| Description of Project Alternatives How Many Different Alternatives Have Been Studied? At the outset of the DEIR/SDEIS effort, BART and SamTrans invited the public to participate in a "Public Scoping Meeting." The purpose of the meeting was to solicit ideas about how transit service could be improved in northern San Mateo County and to obtain public concerns about potential environmental impacts of the project alternatives. This meeting, held in July 1993, resulted in a menu of 19 alternatives, in addition to the Locally Preferred Alternative previously selected by the BART and SamTrans Boards of Directors and MTC. A detailed presentation of these alternatives, which include alignments that had been previously identified, and the reasons for rejection of certain alternatives are contained in the DEIR/Technical Appendix. How Were the Alternatives in the DEIR/SDEIS Selected? BART and SamTrans developed two sets of criteria to assist the Boards of Directors in identifying a smaller set of viable alternatives for evaluation in the DEIR/SDEIS. These criteria were selected by BART and SamTrans to highlight key operational, funding, engineering, and environmental differences among the alternatives. Engineering, logistic, feasibility requirements, and project goals were the basis for the first set of criteria. A project alternative had to satisfy these criteria if it were to be considered further. The second set of criteria were used to compare those alternatives that satisfied the first set of criteria, and included costs, funding availability, patronage, convenience for transit riders, potential wetland and endangered species impacts, land acquisition requirements, potential impacts to residences and businesses sensitive to noise and vibration, and potential construction impacts. These criteria are reproduced in Table S-2. Each alternative was evaluated in a comparative fashion, using these criteria. This screening process, along with meetings with each of the local jurisdictions along the project corridor, was used to select those alternatives recommended for further evaluation in the DEIR/SDEIS. What Alternatives are Studied in the DEIR/SDEIS? Seven basic alternatives and three major design options are analyzed in the DEIR/SDEIS:
Screening Criteria Used to Select BART-San Francisco Airport Extension Alternatives for the DEIR/SDEIS
The No Build Alternative is essentially a "do-nothing" scenario. The only new transportation improvements anticipated in the project vicinity include the extension of BART to Colma and the repair of I-280 between Highway 101 and 6th Street in San Francisco. This alternative provides a future baseline against which to assess project impacts. The TSM Alternative includes a number of transportation improvements that are planned by the Peninsula Commute Service (known as CalTrain, a diesel-operated commuter rail service along the Peninsula), San Mateo County, and local agencies. Key improvements in the project vicinity, in addition to those assumed under the No Build Alternative, include:
Table S-3 highlights some of the key differences between the BART "build" alternatives. Chapter 2 of the DEIR/SDEIS describes each alternative, including the No Build and TSM Alternatives, in detail. The BART "build" alternatives and design options are generally shown in Figures S-2 and S-3 and are summarized below. The proposed project or Locally Preferred Alternative proposes a BART extension, with a station at Hickey Boulevard in South San Francisco adjacent to the Tanforan Shopping Center in San Bruno, and a combined BART/CalTrain/Airport Light Rail Station (Intermodal Station) located west of Highway 101 near the SFIA terminals. From the Colma BART Station, presently under construction, the alignment would follow the SPTCo railroad right-of-way in subway through a below-grade Hickey Station to South Spruce Avenue, then ascend to grade at the Tanforan Station. . From the Tanforan Station, the alignment would descend into a subway configuration, paralleling the north side of I-380, pass under I-380, continue in subway along the easterly limit of the City of San Bruno, then ascend to ground level at the Airport Intermodal Station. This alignment would bypass downtown San Bruno. The ALRS would carry air passengers and SFIA employees from the Intermodal Station to the SFIA. An approximately 3,000-foot tailtrack would extend south from the Airport Intermodal Station. The I-380 Least-Cost Design Option of the proposed project calls for an alignment that would rise from the Tanforan Station on an aerial structure to I-380 over local streets and the CalTrain tracks, then descend and pass under I-380 in subway. The alignment would continue in a retained cut configuration along the easterly limit of the City of San Bruno, then ascend to ground level at the Airport Intermodal Station. Alternative III, the Base Case Alternative, follows the same route as the proposed project from Colma to the Tanforan Station. From the Tanforan Station to the Airport Intermodal Station, the alignment would continue along the SPTCo railroad right-of-way. It would be built with open, retained cut tracks from Colma to Mission Road; at grade and open, retained cut to the proposed extension of Hickey Boulevard; retained cut from the Hickey Station to south of South Spruce Avenue; at grade to the Tanforan Station; and aerial over streets in San Bruno, descending to the at-grade Airport Intermodal Station. The ALRS would carry air passengers and SFIA employees from the Intermodal Station to the SFIA. An approximately 3,000-foot tailtrack would extend south. ( Table S-3, Figure S-2) Alternative IV follows the same route as the proposed project north of Tanforan Avenue. The San Bruno station would be located at either Tanforan or just south of I-380 in San Bruno. South of Tanforan Avenue, the alignment would rise on an embankment to an aerial structure and curve eastward along San Bruno Avenue. The BART aerial alignment would continue east and cross over Highway 101, then curve south to a BART Airport Station located at the Airport long-term parking lot. South of the Airport Station, BART would parallel the SFIA's viaduct and descend under Highway 101, rising to an at-grade Millbrae Intermodal Station at Center Street. The ALRS would carry SFIA passengers and employees from the BART Airport Station and the Millbrae Intermodal Station to the SFIA. An approximately 3,000-foot tailtrack would extend at grade south of the Millbrae Intermodal Station. Alternative V follows the same route as the proposed project north of Tanforan Avenue. The San Bruno station would be located at Tanforan, 1-380/San Bruno, or in downtown San Bruno. BART would be in subway through downtown San Bruno from approximately San Bruno Avenue to Angus Avenue. South of Angus Avenue, BART would ascend to grade to a Millbrae Intermodal Station at Center Street. The ALRS would carry air passengers and SFIA employees from the Millbrae Intermodal Station to the SFIA. An approximately 3,000-foot tailtrack would extend at grade south of the Millbrae Intermodal Station. Design Option V-A is identical to the proposed project to Tanforan Avenue. A San Bruno BART/CalTrain/Airport Light Rail Intermodal Station would be located at either the proposed 1-380/San Bruno or Downtown San Bruno Station locations. South of the San Bruno Station, BART would be either in a subway or an aerial configuration to the proposed Airport Ground Transportation Center (GTC). The BART subway configuration would turn east under Highway 101 and then south into the subterranean level of the GTC. The BART aerial configuration also turns east and ascends from a subway to an aerial structure crossing over Highway 101 and then turns south to an aerial GTC Station immediately west of and perpendicular to the Airport GTC. Access to the SFIA terminals and employment centers would be available by elevator/escalator and the ALRS, As in Alternative V, BART would be in subway through downtown San Bruno, and an approximately 3,000-foot tailtrack would extend at grade south of the San Bruno Station. Design Option V-B is identical to the proposed project north of Tanforan Avenue. Under this design option, there would be no Tanforan Station but rather a San Bruno Intermodal Station located at either 1-380/San Bruno or downtown San Bruno. As in Alternative V, BART would be in subway through downtown San Bruno. An approximately 3,000-foot tailtrack would extend south of the San Bruno Intermodal Station. Design Option V-B would allow for either a future subway into the basement of the Airport GTC, as described in Design Option V-A, or a continuation south in the SPTCo right-of-way to Millbrae. Under Alternative VI, the alignment would follow the SPTCo right-of-way in subway from the Colma BART Station, presently under construction, to South Spruce Avenue. South of South Spruce Avenue, the alignment would be in subway through downtown San Bruno between San Bruno Avenue and Angus Avenue. The BART alignment would turn east under Highway 101 in subway, then turn south to a subway Airport International Terminal Station. BART passengers would access the proposed International Terminal by elevators and escalators, and other terminals by walking or transferring to the proposed ALRS. SFIA employees would access the station via the ALRS. South of the Airport International Terminal Station, BART would curve southwest under Highway 101 and rise to an at-grade Millbrae Avenue BART/CalTrain Station. An at-grade BART turnback and tailtrack would extend south of Millbrae Avenue approximately 3,000 feet. |
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
