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99 o Traffic noise along Main Street, Marshall Street, Walnut Street and Spring Street would not be expected to increase significantly. o Estimated traffic noise along Broadway adjacent to and just east of the site would be expected to increase by approximately 2 dB above the measured levels, which would be considered less than significant. In addition, the Salter noise study (pp. 2 and 6-8) concluded:  Windows and exterior doors will require sound rated construction to meet CALGreen indoor environmental noise standards. The initial Salter recommendation is use of a Sound Transmission Class (STC) insulation rating of up to STC 35 to reduce hourly average noise levels to the Leq(h) indoor criterion of 50 dB.  Though the Commons would be exposed to future traffic noise, the distance and natural shielding from roadways would prevent noise generated from estimated future traffic levels from exceeding the City of Redwood City “Normally Acceptable” standard for Community Noise Equivalent Levels (CNEL) established for open space/recreational land uses and “Conditionally Acceptable” for Commercial – Office Professional/Technology uses 17  For informational purposes (not a CEQA-defined impact): Exterior building balconies/terraces and the roof deck could be subject to noise levels between CNEL 64 dB to 70 dB; project component plans indicate use of glass railings around the perimeter of these spaces, which would provide some shielding for a seated person and could, depending construction, reduce noise levels by approximately 5 dB.  Estimated noise from project component-generated traffic and/or project component HVAC equipment would not be expected to significantly increase environmental noise at the nearest offsite residences. As discussed in the Salter noise study (Salter, p. 8), “Equipment will need to be selected and located to meet the City Code criteria, which limits noise levels to 55 dB(A) at any point along the property line. If needed, noise reduction measures are expected to consist of equipment selection, shielding with barriers and/or parapet walls, equipment enclosures, etc.” With completion of Mitigation Measure NO-2 (including City approval of the rooftop mechanical equipment and equipment screening design), and compliance with standard conditions of approval to implement the City’s Noise Ordinance and Noise Element, this project component will not expose persons to or generate excessive noise levels on a project or cumulative level (because other construction projects will also be subject to the noise control measures noted). The impact of this project component would be considered less than significant, and no additional mitigations would be required. Therefore, the 1900 Broadway project component would not create new impacts or increase impacts, and there is no new information of substantial importance for CEQA purposes. b. Regarding groundborne vibration and groundborne vibration noise levels, the DTPP program EIR (pp. 11-23 through 11-29) concluded that potentially significant temporary noise and vibration impacts could be generated by demolition and construction activities in the DTPP area. The DTPP program EIR (p. 11-22) also identified potentially significant intermittent vibration impacts for residential projects located within 100 feet of the centerline of the Caltrain railroad tracks. These impacts were reduced to less than significant with mitigation. The DTPP Plan-Wide Amendments program SEIR (pp. 11-27 through 11-28) generally concurred with the DTPP conclusion with respect to DTPP development construction period groundborne vibration effects. It found the same types of construction activities would occur and the distances to the nearest receptor location would be similar, thereby posing similar level of potential impact. The Plan-Wide Amendments included Mitigation Measure NO-3 (“Vibration Reduction”), which restates Mitigation Measure 11-3 from the DTPP Final EIR with minor text revisions (“clarifying amendments”). Mitigation Measure NO-3 requires implementation of ground-borne vibration abatement measures, such as restriction of vibration-generating activity, notification of nearby occupants, consultation with the City regarding pre-drilling holes for pile driving, conducting a pre-construction site survey of historic structures within 200 feet of pile driving activities for City review, and monitoring pile-driving activities. The Salter noise study (Salter p. 11) determined, “The project [component] is not expected to include any significant sources of groundborne vibration or groundborne noise.” As noted above, the proposed project component would involve demolition and construction activities. DTPP EIR Mitigation Measures 11-3 and 11-4 would reduce these impacts to less-than-significant levels through scheduling, 17 The City of Redwood City General Plan Public Safety Element Figure PS-15 (“Redwood City Noise Guidelines for Land Use Planning”) indicates that the “normally acceptable” standard for commercial - office professional/technology use is CNEL 65 dB or below and “conditionally acceptable” is CNEL 65 – 75 dB and the “normally acceptable” standard for open space/recreation is CNEL 75dB. ATTY/RESO.0074/CC RESO 847 WOODSIDE (CEQA) - EXHIBIT 1 - CEQA CONSISTENCY CHECKLIST REV: 10-23-24 VR Page 99 of 135