worst-case” evaluation. The Tunneling Option for either 

Caltrain Downtown Extension alternative would have substantially fewer effects on driveways. 

Between Brannan and Howard Streets, there are 13 locations (i.e., parking lots, businesses, 

residents, etc.). In addition to these locations, four dead end streets cross Second Street at De 

Boom and Federal Streets, Dow Place, and Tehama Streets. These dead end streets provide 

access to numerous private parking lots, loading docks, and public parking. Easements would 

be required to maintain access at Tehama Street and Dow Place. Temporary alternative access 

would be acquired through private property between Federal and De Boom Streets. A list of 

driveways that would be affected by construction on Townsend, Second, Main, and Mission 

Streets is included in Table 5.21-4. 

Table 5.21-4: Driveways and Streets Temporary Blocked By Construction 

Street Segment Address Land Use Description 

Townsend Street (Both Caltrain Extension Alternatives – (Cut-and-Cover or Tunnel Option) 

Fifth to Fourth Street 310 Townsend Office Garage Entrance/Exit 

 306 Townsend Office Garage Entrance/Exit 

Fourth to Third Street 292, 294, 296 Townsend Retail Parking entrance for numerous businesses.

 290 Townsend Retail Loading Dock. 

 On southern side of Townsend Vacant/Under 

Construction 

Driveways to new mixed use 

development. 

Third Street to Clarence 

Place (Cut-and-Cover Option 

only) 

701 Third 

Food Townsend Street drive thru entrance and 

exit. 

 179 Third Office Garage and parking lot entrance and exit. 

 178 Third Parking Parking Garage Entrance. 

Second Street 

Brannan To Bryant 

 (Cut-and-Cover Option only) Brannan @ Second (northwest side) Vacant/Under 

Construction Delivery Entrance. 

South Park @ Second (southwest 

side) 

Vacant/Under 

Construction Delivery/Driveway Entrance. 
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5-198 5.21 CONSTRUCTION IMPACTS

Table 5.21-4: Driveways and Streets Temporary Blocked By Construction 

Street Segment Address Land Use Description 

577 Second Retail Driveway Entrance. 

522 and 524 Second Light Industrial Driveway Entrance. 

Bryant To Harrison 

 (Cut-and-Cover Option only) 461 Second Residential Driveway Entrance. 

 Underneath I-80 Freeway Parking Parking Lot Entrance/Exit. 

425 Second Residential Delivery Entrance/Exit. 

Not Available Parking Parking Lot Entrance/Exit. 

Second @ Harrison (southeast 

corner) 

Parking Parking Lot Entrance/Exit. 

Harrison To Folsom 

(Cut-and-cover Option only) On west side of Second Parking Parking Lot Entrance/Exit. 

Folsom To Howard (Cut-andCover or Tunneling Option) 

Folsom @ Second (northeast 

corner) 

Hotel Driveway of New Building. 

 246 Second Residential Driveway Entrance/Exit. 

Howard @ Second (southeast 

corner) 

Parking Parking Lot Entrance/Exit. 

Second-to-Main Alternative Only (Cut-and-Cover or Tunnel Option) 

Main Street 

Harrison To Folsom 365 Main Vacant/Under 

Construction Shipping/Receiving Driveways 

390 Main Public Services Parking Lot Entrance/Exit. 

 Folsom @ Main (southeast corner) Parking Parking Lot Entrance/Exit. 

Folsom To Howard 

 160 Folsom Retail Driveway Entrance on Main Street. 

 On east side of Main Parking Parking Lot Entrance/Exit. 

250 Main Transportation Three Parking Lot Entrances. 

 272 and 276 Main Office Parking Lot Entrance/Exit. 

 221 Main Office Underground Parking Lot Entrance/Exit. 

Second-to-Mission Alternative (Cut-and-Cover or Tunnel Option) 

Mission Street 

Main To Spear 77 Beale Office Driveway Exit. 

 110 Mission Office Parking Lot Entrance/Exit. 

At The Embarcadero On north side of Mission Parking Muni/Public Parking Entrance/Exit. 

Transbay Terminal Impacts 500 Mission Office Four Loading Docks on Minna Street. 

Loss of access to any property would be minimized via prompt construction of the roadway 

decks, first on one side and then the other. The construction contractor or construction 

representative would work with and notify property owners, businesses, and residents regarding 

the temporary loss of access. 

Prior to initiating construction of each segment, outreach efforts would be performed to inform 

residents, businesses, and property owners of the proposed construction program. A community 

construction coordination program would be established to encourage communication between 
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5.21 CONSTRUCTION IMPACTS 5-199 

the affected community, both residential and business, and the TJPA and JPB regarding 

construction impacts and possible mitigation and solutions. 

Prior to and during construction, the TJPA and JPB staff would contact and interview individual 

businesses and property owners potentially affected by construction activities. Interviews with 

commercial establishments would provide knowledge and understanding of how these businesses 

carry out their work, and identify business usage, delivery and shipping patterns and critical 

times of the day and year for business activities. Data gathered from these interviews would 

assist the JPTA and JPB as they work with the DPT to develop the worksite traffic control plans. 

Among other elements, these plans will identify alternate access routes to maintain critical 

business activities. 

The mitigation measures described in the following sections would be implemented by a 

combination of construction contract specifications, drawings, and provisions, as well as public 

affairs programs. TJPA and JPB staff would be assigned to work directly with the public to 

provide project information and to resolve construction-related problems. The TJPA and JPB 

will work with community residents, elected officials, local businesses, and community 

organizations to tailor the mitigation program to best meet community needs. Contractors will 

be monitored to assure that mitigation measures contained in the Final EIS/EIR are met. 

The TJPA and JPB would inform the public of its progress in implementing the measures 

selected through a quarterly program of auditing, monitoring, and reporting. A quarterly status 

report would be made available to the public. 

Site and Field Offices. During construction of the Terminal/Extension Project, TJPA and JPB 

staff would establish an information field office located along the alignment. The field office 

staff in conjunction with other staff would serve multiple purposes: 

• Provide the community and businesses with a physical location where information pertaining 

to construction can be exchanged, 

• Enable TJPA and JPB to better understand community/business needs during the 

construction period, 

• Allow TJPA and JPB to participate in local events in an effort to promote public awareness 

of the project, 

• Manage construction-related matters pertaining to the public, 

• Notify property owners, residences, and businesses of major construction activities (e.g., 

utility relocation/disruption and milestones, re-routing of delivery trucks), 

• Provide literature to the public and press, 

• Promote and provide presentations on the project via a Speakers Bureau, 

• Respond to phone inquires, 

• Coordinate business outreach programs, 

• Schedule promotional displays, and 

• Participate in community committees. 
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5-200 5.21 CONSTRUCTION IMPACTS

The information office would be open various days of the work week for the duration of the 

construction period. A schedule will be developed before construction begins. 

Information Line. A telephone information line would be available to provide community 

members and businesses the opportunity to express their views regarding construction. Calls 

received would be reviewed by TJPA and JPB staff and would, as appropriate, be forwarded to 

the necessary party for action (e.g., utility company, fire department, the Resident Engineer in 

charge of construction operations). Information available from the telephone line would include 

current project schedule, dates for upcoming community meetings, notice of construction 

impacts, individual problem solving, construction complaints and general information. During 

construction of the project, phone service would be provided in English, Cantonese, and Spanish 

and would be operated on a 24-hour basis. 

Signage. The TJPA and JPB would work with establishments affected by construction activities. 

Appropriate signage would be developed and displayed to direct both pedestrian and vehicular 

traffic to businesses via alternate routes. 

Traffic Management Plans. Traffic management plans to maintain access to all businesses 

would be prepared for areas affected by surface or cut-and-cover construction. In addition, daily 

cleaning of work areas would be performed by contractors for the duration of the construction 

period. Provisions would be contained in construction contracts to require the maintenance of 

driveway access to businesses to the extent feasible. 

Deck Level. Decking at the under-street cut-and-cover sections would be installed flush with the 

existing street or sidewalk levels. 

Sidewalk Design and Maintenance. Wherever feasible, sidewalks would be maintained at the 

existing width during construction. Where a sidewalk must be temporarily narrowed during 

construction (e.g., deck installation), it would be restored to its original width during the majority 

of construction period. In some places this may require placing the temporary sidewalk actually 

on the deck. Each sidewalk design should be of good quality and approved by the Resident 

Engineer prior to construction. Handicapped access would be maintained during construction 

where feasible. 

Construction Site Fencing. Construction site fencing should be of good quality, capable of 

supporting the accidental application of the weight of an adult without collapse or major 

deformation. Fence designs or examples would be submitted to the Resident Engineer for 

approval prior to installation. Where covered walkways or other solid surface fencing is 

installed, a program will be implemented to allow for art work (e.g., by local students) on the 

surface(s). 
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5.21 CONSTRUCTION IMPACTS 5-201 

5.21.3 PARKING

On-street parking would be temporarily removed along specific streets for a set amount of time 

during construction. Under the Cut-and-Cover Option, parking on Second Street would be 

closed and re-opened on a block-by-block basis due to construction. To mitigate the closure of 

Second Street, traffic would need to detour to Third Street. When Second Street is closed south 

of Harrison, no parking would be allowed on Third between Harrison and King Streets. When 

Second Street is closed north of Harrison, no parking would be allowed on Third between 

Howard and King Streets. See Section 5.21.2.3 for details of the Second Street detour. The 

contractor would post dates and times of parking closures and openings. Loss of parking could 

affect local businesses, as discussed in Section 5.21.2.5. Table 5.21-5 includes segments where 

on-street parking would be temporarily removed during construction and the number of 

temporarily removed parking spaces removed is also shown. 

The Caltrain ridership forecast did not assume parking capacity expansion at any stations that 

had reached parking capacity under the 2020 No-Project conditions. Therefore, there are no 

long-term adverse impacts to parking projected for Caltrain stations as a result of the 

Terminal/Extension Project. 

Table 5.21-5: On-Street Parking Removed During Construction 

Second-to-Main and 

Second-to-Mission Alternatives Direction of On-Street Parking 

Townsend Street Eastbound Westbound 

 Fifth to Fourth Street Diagonal parking Perpendicular parking 

 Fourth to Third Street No parking (construction zone) Parallel parking

 Third Street to Clarence Place Parallel parking Parallel parking 

Second Street Northbound Southbound 

 Brannan to Bryant Parallel parking, 11 auto spaces Parallel parking, 10 auto spaces 

 Bryant to Harrison Parallel parking, 9 auto spaces Parallel parking, 10 auto spaces

 Harrison to Folsom Parallel parking, 17 auto and 4 

motorcycle spaces 

Parallel parking, 15 auto spaces

 Folsom to Howard Parallel parking, 12 auto spaces Parallel parking, 11 auto spaces 

Third Street Northbound Southbound 

 King to Townsend Parallel parking, 13 auto spaces Parallel parking, 13 auto spaces 

 Townsend to Brannan Parallel parking, 21 auto spaces Parallel parking, 23 auto spaces 

 Brannan to Bryant Parallel parking, 3 auto spaces Parallel parking, 23 auto spaces 

 Bryant to Harrison Parallel parking, 11 auto spaces Parallel parking, 11 auto spaces 

 Harrison to Folsom Parallel parking, 18 auto spaces Parallel parking, 25 auto spaces 

 Folsom to Howard No parking No parking 

Second-to-Main Alternative Northbound Southbound 

 Midway from Bryant to Howard Parallel parking Parallel parking 

Second-to-Mission Alternative Eastbound Westbound 

 Main to Spear Parallel parking Parallel parking 

 Spear to Steuart Parallel parking Parallel parking 

 Steuart to The Embarcadero Parallel parking No parking 
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5-202 5.21 CONSTRUCTION IMPACTS

5.21.4 PEDESTRIANS 

Before construction of the Transbay Terminal/Extension Project begins, two one-story temporary 

terminals would be built. A terminal for AC Transit buses would be located on the block 

bounded by Beale/Howard/Main/Folsom Streets, and a terminal for Greyhound buses would be 

located on Folsom Street between Fremont and Beale Streets. Temporary bus terminals would 

be located contiguous to the P.M. casual carpool queuing area. Because the temporary terminals 

would disrupt this queue activity, the casual carpool queues would be moved to the west side of 

Beale Street. 

The temporary AC Transit terminal would be located two blocks east and one block south of the 

existing terminal, while the Greyhound terminal would be located one block east and one block 

south of the existing Transbay Terminal. The existing (2000) pedestrian travel patterns to and 

from the Transbay Terminal as determined by the SFTA model indicate that 70 percent of 

pedestrians going to and from the terminal would have up to a four block longer walk than under 

the existing situation. An additional 22 percent would have to walk up to three additional blocks 

to reach the terminal, while 4 percent would have to walk about one additional block to reach the 

terminal. About four percent of pedestrian walk distances would not be affected or would be 

shorter. For those with up to a four block additional walk, this represents about 800 additional 

feet of travel distance. At a pedestrian pace of 200 feet per minute, the additional 4-block walk 

is estimated to take four minutes. 

5.21.5 BICYCLES

The temporary relocation of the Transbay Terminal during construction would increase bike 

travel distance to the terminal for the majority of bicyclists. The distance would increase by up 

to four blocks, which would add about two additional minutes of bicycle travel time. No 

mitigation measures are proposed other than that bicycles would be allowed to use temporary 

street improvements made for transit. 

5.21.6 NEIGHBORHOODS AND BUSINESSES

In general, business and residential impacts would include changes in traffic circulation 

attributable to street closures, some loss of on-street parking, increased truck as well as auto 

traffic on designated haul routes and detours, increased noise in the vicinity of surface 

construction, and views obstructed or worsened by construction activity. 

The most substantial construction-phase effects on neighborhoods and businesses would occur 

on the four streets affected by the Cut-and-cover Option of both Caltrain Downtown Extension 

Alternatives. The disruption of residents and businesses during construction is an important 
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5.21 CONSTRUCTION IMPACTS 5-203 

concern of the TJPA and JPB. Measures would be incorporated in the construction program to 

minimize impacts to residents and businesses. 

Impacts to Residential Areas. Although most land uses along affected streets are commercial 

uses, there are some live/work lofts along Townsend Street and additional residential uses along 

Second Street, including live/work units at the Clock Tower Building, a residential building near 

Tehama Street, and the Courtyard Marriott hotel. During construction the residential uses would 

be subject to reduced vehicular access, increased traffic congestion, increased noise and 

construction-related dust. 

Impacts to Businesses. Most of the land uses along the Caltrain Downtown Extension 

Alternative alignments are commercial, and the majority of these commercial establishments 

consist of office uses. There are also retail uses, particularly on the ground floors of buildings 

along each of the affected streets, and there are warehouse and light-industrial uses on Second 

and Townsend Streets. Cut-and-cover construction effects on businesses would include reduced 

vehicular access and increased traffic congestion, increased noise and debris, and decreased 

visibility of operating businesses. These disruptions would most likely have the greatest impact 

on the retail establishments, many of which rely more heavily on walk-in traffic and street 

visibility for sales activity than office uses and warehouse businesses also located in these areas. 

There is a potential reduction in the ability of large trucks to access warehouse and storage 

facilities. 

The Muni Metro Turnback Project in downtown San Francisco serves as a meaningful case study 

from which to predict how businesses would be affected by project construction. During 

construction of the Muni Metro Project, businesses located along The Embarcadero – fronting 

the cut-and-cover construction of the project – experienced partial or complete loss of visibility 

and access. Where possible, these businesses reoriented themselves to Steuart Street. Several 

hotel and restaurant owners whose businesses were affected by severe noise and debris were 

successful in negotiating to cease all construction activity between 12:30 and 1:30 p.m. daily, in 

order to allow for more comfortable lunch hour operations. One small delicatessen, which lost 

all visibility due to construction fences that were assembled around the project, was offered 

reduced rent by the building owner for the duration of construction to offset sales losses. 

The loss of on-street parking spaces also raises issues related to economic impacts. Several 

blocks of unmetered parallel parking spaces would be temporarily lost along Townsend Street 

during construction of the Townsend alignment, potentially exacerbating difficult conditions for 

local business owners, particularly the small retailers. 
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5-204 5.21 CONSTRUCTION IMPACTS

Prior to initiating construction on major elements of the Terminal/Extension Project, outreach 

efforts would be performed to inform residents, businesses, and property owners of the proposed 

construction program. A community construction coordination program as described above in 

Section 5.21.2.5 would be established to encourage communication between the affected 

community, both residential and business, and the TJPA and JPB regarding construction impacts 

and possible mitigation and solutions. 

5.21.7 COMMUNITY FACILITIES AND SERVICES

None of the community facilities identified in Section 4.3 would be affected by construction 

activities, except to the extent that traffic delays caused by temporary detours and congestion 

may inconvenience persons gaining access to these facilities. 

Safety and security services during construction would be provided by the San Francisco Police 

Department and other security personnel identified in Sections 4.3 and 5.17. The San Francisco 

Police Department would likely assign officers to monitor traffic congestion and detours along 

surface streets during construction. It is likely that existing officers would be assigned to this 

task, and at this time no additional costs to the Department are anticipated. While emergency 

access would potentially be affected by any change in traffic conditions in the area, the traffic 

impacts of the project would be very minor and should not affect emergency response times. 

The Fire Department would review project plans at time of permitting to ensure that adequate 

life safety measures and emergency access are provided during construction of the 

Terminal/Extension Project. To reduce the potential for impacts to occur a life safety plan would 

be developed and implemented, as described in Section 5.4. 

The City’s Solid Waste Management Program has indicated that the amount of construction 

debris generated and disposed of could be adequately accommodated by existing landfills (Kevin 

Drew, Solid Waste Management Program Associate, responses to questionnaire, June 13, 2001). 

Mitigation measures are identified in Section 5.21.6.2, however, in order to help San Francisco 

achieve the 50 percent reduction goal specified in the California Integrated Solid Waste 

Management Act of 1989 (AB 939). In addition, the Terminal/Extension Project would comply 

with all City and County ordinances regarding the minimization of waste though recycling. 

To reduce the short-term solid waste impacts associated with construction, the construction 

specifications will require the use recycled construction materials where feasible, and will 

include specification regarding the recycling of construction and demolition materials. 
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5.21 CONSTRUCTION IMPACTS 5-205 

5.21.8 PARKLANDS, SCHOOLS, AND CHURCHES

None of the parks, schools, or churches identified in Section 4.4 would be affected by 

construction activities, except to the extent that traffic delays caused by temporary detours and 

congestion may inconvenience persons gaining access to these facilities. 

5.21.9 AIR QUALITY

Construction activities can cause pollutant emissions in a number of ways, including emissions 

of nitrogen oxides, carbon monoxide, and sulfur oxides from diesel-powered construction 

equipment; carbon monoxide emissions from worker vehicles; dust or PM10 emissions from 

vehicles traveling on unpaved surfaces and/or grading and other earthmoving activities; and 

reactive organic gas emissions from asphalt placement and architectural coatings. There are no 

quantitative emissions thresholds for construction activities, which are by their nature temporary 

and occur over a large area, potentially affecting different receptors at different times. The Bay 

Area Air Quality Management District’s (BAAQMD) approach to the analysis of construction 

impacts is to emphasize implementation of effective and comprehensive control measures rather 

than detailed quantification of emissions. 

Specific construction practices can minimize or control certain emissions, and the following 

mitigation measures, which are derived from the "basic control measures" and the "enhanced 

control measures" recommended by the BAAQMD, are proposed as part of the project. 

As part of the contract provisions, the project contractor would be required to implement the 

following measures at all project construction sites: 

• Water all active construction areas at least twice daily. Ordinance 175-91, passed by the 

San Francisco Board of Supervisors on May 6, 1991, requires that non-potable water be 

used for dust control activities; therefore the project contractor would be required to 

obtain reclaimed water from the City's Clean Water Program or other appropriate 

sources. 

• Cover all trucks hauling soil, sand, and other loose materials or require all trucks to 

maintain at least two feet of freeboard. 

• Pave, apply water three times daily, or apply (non-toxic) soil stabilizers on all unpaved 

access roads, parking areas and staging areas at construction sites. 

• Sweep daily (with water sweepers) all paved access roads, parking areas and staging 

areas at construction sites. 

• Sweep streets daily (with water sweepers) if visible soil material is carried onto adjacent 

public streets. 

• Install sandbags or other erosion control measures to prevent silt runoff to public 

roadways. 

• Replant vegetation in disturbed areas as quickly as possible. 
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5-206 5.21 CONSTRUCTION IMPACTS

• Minimize use of on-site diesel construction equipment, particularly unnecessary idling. 

• Shut off construction equipment to reduce idling when not in direct use. 

• Where feasible, replace diesel equipment with electrically powered machinery. 

• Locate diesel engines, motors, or equipment as far away as possible from existing 

residential areas. 

• Properly tune and maintain all diesel power equipment. 

• Suspend grading operations during first and second stage smog alerts, and during high 

winds, i.e., greater than 25 miles per hour. 

Additionally, upon completion of the construction phase, buildings with visible signs of dirt and 

debris from the construction site shall be power washed and/or painted (given that permission is 

obtained from the property owner to gain access to and wash the property with no fee charged 

by the owner). 

5.21.10 CONSTRUCTION NOISE AND VIBRATION

5.21.10.1 Impacts 

Temporary intrusion from noise and vibration is associated with most large construction projects. 

Because of the short-term nature of the intrusion, construction noise and vibration are not usually 

considered impacts unless, as is the case for this project, the construction will last for an 

extended period of time. 

Construction noise varies greatly depending on the construction process, type and condition of 

equipment used, and layout of the construction site. Many of these factors are traditionally left 

to the contractor's discretion, which makes it difficult to accurately estimate levels of 

construction noise. The noise impact assessment for a construction site is based on: 

• An estimate of the type of equipment that will be used during each phase of the construction 

and the average daily duty cycle for each category of equipment, 

• Typical noise emission levels for each category of equipment, and 

• Estimates of noise attenuation as a function of distance from the construction site. 

Although the lack of specific information at the time of the environmental assessment makes 

estimates of construction noise approximate, the projections do provide a good picture of where 

noise impacts are likely to occur and the general types of noise mitigation that will be required to 

mitigate the impacts. 
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5.21 CONSTRUCTION IMPACTS 5-207 

Table 5.21-6 summarizes 

some of the available data on 

noise emissions of 

construction equipment from 

the FTA Guidance Manual. 

Shown are the average of the 

Lmax values at a distance of 

50 feet. Although the noise 

levels in the table represent 

typical values, there can be 

wide fluctuations in the noise 

emissions of similar 

equipment. In fact, several of 

the cited noise levels would 

exceed the limit in the San 

Francisco noise regulation 

that is discussed below. 

Construction noise at a given noise-sensitive location depends on the magnitude of noise during 

each construction phase, the duration of the noise, and the distance from the construction 

activities. Projecting construction noise requires a construction scenario of the equipment likely 

to be used and the average utilization factors or duty cycles (i.e., the percentage of time during 

operating hours that the equipment operates under full power during each phase). Using the 

typical sound emission characteristics, as given in Table 5.21-6, it is then possible to estimate Leq

or Ldn at various distances from the construction site. 

Table 5.21-7 is an example of the noise projections for equipment that is often used during cutand-cover subway construction. For the calculations it is assumed that all the equipment is 

located at the geometric center of the construction work site. Based on this scenario, a 12-hour 

Leq of 88 dBA should be expected at a distance of 50 feet from the geometric center of the work 

site. This is equivalent to an Leq of approximately 76 dBA at a distance of 200 feet from the 

construction site, significantly higher than the normal daytime Leq in the project area even in 

locations where ambient noise exposure is relatively high because of traffic on I-80. On cut-andcover construction, once roadway decking is in place over the excavated trench, most of the 

construction activities will be shielded by the decking material, resulting in substantially lower 

noise levels for buildings adjacent to the construction site. 

Table 5.21-6: Construction Equipment Noise Emission Levels 

Equipment Type Typical Sound Level at 50 ft (dBA) 

Backhoe 80 

Bulldozer 85 

Compactor 82 

Compressor 81 

Concrete Mixer 85 

Concrete Pump 82 

Crane, Derrick 88 

Crane, Mobile 83 

Generator 81 

Loader 85 

Pavement Breaker 88 

Paver 89 

Pile Driver, Impact 101 

Pump 76 

Roller 74 

Shovel 82 

Truck 88 

Source: Harris Miller Miller and Hanson, September 2001 
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5-208 5.21 CONSTRUCTION IMPACTS

Table 5.21-7: Typical Equipment List, Subway Excavation 

Equipment Item Typical Sound 

Level at 50 ft (dBA)

Equipment 

Utilization Factor (%) Leq (dBA) 

Air Compressor 81 50% 78 

Backhoe 80 40% 76 

Crane, Derrick 88 10% 78 

Dozer 85 40% 81 

Generator 81 80% 80 

Loader 85 40% 81 

Pavement Breaker 88 4% 74 

Shovel 82 40% 78 

Dump Truck 88 16% 80 

Total workday Leq at 50 feet (12-hour workday) 89 

Source: Harris Miller Miller and Hanson, September 2001 

The construction phases of this project and the potential for noise and vibration impacts are 

summarized below: 

Utility Relocation: Relocating the utilities that conflict with the construction would not have 

much potential for noise impact. The equipment used is typical of normal street work. This 

construction would not normally warrant nighttime construction except in areas where the 

relocation efforts would cause unacceptable interference with traffic. 

Demolition: A number of buildings along the corridor would be demolished in preparation for 

cut-and-cover construction. No residential receptors are located near any of the buildings likely 

to be removed on Townsend Street. During the demolition of the Transbay Terminal, noise from 

impact equipment such as jackhammers, pavement breakers, and hoe rams could be disturbing to 

occupants of buildings near the Transbay Terminal. The land uses closest to the Transbay 

Terminal are primarily commercial and office space. Impacts on these spaces would be 

temporary and would not disrupt normal use of the buildings. 

The other major demolition effort would be removing the existing bus ramps leading from the 

current western exit of the Transbay Terminal. Again, the impact equipment used in the 

demolition is the most likely to cause intrusive noise. The land uses closest to the ramps are 

primarily commercial and office space. Impacts on these spaces would be temporary, typically a 

month or two while the nearest ramp is being demolished, and would not disrupt normal use of 

the buildings. 

Surface Rail Line and Station Construction: Surface rail line and station construction would 

primarily affect buildings along Townsend Street from Seventh Street to the subway portal. 

Existing land uses are primarily commercial, industrial or office space with some mixed-use 

residential buildings along Townsend Street west of Fourth Street. Noise from daytime 

construction, particularly pile driving, may be intrusive on an intermittent basis, however, 

compliance with the limits of the San Francisco noise regulations would avoid significant noise 
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5.21 CONSTRUCTION IMPACTS 5-209 

impacts. Nighttime construction could result in noise impacts to mixed-use residential buildings 

within a block of Townsend Street. 

Retained Cut/Portal Construction: The construction of the retained cut and the portal would 

include drilling a number of auger holes to build the soil-cement walls, excavation between the 

walls, and construction of the track bed and track. The land uses most affected by the 

construction would be along Townsend Street, which is primarily commercial and industrial with 

some office space. Some nighttime construction might be advantageous to avoid disruptions 

during normal business hours, but could result in noise impacts to mixed-use residential 

buildings within the blocks of Townsend Street to the west of Fourth Street. 

 

Tunnel Construction and Street Reconstruction: This section addresses noise and vibration 

impacts of subway construction. The subway track sections between Townsend Street and the 

Transbay Terminal and on down Main Street or Mission Street would be constructed using cutand-cover construction, or a combination of cut-and-cover and stacked-drift construction 

methods (to tunnel the portion of the alignment from Townsend Street to Folsom Street). It is 

anticipated that subway construction would last for a total period of approximately three and a 

half to four years, with up to 36 months required for the stacked-drift tunnel portion. 

Cut-and-Cover Construction. The noisiest phases of cut-and-cover construction are the initial 

construction of the support walls and installation of the roadway decking. To minimize traffic 

disruption during installation of decking where the alignment passes under Beale Street, First 

Street and Fremont Street, some construction would be done during nighttime hours with 

trenches covered to allow normal traffic flow during the daytime. This nighttime construction 

would not cause noise impacts since there are no residential land uses in these areas. Once the 

decking is in place for cut-and-cover construction, excavation and construction would continue 

under the decking. During the excavation and bracing phases, above-ground activities would 

consist primarily of cranes removing excavated material and trucks hauling the excavated 

material away. Surface activities would not be a major factor for the remainder of cut-and-cover 

construction with the exception of street reconstruction at the very end of the project. 

Vibration impacts from cut-and-cover construction methods would result primarily from the use 

of impact equipment such as hoe-rams. These impacts would be expected to produce some 

short-term annoyance exceeding frequent event criterion levels of 72 VdB throughout the 

duration of the cut-and-cover construction; mitigation measures are proposed. Impacts 

exceeding the damage criterion level are not anticipated. 

Stacked-drift Tunneling. Construction machinery used for the stacked-drift tunneling method 

would include tracked vehicles, excavation equipment, and vibratory compactors. No noise 

impacts of stacked-drift tunneling are anticipated because land uses at the surface would be 

shielded from construction activities. The vibration produced by tunneling equipment would, 

however, be of sufficient magnitude to be perceptible and annoying at times for the occupants of 

residences closest to the construction. Exceedences of the frequent event criterion of 72VdB are 
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5-210 5.21 CONSTRUCTION IMPACTS

expected to be even greater than with cut-and-cover construction. Mitigation measures are 

identified. 

Vibration Effects on Historic Buildings. Because vibration from construction activities and 

equipment can be of sufficient magnitude to damage fragile historic buildings, a special study 

was done to determine whether vibration impacts of the project would exceed criteria levels for 

such sensitive land uses. These criteria are listed in Table 5.21-8. 

Table 5.21-8: Construction Vibration Impact Criteria 

Level of Impact Land Use Vibration Criterion, PPV 

(in.sec) 

Threshold of Potential (Cosmetic) Damage Fragile, Historic Structures 0.5 

Threshold of Minor Structural Damage Fragile, Historic Structures 0.3 

Threshold of Potential (Cosmetic) Damage Non-Fragile Structures 0.2 

Threshold of Minor Structural Damage Non-Fragile Structures 0.12 

Source: FTA 

Based on the study, no damage from construction vibration is anticipated at any of the buildings 

in this area from typical construction methods. Comparing the highest anticipated construction 

vibration levels to these criteria confirms that anticipated construction activities would not be 

sufficient to cause structural damage, even to the most fragile historic structures. 

Controlled Detonation. Controlled detonation may be required during tunnel construction 

through rock for both the cut-and-cover and stacked-drift construction methods, subject to 

additional geotechnical investigations and other considerations that would be determined during 

the final design and construction phases of the project. Any use of controlled detonation would 

be closely controlled and monitored to avoid damage to existing structures. Specific limits, 

practices, and monitoring and reporting procedures would be included within the contract 

documents to ensure that such construction methods, if used, would not exceed safety criteria. 

Contractor Work Areas: The specific construction activities that would occur at these sites 

would vary, depending on their location, however, there would be a considerable amount of 

heavy equipment operations at the sites. These sites would be the proposed locations for 

removal of much of the excavated material from retained cut, cut-and-cover, and stacked-drift 

tunnel construction. Activities would include temporary muck storage, muck removal, trucks 

transporting material to the construction site, cranes lowering and lifting materials from the 

access shafts, heavy equipment such as front end loaders, ready-mix trucks delivering concrete to 

the job, and tunnel ventilation equipment. The six contractor staging/work areas being 

considered for cut-and-cover construction are: 
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5.21 CONSTRUCTION IMPACTS 5-211 

1. East of Seventh Street, between Berry and Townsend Streets. This site is sufficiently 

removed from noise-sensitive receptors that the contractor would not have problems 

complying with the San Francisco noise regulations. 

2. North of Townsend Street, between Clarence Place and Stanford Street. This would be 

the staging area for the demolition of buildings at the southern end of the cut-and-cover 

tunnel section. There are no noise-sensitive locations near this area. 

3. Southwest corner of the intersection of Second and Brannan Streets. This site is located 

within 600 feet of multiple residences, however, several large buildings stand between 

the staging area and sensitive receptors. These buildings would provide adequate 

shielding between this staging area and nearby noise sensitive sites. 

4. Northeast corner of the intersection at Howard Street and Second Street. This site is 

located within 500 feet of the apartment building at 246 Second Street and the Marriott 

Hotel along Second Street. Based on preliminary calculations, the Leq over an 8-hour 

shift would be approximately 69 dBA at the apartment building. An Leq of 57 dBA was 

measured at these residences for a one-hour period during the evening commute period. 

It is estimated that the 24-hour noise exposure is about 60 dBA. 

Depending on the layout of the construction site and the specific equipment used during 

nighttime hours, meeting the nighttime noise limit in the San Francisco noise regulations 

of ambient plus 5 dBA is likely to require 7 to 10 dBA of noise reduction. Because of the 

elevation of the high-rise apartments, a sound wall around the perimeter of the site would 

provide mitigation only for residents on the lower floors. It is expected that the 

contractor will work with the San Francisco Department of Public Works (DPW) to avoid 

noise impacts to the closest residences. 

5. Parking lot on Main Street between Howard Street and Mission Street. There are no 

noise-sensitive land uses near this area. 

6. The parking lot west of Main Street between Howard and Mission Streets. This site is 

sufficiently removed from noise-sensitive receptors that the contractor would not have 

problems complying with the San Francisco noise regulations. 

Haul Routes: Deliveries to the construction sites and excavated material from the project will 

be moved along pre-selected haul routes. Most of the routes are along relatively busy streets 

with primarily commercial and industrial land uses. There are some intermixed office space and 

residential land uses along several of the planned haul routes. Because of the relatively high 

volumes of existing traffic on the haul routes during the daytime, the addition of construction 

trucks would not increase total traffic volumes to the extent that they would increase overall 

noise to levels that would create noise impacts at sensitive receptors along the routes. At 

nighttime, when existing traffic volumes are lower than during the day, the addition of 

construction trucks could influence traffic volumes to the extent that noise impacts would occur 
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5-212 5.21 CONSTRUCTION IMPACTS

in the following areas: Fourth Street, one block on Howard Street, and Brannan Street near 

Fourth Street. 

5.21.10.2 Mitigation Measures 

Noise: The following mitigation measures are proposed to reduce construction noise impacts: 

1. Comply with the San Francisco Noise Ordinance. The noise ordinance includes specific 

limits on noise from construction. The basic requirements are: 

• Maximum noise level from any piece of powered construction equipment is limited to 

80 dBA at 100 ft. This translates to 86 dBA at 50 feet. 

• Impact tools are exempted, although such equipment must be equipped with effective 

mufflers and shields. The noise control equipment on impact tools must be as 

recommended by the manufacturer and approved by the Director of Public Works. 

• Construction activity is prohibited between 8 p.m. and 7 a.m. if it causes noise that 

exceeds the ambient noise plus 5 dBA. 

The noise ordinance is enforced by the San Francisco DPW, which may waive some of 

the noise requirements to expedite the project or minimize traffic impacts. For example, 

along Townsend Street where much of the land use is commercial, business owners may 

prefer nighttime construction since it would reduce disruption during normal business 

hours. The DPW waivers usually allow most construction processes to continue until 2 

a.m., although construction processes that involve impacts are rarely allowed to extend 

beyond 10 p.m. This category would include equipment used in demolition such as 

jackhammers and hoe rams, and pile driving. 

It is not anticipated that the construction documents would have specific limits on 

nighttime construction. There may be times when nighttime construction is desirable 

(e.g., in commercial districts where nighttime construction would be less disruptive to 

businesses in the area) or necessary to avoid unacceptable traffic disruptions. Since the 

construction would be subject to the requirements of the San Francisco noise regulations, 

in these cases, the contractor would need to work with the DPW to come up with an 

acceptable approach balancing interruption of the business and residential community, 

traffic disruptions, and reducing the total duration of the construction. 

2. Conduct Noise Monitoring. The purpose of monitoring is to ensure that contractors take 

all reasonable steps to minimize noise. 

3. Conduct Inspections and Noise Testing of Equipment. This measure will ensure that all 

equipment on the site is in good condition and effectively muffled 

4. Implement an Active Community Liaison Program. This program would keep residents 

informed about construction plans so they can plan around periods of particularly high 
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5.21 CONSTRUCTION IMPACTS 5-213 

noise levels and would provide a conduit for residents to express any concerns or 

complaints about noise. 

5. Minimize the Use of Vehicle Backup Alarms. A particular concern is for backup alarms 

on construction vehicles operating during nighttime hours. Because backup alarms are 

designed to get people's attention, the sound can be very noticeable even when their 

sound level does not exceed the ambient, and it is common for backup alarms at 

construction sites to be major sources of noise complaints. A common approach to 

minimizing the use of backup alarms is to design the construction site with a circular 

flow pattern that minimizes backing up of trucks and other heavy equipment. Another 

approach to reducing the intrusion of backup alarms is to require all equipment on the site 

to be equipped with ambient sensitive alarms. With this type of alarm, the alarm sound is 

automatically adjusted based on the ambient noise. In nighttime hours when ambient 

noise is low, the backup alarm is adjusted down. 

6. Include Noise Control Requirements in Construction Specifications. These should 

require the contractor to: 

• Perform all construction in a manner to minimize noise. The contractor should be 

required to select construction processes and techniques that create the lowest noise 

levels. Examples are using predrilled piles instead of impact pile driving, mixing 

concrete offsite instead of onsite, and using hydraulic tools instead of pneumatic 

impact tools. 

• Use equipment with effective mufflers. Diesel motors are often the major noise 

source on construction sites. Contractors should be required to employ equipment 

fitted with the most effective commercially available mufflers. 

• Perform construction in a manner to maintain noise levels at noise sensitive land uses 

below specific limits. 

• Perform noise monitoring to demonstrate compliance with the noise limits. 

Independent noise monitoring should be performed to check compliance in 

particularly sensitive areas. 

• Minimize construction activities during evening, nighttime, weekend and holiday 

periods. Permits would be required before construction can be performed in noise 

sensitive areas during these periods. 

• Select haul routes that minimize intrusion to residential areas. This is particularly 

important for the trench alternatives that will require hauling large quantities of 

excavation material to disposal sites. 

7. Controlling noise in contractor work areas during nighttime hours is likely to require 

some mixture of the following approaches: 

• Restrictions on noise producing activities during nighttime hours. 
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5-214 5.21 CONSTRUCTION IMPACTS

• Laying out the site to keep noise producing activities as far as possible from 

residences, to minimize the use of backup alarms, and to minimize truck activity and 

truck queuing near the residential areas. 

• Use of procedures and equipment that produce lower noise levels than normal. For 

example, some manufacturers of construction equipment can supply special noise 

control kits with highly effective mufflers and other materials that substantially 

reduce noise emissions of equipment such as generators, tunnel ventilation 

equipment, and heavy diesel power equipment including mobile cranes and front-end 

loaders. 

• Use of temporary barriers near noisy activities. By locating the barriers close enough 

to the noise source, it is possible to obtain substantial noise attenuation with barriers 

10 to 12 feet high even though the residences are 30 to 40 feet higher than the 

construction site. 

• Use of partial enclosures around noisy activities. It is sometimes necessary to 

construct shed-like structures or complete buildings to contain the noise from 

nighttime activities. 

Vibration: The following procedures will be used to minimize the potential for annoyance or 

damage from construction vibration: 

1. Limit or prohibit use of construction techniques that create high vibration levels. At a 

minimum, processes such as pile driving would be prohibited at distances less than 250 

feet from residences. 

2. Restrict procedures that contractors can use in vibration sensitive areas. It is often 

possible to employ alternative techniques that create lower vibration levels. For example, 

unrestricted pile driving is one activity that has considerable potential for causing 

annoying vibration. Using the cast-in-drilled-hole piling method instead will eliminate 

most potential for vibration impact from the piling. 

3. Require vibration monitoring during vibration intensive activities. 

4. Restrict the hours of vibration intensive activities such as pile driving to weekdays during 

daytime hours. 

5. If resident annoyance from vibration becomes a problem, alternative construction 

methods and practices would be investigated in coordination with the construction 

contractor to reduce the impacts. 

6. Include specific limits, practices and monitoring and reporting procedures for the use of 

controlled detonation, if this construction technique is determined to be necessary. 
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5.21 CONSTRUCTION IMPACTS 5-215 

5.21.11 WATER RESOURCES

Construction grading, tunneling, and utility excavations would increase the sediment load to 

storm sewers during rainfall events. Sediment sources created during construction include soil 

stockpiles; soil tracked across construction areas, staging areas, and public roads; and soil 

transported to these areas by wind. Because stormwater in the study area discharges to the City’s 

combined storm/sanitary sewer system, sediment transported by stormwater would not affect 

surface water bodies in the project area (China Basin and San Francisco Bay). However, windtransported soils could contain contaminants that would affect nearby surface waters. 

Construction dewatering would locally result in the temporary lowering of the water table and 

could promote the downward migration of contaminants from the uppermost groundwater zone 

to deeper groundwater zones. If dewatering lowers the water table in areas where free-phase 

petroleum hydrocarbons are floating on the water table, the resulting decrease in the water-table 

elevation would smear the hydrocarbons across soils that otherwise may be only minimally 

affected. The impacts associated with handling and disposal of contaminated dewatering 

effluent are further discussed in Section 5.21.14. 

Construction excavation spoils will be appropriately managed so as to minimize wind dispersion 

of potentially contaminated soil particles. Spoils management practices are to include covering 

stockpiles with plastic sheeting, periodically spraying water on exposed soil areas to suppress 

dust generation, and decontamination of vehicles prior to departure from construction and 

staging areas. 

As discussed in Section 5.21.15, construction dewatering would be performed in stages in order 

to minimize downward migration of contaminants in shallow groundwater. Dewatering effluent 

will be discharged to the sanitary sewer and, therefore, would not affect nearby surface waters. 

Chemical test results for groundwater samples along the alignment would be used to obtain a 

batch discharge permit from the San Francisco Department of Public Works and to evaluate 

requirements for treatment prior to discharge to the sanitary sewer. Effluent produced during the 

dewatering of excavations would be collected in onsite storage tanks and periodically screened 

for potential contamination to confirm the need for treatment prior to discharge. If necessary, 

treatment may include: 

I. Allowing sediment to settle out of the effluent in order to reduce elevated metals 

concentrations that can result from high quantities of suspended sediment; and/or 

II. Carbon filtering to remove fuel hydrocarbons and PAHs. 
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5-216 5.21 CONSTRUCTION IMPACTS

5.21.12 UTILITIES

Impacts to utilities for the overall project are discussed in Section 5.12. If necessary, disruptions 

to service during construction would be short-term and carefully scheduled with advance notice 

given to affected customers. 

5.21.13 ELECTROMAGNETIC FIELDS

There would be no electromagnetic field impacts associated with construction of the 

Terminal/Extension Project. 

5.21.14 HISTORICAL AND CULTURAL RESOURCES

5.21.14.1 Archaeological Resources 

Long-term impacts to archaeological resources that may exist within the project Area of Effects 

(APE) – including measures to be taken in the event of unanticipated discoveries during 

construction – are discussed in Section 5.14, Historic and Cultural Resources. 

If buried cultural materials are unearthed during construction, work in the vicinity of the find 

would be halted until a qualified archaeologist can assess their significance. If human remains 

are encountered during construction, State Health and Safety Code Section 7050.5 states that no 

further disturbance shall occur until the County Coroner has made the necessary findings as to 

origin and disposition pursuant to Public Resources Code 5097.88. In either instance, TJPA, 

JPB, the City and County of San Francisco, and the Redevelopment Agency would be 

immediately notified. Please see Section 5.14.2 for a more detailed discussion of archaeology 

mitigation measures. 

5.21.14.2 Historical Architectural Resources 

Project impacts on historical architectural resources within the project APE are described in 

Section 5.14, Historic and Cultural Resources. Section 5.14 also describes suggested mitigation 

measures for long-term impacts to these resources; actual mitigation measures will be 

determined in consultation with the State Historic Preservation Officer and the Advisory Council 

on Historic Preservation and reported in the Final EIS/EIR. 

A construction easement will be required into the southeast corner of the 166-178 Townsend 

Street property, which is a contributor to the significance of the Rincon Point / South Beach 

Historic Warehouse – Industrial District. To avoid impacts to the building during and following 

construction of the subway, it is proposed to underpin the building prior to initiation of 

construction activities. 
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5.21 CONSTRUCTION IMPACTS 5-217 

5.21.15 CONSTRUCTION HAZARDOUS MATERIALS IMPACTS 

Two main types of hazardous materials/wastes may cause construction impacts: those used in 

the construction process and those that would be encountered or generated during construction. 

Some hazardous materials, primarily fuels and motor oils, would be used during construction. 

Construction of aboveground facilities would also use paints and other cleaners or degreasers. While 

these are commonly used materials, they are considered hazardous materials (fuels, for example, are 

flammable) based on their physical properties, and improper handling could potentially endanger 

workers and the public and also could result in contamination of soil and/or water. 

Contact with contaminants in the study area could potentially have adverse effects on worker, 

public, and environmental health and safety. During project construction, workers could be 

exposed to soil and/or groundwater containing hazardous substances via direct contact (ingestion 

or dermal contact) with contaminated soil and groundwater or via airborne pathways (inhalation 

of vapors). The public and environment could be exposed to contaminants transported offsite 

during construction. The degree of hazard associated with these impacts on human or 

environmental receptors would be a function of the chemical properties, concentrations and 

volume of contaminants, nature and duration of construction activities, and contaminant 

migration pathways. However, the largest degree of potential exposure risk is with the 

construction worker. 

Construction activities such as excavation, installation of deep foundations, or site dewatering 

within existing contaminated areas could potentially increase the spread of contaminants to 

surface water and other groundwater zones along the proposed alignment. Disposal of 

contaminated soil would transport contaminants out of the study area as well. 

As noted in Section 4.17, a total of 37 regulatory agency lists were searched to identify listed 

facilities within the project area. For purposes of this analysis, the 41 identified hazardous 

materials sites in the study area have been classified into three categories: 

• Locations that would be directly affected by construction along the proposed extension 

alignments; 

• Locations adjacent to or near the proposed project alignments that could be affected by 

project construction or that could provide sources of contaminants to the construction 

areas; and, 

• Properties with essentially no anticipated adverse impacts due to the distance from the 

proposed construction areas and nature of contamination. 

Table 5.21-9 presents a breakdown of the identified sites into these categories. 
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5-218 5.21 CONSTRUCTION IMPACTS

Storage Yard Area. Most of the identified hazardous materials sites located near the proposed 

storage yard are included on agency lists due to releases from underground storage tanks (USTs). 

According to the agencies’ information, the types of petroleum hydrocarbons that have been 

released from USTs near the proposed storage yards and surface tracks include diesel fuel, 

gasoline, motor oil, and various fuel oils. 

Construction of the storage yard and trenching for the alignment would result in disturbance of 

surface soils. None of the excavations are expected to be deep enough to encounter 

groundwater. Therefore, impacts to construction of the storage yard from UST releases would be 

limited to spoils handling and worker health and safety precautions for hydrocarboncontaminated soil. 

Because of their close proximity to the planned alignment, the following sites have the greatest 

likelihood to affect storage yard and track construction: 

• Southern Pacific Transportation, 329 Townsend Street, Site 30 

• Flair Electro Sales, 516 Townsend Street, Site 34 

Properties that are listed by the agencies to have remediation completed or deemed unnecessary 

are listed under the non-hazardous category. In addition to UST-related hydrocarbons, other 

potentially hazardous constituents that may affect yard and surface track construction include 

metals (primarily lead), PAHs, and VOCs (mainly solvents). PAHs and elevated concentrations 

of lead were detected during Embarcadero roadway-related investigations and construction along 

King Street (Site 32). Additionally, lead contamination is prevalent in fill material in the South 

of Market area (SOMA) and is likely to be encountered in fill disturbed by yard and track 

construction. Although coal tar has not been specifically identified in the storage yard and 

surface track area, PAHs associated with coal tar residues and other past land uses may be 

encountered in the fill. 

Townsend Street Cut-and-Cover Area. Two identified sites, Sun Chemical Corporation No. 1 

(Site 24) and the San Francisco Iron Foundry (Site 26), lie in or adjacent to the Townsend Street 

cut-and-cover subway segment. The Sun Chemical Corporation site is listed as requiring no 

further action by the California Department of Toxic Substances Control (DTSC). No 

information was available in the agencies’ databases regarding the nature of contamination at the 

San Francisco Iron Foundry site. However, based on the type of industry implied by the site 

name, it is reasonable to expect that soils at that site may contain elevated metals concentrations. 
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5.21 CONSTRUCTION IMPACTS 5-219 

Table 5.21-9: Classification of Potential Hazards Associated with Hazardous Materials Sites 

Potential Construction-Related 

Site No[1] Site Name and Location Hazard 

None [2] Indirect [3] Direct [4] 

1 Federal Reserve Bank, SE Corner of Mission and Main Streets X 

2 Talco Inc., 621 First Street X 

3 San Francisco Gas & Light Co., 401 Howard Street X[5] 

4 Caltrans (Transbay Terminal), 150 First Street X 

5 San Francisco Gas Light Co., 166 Fremont Street, 498 Howard Street X 

6 U.S. Marine Corps – Supply Depot, 160 Harrison Street X 

7 524 Howard Street HOA X 

8 Transportation the Department, 434 Main St X 

9 Caltrans, 120 Richards Street X 

10 Dahl Beck Electric Co., 580 Howard Street X 

11 141 New Montgomery, 171 New Montgomery Street X 

12 Oriental Warehouse X 

13 Unspecified Site, Second and Townsend Streets X 

14 Pacific Bell, 611 Folsom Street X 

15 600 Harrison Street X 

16 Photosynthesis LTD Chromeworks, 425 Bryant Street X 

17 George Lithograph CO, 650 Second Street X 

18 San Francisco Fire Dept., 698 Second Street X 

19 Commercial Building, 35 Stanford Street X 

20 Commercial Building, 101 Townsend Street X 

21 San Francisco Gas & Electric Co., 120 King Street X 

22 Pacific Gas Improvement Co., 169 Townsend Street X 

23 McDonalds Corp., 701 Third Street X 

24 Sun Chemical Corporation No. 1, 252 Townsend Street X 

25 Unspecified (Embarcadero Roadway Project) X 

26 San Francisco Iron Foundry, 260 Townsend Street X 

27 Heublin, Inc., 601 Fourth Street X 

28 San Pacific Imports, 530 Brannan Street X 

29 Commercial Building, 542 Brannan Street X 

30 Southern Pacific Transportation, 329 Townsend Street X 

31 SF Newspaper Agency, 590 Brannan Street X 

32 Unspecified (Embarcadero Roadway Project) X 

33 California Poultry Company, 777 Brannan Street X 

34 Flair Electro Sales, 516 Townsend Street, X 

35 Independent Electric Supply, 550 Townsend Street X 

36 Baker/ Hamilton Building, 638 King Street X 

37 Baker/ Hamilton Properties, LLC, 650 King Street X 

38 Golden Gate Disposal Co., 900 7th Street X 

39 Former Southern Pacific Co., 415 Channel Street X 

40 Greyhound, Hooper/ Seventh Street X 

41 The Glidden Company, 1400 Seventh Street X 

Notes: 

[1] Site numbers correspond to site location numbers shown on Figure 4.17-1. 

[2] Sources of potential contamination are judged to be sufficiently far from proposed construction activities that environmental impacts are not anticipated. 

[3] Properties adjacent to proposed construction areas or properties where the presence of potential sources is not well defined relative to planned construction. 

[4] Properties where proposed construction may pass directly through areas of known contamination. 

[5] Contamination may extend beyond site boundaries into areas that would be directly affected by construction. 

Source: Dames & Moore, 1996
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5-220 5.21 CONSTRUCTION IMPACTS

No other identified hazardous materials sites located near the Townsend Street cut-and-cover 

tunnel section are expected to have affected soil that would be disturbed during construction of 

the Townsend Street segment. 

Several identified UST release locations (Sites 16, 27, 28, 29, and 31) may be located 

hydrogeologically upgradient of the cut-and-cover tunnel section; therefore, groundwater 

affected by fuel hydrocarbons may be encountered during construction dewatering. 

The most substantial UST release site near the proposed Fourth and Townsend Street subsurface 

station is SF Newspaper Agency (Site 31), which reportedly has gasoline product floating on the 

water table. Depending on the lateral extent of the floating product, dissolved-phase gasoline 

constituents, and groundwater flow direction, gasoline hydrocarbons from this site could affect 

construction dewatering and worker health and safety. 

Townsend Street. The subway portion of Townsend Street potentially intersects an additional 

three identified hazardous materials sites (Sites 30 and 34). Potential impacts associated with 

Sites 30 and 34 are similar to those discussed above for the storage yard and surface tracks, with 

the following exceptions: 

• Soil disposal costs may be increased due to the large quantity of soils that would be 

excavated during cut-and-cover construction; and 

• The subway excavation would require dewatering of groundwater potentially 

contaminated by fuel hydrocarbon constituents. 

Construction of the cut-and-cover subway would require disturbance of fill that potentially 

contains lead and PAHs in addition to fuel hydrocarbons, as is the case with other components of 

the surface track, storage yard, and Townsend Street alignments. 

The Tunnel Option would extend through bedrock and would be below the current groundwater 

table throughout the entire alignment. Because fuel hydrocarbons associated with UST sites 

have a tendency to float on the groundwater table, it is unlikely that hydrocarbon-affected 

bedrock would be encountered. Therefore, impacts from potential UST release sites would be 

limited to contaminated groundwater or floating product that could enter the tunnel excavation or 

require special disposal when intercepted by the tunnel dewatering system. Entry of dissolvedphase or free-phase fuel hydrocarbons into the tunnel could create explosion or inhalation 

hazards. If present in the dewatering system effluent, fuel hydrocarbons may prevent direct 

discharge of the effluent to the sanitary sewer without appropriate treatment. 

Identified UST release sites near the tunnel section (Sites 15, 17, 18, 20, and 27), are either 

unconfirmed releases or listed as requiring no further remedial action. Sites 12, 13, 14, 16, 19, 

and 21 do not have a current status listed in the agency reports. Floating product was reportedly 

present at an unspecified commercial building at 101 Townsend Street (Site 20), however the 

agency reports a current status of “remediation completed or deemed unnecessary.” 
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5.21 CONSTRUCTION IMPACTS 5-221 

Metals and PAHs have been detected at sites in the Townsend Street vicinity (Sites 12, 13, and 

25). These contaminants are encountered in fill material and, to a limited extent, may extend 

down into underlying native soils but are not expected to be present in bedrock. In addition, low 

concentrations of metals and PAHs may be present in groundwater intercepted by the tunnel 

dewatering system. Contamination in soil would not likely affect this section of the tunnel. 

Soils overlying bedrock may contain metals, PAHs, and/or fuel hydrocarbons at sufficient 

concentrations to require worker health and safety precautions and special handling and disposal 

of excavated soil. 

Folsom to Transbay Terminal Segment 

Three of the identified hazardous materials sites are located near the cut-and-cover subway 

segment north of Folsom Street to the proposed underground terminal. The first site, Pacific Bell 

(Site 14), is shown as the site of a release of diesel into surrounding soil. It is also listed as a 

small quantity generator of hazardous wastes. The second site is located at 171 New 

Montgomery Street (Site 11) and is listed with a status of “remediation completed or deemed 

unnecessary.” Dahl Beck Electric Company (Site 10) is reported as having a gasoline release to 

soil with a status of “remediation completed or deemed unnecessary.” 

This cut-and-cover section is located outside of known areas of coal tar residues, but may still 

have been affected by low concentrations of PAHs. Similarly, this subway section is not 

included within the Article 22A50 zone but may encounter fill soils that contain elevated 

concentrations of lead or other metals. 

Transbay Terminal. UST release sites located near this cut-and cover section include sites 1, 2, 

4, 6, 7, and 8. All of these sites are listed as either unconfirmed, “case closed,” or “remediation 

completed or deemed unnecessary." There are known coal tar deposits in this area from the 

former San Francisco Gas Light Co. (Sites 3 and 5). The identified UST release sites include the 

Federal Reserve Bank (Site 1), Talco Inc. (Site 2), the Caltrans-Transbay Terminal site (Site 4), 

the former U.S. Marine Corps Supply Depot (Site 6), 524 Howard Street HOA (Site 7), and the 

Transportation Department (Site 8). Details regarding the nature of contamination at these sites 

are discussed below, with contamination from UST releases for all three sites discussed first, 

followed by specifics related to the presence of asbestos at the Transbay Terminal itself.

Construction of the new Caltrain underground terminal would require excavating potentially 

contaminated soils and dewatering of groundwater that may include hazardous contaminants. A 

portion of the underground terminal is located within the Article 22A zone, indicating that soils 

encountered during construction are likely to have elevated concentrations of lead and other 

metals and possibly PAHs. In addition, coal tar deposits are likely to be encountered in the 

eastern half of the terminal excavation while surrounding soils are expected to contain PAHs 

associated with coal tar residues. The underground terminal would be located adjacent to a 

former coal gas plant, the San Francisco Gas Light Company (Sites 3 and 5). Elevated levels of 

 

50 Article 22A of the San Francisco Public Health Code (Maher Ordinance). 
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5-222 5.21 CONSTRUCTION IMPACTS

PAHs in soil have been detected at several nearby sites, including the Oriental Warehouse 

(Site 12) and an unspecified site at Second and Townsend Streets (Site 13), as well as several 

other sites along Howard Street between Fremont and Main Streets. In addition to soil 

contamination, groundwater contamination associated with the coal tar residues has also been 

detected in these areas and may potentially affect dewatering operations. 

In addition, there is one UST site near the proposed underground terminal that has the potential 

to affect construction of the station. The Federal Reserve Bank (Site 1) is located approximately 

400 feet from the proposed underground terminal and is reported to have had an unconfirmed 

release of gasoline that affected groundwater. 

Based on the presence of UST releases at and near the proposed terminal, and on the probability 

that other unreported UST releases have occurred in the area, it is likely that some soils 

encountered during construction would have detectable concentrations of fuel hydrocarbons. 

Depending on the lateral extent of dissolved-phase constituents and groundwater flow direction 

during dewatering, gasoline hydrocarbons from past UST releases and groundwater 

contamination associated with coal tar residues could affect construction dewatering and worker 

health and safety. If present in the dewatering system effluent, fuel hydrocarbons may prevent 

direct discharge of the effluent to the sanitary sewer without appropriate treatment. 

Asbestos-Containing Building Materials at the Transbay Terminal Building. Caltrans 

performed an asbestos survey of the Transbay Terminal in 1986 that identified asbestoscontaining building materials (ACM) including domestic water and heating pipe insulation, 

mechanical equipment insulation, and floor tiles. As part of its 1993 renovation of the terminal 

building, Caltrans removed asbestos-containing thermal systems insulation, vinyl floor tile and 

mastic, and transite ducting from various areas of the terminal. Also in 1993, the reinforced 

concrete roof of the terminal was replaced with a lightweight metal roof. This replacement 

included the removal of approximately 100,000 square feet of built-up asphalt and gravel 

roofing, vent pipes, and cold joint fillers, all of which were reported to contain asbestos. 

Based on this information, some or all of the identified ACM has been removed from the 

Transbay Terminal. The presence of additional ACM cannot be ruled out without additional 

survey. Demolition of the terminal without prior abatement of ACM could result in exposure of 

construction workers and the general public to asbestos fibers. 

Mitigation Measures. Handling and storage of fuels and other flammable materials during 

construction would follow California OSHA and local standards for fire protection and 

prevention. These measures include appropriate storage of flammable liquids and prohibition of 

open flames within 50 feet of flammable storage areas. 

Prior to construction, the potential presence of contaminants in soil and groundwater would be 

investigated using conventional drilling, sampling, and chemical testing methods. Based on the 

chemical test results, a mitigation plan would be developed to establish guidelines for the 

disposal of contaminated soil and discharge of contaminated dewatering effluent, and to generate 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5.21 CONSTRUCTION IMPACTS 5-223 

data to address potential human health and safety issues that may arise as a result of contact with 

contaminated soil or groundwater during construction. The investigation and mitigation plan 

would follow the requirements of Article 22A in the appropriate areas along the alignment. 

With construction projects of this nature and magnitude, there are typically two different 

management strategies that can be employed to address contaminated soil handling and disposal 

issues. Contaminated soil can be excavated and stockpiled at a centralized location and 

subsequently sampled and analyzed for disposal profiling purposes in accordance with the 

requirements of the candidate disposal landfill. Alternatively, soil profiling for disposal purposes 

can be done in-situ so when soil is excavated it is loaded directly on to trucks and hauled to the 

appropriate landfill facility for disposal based on the in-situ profiling results. A project of this 

nature could also combine both strategies. 

Soils removed during excavation and grading activities that remain at a centralized location for 

an extended period of time would be covered with plastic sheeting to prevent the generation of 

fugitive dust emissions that migrate offsite. Additionally, dust control measures would be 

implemented during construction grading and excavation as necessary to minimize offsite 

migration of contaminants. Soil for disposal at a landfill or recycling facility would be 

transported by a licensed waste hauler, under appropriate manifests or bill of lading procedures, 

as required. 

Chemical test results for groundwater samples along the alignment would be used to obtain a 

Batch Discharge Permit under Article 4.1 of the San Francisco Department of Public Works as 

well as to evaluate requirements for pretreatment prior to discharge to the sanitary sewer. 

Effluent produced during the dewatering of excavations would be collected in onsite storage 

tanks and periodically tested, as required under discharge permit requirements, for potential 

contamination to confirm the need for any treatment prior to discharge. If required, treatment 

may include: 

• Settling to allow particulate matter (total suspended solids) to settle out of the effluent in 

order to reduce the sediment load as well as reduce elevated metal and other contaminant 

concentrations that may be associated with suspended sediments; and/or 

• Construction of a small-scale batch waste water treatment system to remove dissolved 

contaminants (mainly organic constituents such as petroleum hydrocarbons (gas, diesel, and 

oils), BTEX, and VOCs) from the dewatering effluent prior to discharge to the sanitary 

sewer. A treatment system would also likely employ the use of filtration to remove 

suspended solids. 

A detailed mitigation plan for the handling of potentially contaminated soil and groundwater will 

be developed prior to starting project construction. 

Dewatering systems would be designed to minimize downward migration of contaminants that 

can result from lowering the water table if necessary based on environmental conditions. As 

necessary, shallow soils with detected contamination would be dewatered first using wells 
CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5-224 5.21 CONSTRUCTION IMPACTS

screened only in those soils. Dewatering of deeper soils would then be performed using wells 

screened only in the zone to be dewatered. Dewatering wells would be installed using drilling 

methods that prohibit shallow contaminated soils from being carried deeper into the boreholes. 

Workers performing activities on site that may involve contact with contaminated soil or 

groundwater would be required to have appropriate health and safety training in accordance with 

29 CFR 1910.120. A Worker Health and Safety Plan (HSP) would be developed for the project 

and monitored for the implementation of the plan on a day-to-day basis by a Certified Industrial 

Hygienist (CIH). The HSP would include provisions for: 

• Conducting preliminary site investigations and analysis of potential job hazards; 

• Personnel protective equipment; 

• Safe work practices; 

• Site control; 

• Exposure monitoring; 

• Decontamination procedures; and 

• Emergency response actions. 

The HSP would specify mitigation of potential worker and public exposure to airborne 

contaminant migration by incorporating dust suppression techniques in construction procedures. 

The plan would also specify mitigation of worker and environmental exposure to contaminant 

migration via surface water runoff pathways by implementation of comprehensive measures to 

control drainage from excavations and saturated materials excavated during construction. 

Mitigation measures for ACM would include identification of all available asbestos survey and 

abatement reports and supplemental asbestos surveys, as warranted. Identified ACM would 

require abatement prior to building demolition. Removal and disposal of ACM would be 

performed in accordance with applicable local, state, and federal regulations. In addition to 

ACM, lead-based paint may also require abatement prior to building demolition. A lead-based 

paint survey would be required to determine areas where lead-based paint is present and the 

possible need for abatement prior to demolition. 

5.21.16 AESTHETICS & VISUAL IMPACTS

As described in Section 5.20, project construction for all three components would be multiphased and would occur in different locations at different times. Wherever and whenever 

construction occurs, construction equipment and supplies would be visible, and evidence of 

construction activity would be noticeable to area residents, employees, and visitors. Short-term 

visual changes as a result of construction activities are a common and accepted feature of the 

urban environment, and generally mitigation is not required. Nonetheless, the TJPA and JPB 

would require the project contractors to ensure that construction crews working at night direct 

any artificial lighting onto the work site in order to minimize "spill over" light or glare effects on 
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5.21 CONSTRUCTION IMPACTS 5-225 

adjacent areas. The TJPA and JPB, through its on-site field office, would make all efforts 

possible to minimize specific aesthetic and visual effects of construction identified by 

neighborhood businesses and residents. 

5.21.17 GEOLOGIC IMPACTS ON PROJECT CONSTRUCTION

The primary geologic units that could adversely affect construction activities of the 

Terminal/Extension Project include artificial fill and bedrock. Impacts associated with these 

units are discussed in the following sections. 

Fill. Fill soils possess adverse characteristics such as rubble, heterogeneity of composition and 

depth, and locally high permeability. Because of localized areas of high permeability, fill soils 

may be difficult to dewater during construction of tunnels and building foundations. Dewatering 

requirements affect the cost of constructing tunnels and the underground station by increasing 

the cost to (1) install and operate dewatering systems for the tunnel and station excavations, and 

(2) discharge the dewatering effluent if the water contains contaminants such as metals or 

petroleum hydrocarbons. The impacts associated with handling and disposal of contaminated 

dewatering effluent are further discussed in Section 5.21.14. 

Bedrock. Impacts to the Terminal/Extension Project from poor quality bedrock would be 

limited to the cut-and-cover section under Second Street from Brannan Street to Folsom Street. 

Cut-and-cover construction in this area will make use of special shoring techniques discussed in 

Section 5.20. 

5.21.18 SAFETY AND SECURITY

Evaluation of long-term project impacts on public safety and security is presented in 

Section 5.17. This section focuses only on the short-term safety and security impacts of 

construction activities. 

Best construction management practices would be required to be in place to ensure the safety of 

construction workers, local residents, and employees during project construction. Fencing and 

lighting of construction and staging areas, and recognized safety practice requirements for the 

use of heavy equipment and the movement of construction materials would be implemented to 

avoid accidents. During construction, the Construction Manager would be responsible for job 

site safety and security. Emergency response personnel within San Francisco would be 

available for immediate response on an as-needed basis. 
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5-226 5.22 IRREVERSIBLE AND IRRETRIEVABLE 

COMMITMENT OF RESOURCES

5.22 IRREVERSIBLE AND IRRETRIEVABLE COMMITMENT OF RESOURCES 

The No-Project Alternative would not directly involve the use of resources, except insofar as it 

assumes implementation of planned and programmed capital improvements, which require 

money, materials, and labor to construct. This would include electrification of the entire Caltrain 

line from Gilroy to the Fourth and Townsend Streets Station in San Francisco and the need to 

upgrade or retrofit the existing Transbay Terminal to meet current seismic safety requirements. 

The Transbay Terminal / Caltrain Downtown Extension / Redevelopment project would involve 

major capital improvements, which would require money, materials, and labor, as shown in 

Tables 2.2-1, 2.2-2 and 2.2-3. Total project costs for the Locally Preferred Alternative are 

estimated to be $2.083 billion year-of-expenditure costs, including all project components. 

Because the Transbay Terminal and Caltrain Downtown Extension Alternatives would reduce 

vehicle miles of travel within the region when compared to the No-Project Alternative, it would 

also reduce the level of vehicular fossil fuel consumption. Further reductions could occur 

because local transit operators (Muni and SamTrans) would no longer have to serve the Fourth 

and Townsend Streets terminal. 

Operation of trains on the 1.3-mile extension would require the use of electricity for power, and 

would have greater propulsion energy requirements than the No-Project Alternative, although the 

energy requirements per passenger trip would be similar or less. 

Operation of the new terminal would require the use of energy for lighting, heating, cooling, but 

the terminal would be designed to incorporate the latest sustainable features that would allow the 

building to use site-specific wind, daylight, and shading to reduce the building’s energy needs. 

The design of the roof and exterior walls would facilitate natural ventilation and natural lighting 

of the interior. Use of mechanical cooling would be limited to enclosed office areas and data 

equipment rooms. Photovoltaic panels are proposed on the roof structure to capture solar energy. 

Rainwater would be collected and used for maintenance and irrigation of landscaping. 

The new development proposed in the surrounding vicinity would also use energy for lighting, 

heating, and cooling, but this use would be somewhat offset by a reduction in the use of 

vehicular fuel, since these new residential, commercial, and retail spaces would be very close to 

a regional multi-modal transit hub. Automobile use should be less than it would be were the 

same level of development to be constructed in other, non-transit-oriented locations. 
 CHAPTER 5: ENVIRONMENTAL CONSEQUENCES AND MITIGATION MEASURES 

5.23 RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF THE ENVIRONMENT AND THE 

MAINTENANCE AND 

ENHANCEMENT OF LONG-TERM PRODUCTIVITY 5-227 

5.23 RELATIONSHIP BETWEEN LOCAL SHORT-TERM USES OF THE

ENVIRONMENT AND THE MAINTENANCE AND

ENHANCEMENT OF LONG-TERM PRODUCTIVITY 

The Transbay Terminal / Caltrain Downtown Extension / Redevelopment Alternatives would 

involve short-term uses of the environment during the construction period through the use of fuel 

and construction materials, through increases in noise levels and air pollutants, and through 

increases in traffic congestion and detours around construction sites. These short-term effects 

and uses of resources would result in long-term benefits such as improved access to downtown 

San Francisco from the Peninsula, improved connectivity between and among Caltrain and other 

regional transit systems, and a more vital mix of transit-oriented land uses in the Transbay 

Terminal vicinity, including housing. These improvements, when combined with the decrease in 

vehicle miles of travel on the regional highway network, improved air quality, and greater 

efficiency in energy consumption, would contribute to the long-term livability, and therefore 

productivity, of the region. 

The current Transbay Terminal concept includes “a wide ranging sustainable approach to the 

terminal building that uses the natural wind flows in downtown San Francisco to ventilate and 

cool the facility, harnesses solar energy for passive hearing and cooling, and established 

sustainability protocols for materials, construction procedures, and long-term building 

operations.”51 Additional measures would be included in the design and specification of 

equipment to ensure energy efficiency, thereby helping to reduce the long-term energy 

requirements and the operating costs of the project. 

 

51 Transbay Terminal Improvement Plan, MTC, 2001, pg. 18.