Years before any construction happened on VTA's BART Silicon Valley Phase I (Berryessa Extension), a rigorous environmental process took place to understand any impacts to the project corridor. Below is a record of all environmental documents for Phase I.
VTA's BART Phase I Environmental Documents
FTA and VTA prepared a Supplemental Environmental Impact Report to address environmental effects of VTA’s BART Silicon Valley Phase I (Berryessa Extension). The draft and final documents are available below.
Previous Environmental Documents
VTA's Project Approval
On March 3, 2011, the VTA Board of Directors approved VTA’s BART Silicon Valley Phase I (Berryessa Extension) through the following actions:
- Certified the 2nd Supplemental Environmental Impact Report met the requirements of the California Environmental Quality Act (CEQA); represents the independent judgment of the Lead Agency; and was presented to and reviewed and considered by the VTA Board of Directors prior to making its decision on the Phase I Project.
- Adopted the Findings, Facts in Support of the Findings, and Statement of Overriding Considerations
- Adopted the Mitigation Monitoring and Reporting Program (MMRP)
- Adopted the Recommended Project Description
BART's Project Approval
On April 14, 2011, the BART Board approved the Phase I Project with the following actions:
- Accepted the Project SEIR;
- Adopted VTA's Findings and Statement of Overriding Considerations for the SEIR
- Pursuant to the Comprehensive Agreement, approved the Project.
FTA's Project Approval
FTA issued the Record of Decision (ROD) for Phase I (Berryessa Extension) on June 24, 2010, which is the federal environmental approval for the National Environmental Protection Agency (NEPA) Process.
Mitigation Monitoring Reporting Program (MMRP)
VTA committed to a number of mitigations in the Phase I environmental documents. Through the Mitigation Monitoring Reporting Program (MMRP), VTA tracked its progress on those commitments. MMRP quarterly reports are available below.
Noise and Vibration
Noise and vibration are two issues for which VTA – and most transit agencies – receive many comments, concerns and questions. To reduce impacts on our surrounding communities, VTA employs a suite of mitigation measures through project design, planning, construction and operation.
During the federal and state environmental analyses for VTA’s BART Silicon Valley project, VTA identified areas and residences likely to be impacted by train noise or vibration during construction and operations. The information below showcases the mitigation measures that were implemented to ensure noise and vibration was reduced to be within state and federal criteria, how noise and vibration were tested, how noise and vibration were managed during construction and will continue during passenger service.
Noise Regulations for Federally Funded Transit Projects
What regulations exist for noise and vibration?
This project is required to comply with federal and state noise and vibration levels (thresholds) in accordance with the Transit Noise and Vibration Impact Assessment, Federal Transit Administration, May 2006 and the California Noise Insulation Standards, California Administrative Code, Title 25, Chapter 1, Subchapter 1; Adopted February 22, 1974.
The federal noise impact criteria assess the changes in noise and compare existing ambient conditions to noise with BART operations. These take into account different land uses with daytime and nighttime activities, including nighttime sensitivity where people sleep is of utmost importance. Noise level thresholds are established for an average noise level over a 24-hour period. Therefore, there will be periods of time where noise level is higher or lower than the threshold without exceeding the 24-hour average threshold.
More detailed information regarding noise and vibration studies can be obtained by reviewing the project’s published environmental documents above.
Noise and Vibration due to Future Train Service
How and what noise and vibration will be generated from future BART train service?
Transit noise and vibration are generated by BART trains in motion. The noise comes from the electric motors that propel the train and the rolling noise of the steel wheels on the tracks. Vibrations result from the weight of the train rolling over the tracks. In addition to the train, noise and vibration is generated by the project’s system equipment, passenger stations, buses, and parking facilities.
What are considered sensitive areas for noise and vibration?
Certain structures or land uses are considered sensitive to noise and vibration. Examples include residences or buildings where people normally sleep, hospitals, hotels, schools, libraries, churches, and certain parks and recreational facilities.
What has VTA done to improve the design and minimize potential noise of BART trains that are on elevated track?
North of Berryessa Road, the BART tracks are elevated and include a 4- to 6-foot high soundwall above the elevated tracks to reduce BART train noise to levels below the federal and state criteria. An 8-foot high community wall was constructed along residential areas to the east of the Berryessa BART Station campus between Berryessa Road and Mabury Road to reduce BART train and station traffic noise impacts on the surrounding residents.
Noise and Vibration Mitigation Strategies
How does VTA mitigate for noise and vibration impacts from future BART service?
VTA has employed a combination of measures in impacted locations along the corridor, including use of vibration-dampening track-way elements such as ‘tire derived aggregate’ (rubber pieces) and ‘floating slab’ (concrete slab supported by a resilient layer). To minimize noise, VTA has constructed soundwalls, built equipment enclosures, and applied acoustic absorptive coatings to trenches and soundwalls. These and other measures are highlighted below:
Tire Derived Aggregate (TDA) – Scrap vehicle tires are transformed into a vibration-absorbing TDA material. TDA was installed beneath the tracks in some locations, to reduce vibration to within federal criteria. This engineering method was successfully installed by VTA on the Vasona Corridor Light Rail extension in the City of Campbell and along the Berryessa Extension. TDA is installed as a one-foot thick layer of tire shreds beneath the track bed. This method also provides a good use for recycled tire material.
Floating Slab – The BART tracks are affixed to a concrete pad that sits on top of thick rubber bearing pads, which help absorb vibration generated by the train. VTA installed floating slab at locations where TDA would not provide sufficient vibration mitigation to meet the federal threshold.
Track Configuration and Maintenance – Activities such as rail grinding and track inspection reduce rail defects that lead to higher than normal noise and vibration levels. Regular rail grinding helps to minimize noise and vibration generated by trains traveling over defects or imperfections on the rail. The 10-mile Berryessa Extension project is a relatively straight alignment without any major turns. Significantly less noise is generated by trains running on straight tracks.
Regular Vehicle Maintenance – Activities such as periodic inspections and tests will help to identify problems and necessary corrective actions to minimize system noise and vibration levels. This includes wheel truing, which is the process of cutting away a thin layer of steel on a wheel’s outer diameter to smooth out rough or flat spots and ensure that the wheels are perfectly round.
Soundwalls – In addition to existing sound walls which provide noise insulation, approximately 12,500 linear feet of new soundwalls were constructed as part of the mitigation efforts for the project, including portions of elevated track near Berryessa Road. Typically, the location of a soundwall is 10 to 15 feet from the center of the BART tracks and the height varies based on location and need. In areas where a soundwall is recommended on both sides of the alignment, noise absorbing soundwalls are commonly required to prevent train noise echo. Most of the existing soundwalls remained, and where required, new soundwalls were constructed within the project corridor. In limited cases, existing soundwalls were replaced with new soundwalls to accommodate the construction or relocation of underground utilities.
Systems Equipment – Emergency power generators and other electrical equipment were enclosed in buildings to ensure that there will be no adverse noise effect associated with operations and periodic routine testing.
Residential Noise Insulation Program (RNIP)
What is the Residential Noise Insulation Program?
The Residential Noise Insulation Program, or RNIP, addressed the identified concern of excessive noise in the second story living spaces of some homes along the BART tracks. Of the 525 homes tested, 252 multi-story homes required additional mitigation to meet state and federal thresholds. These homes received second-story noise mitigation measures that included acoustical (multi-paned) windows, solid core doors, insulation and/or weather stripping.
Permission was sought from property owners to take interior and exterior sound measurements. Portable loudspeakers were positioned outside the house near the BART tracks and were used to determine the insulating properties of the existing windows and whether future projected noise levels would exceed acceptable interior noise levels as defined by state and federal standards.
Only homes that showed second story noise levels above state and federal standards qualified for the RNIP. These homes received acoustical windows, solid core doors, and/or insulation upgrades at no cost to the individual homeowner because the costs were included in the overall construction cost of the project.
Who Decided What Work was to be Done at Eligible Residences?
The need for acoustical treatments such as new and enhanced windows, doors and or insulation, was determined by a specialized acoustical engineering consultant team. This team evaluated the needs of each residence and identified treatments necessary to reduce noise to at or below state and federal thresholds. Proposed treatments were reviewed with VTA staff and then approved by each homeowner before installation.
How Can I Contact VTA if I Have Questions or Concerns?
VTA’s BART Silicon Valley Community Outreach Team provides project information and responds to project inquiries or concerns via the project hotline or email.
VTA’s BART Silicon Valley website links to project fact sheets, news releases, maps, graphics, videos, and other multimedia resources and is regularly updated.
Program updates and information are also available via Facebook facebook.com/bartsv and Twitter twitter.com/bartsv. In addition to information provided, residents, businesses, commuters, and the public will receive project updates via news stories, newsletters, signage, email updates, and fliers during construction.
If you are interested in receiving email updates, please sign up to allow VTA to communicate with you via email.
VTA BSV Hotline: (408) 321-2345