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Environmental Checklist and City of Pleasanton–10x Genomics Project <br />Environmental Evaluation Initial Study/Mitigated Negative Declaration <br /> <br /> <br />112 FirstCarbon Solutions <br />Https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480024/ISMND/wp/21480024 10x Genomics Project Full Screencheck ISMND.docx <br />Operational/Mobile Source Noise Impacts <br />Less than significant impact. A significant impact would occur if implementation of the proposed <br />project would result in a substantial increase in traffic noise levels compared with traffic noise levels <br />existing without the project. Similar to the stationary source noise impact analysis above, for <br />purposes of this analysis, an increase of 4 dBA or greater above noise levels that would exist without <br />the proposed project would be considered a substantial permanent increase in traffic noise levels. <br />The FHWA highway traffic noise prediction model (FHWA RD-77-108) was used to evaluate existing, near- <br />term and far-term traffic noise conditions in the vicinity of the project site. The daily traffic volumes were <br />obtained from the traffic analysis prepared for the project by Fehr & Peers.90 The resultant noise levels <br />were weighed and summed over a 24-hour period in order to determine the CNEL values. The traffic <br />noise modeling input and output files are included in Appendix H of this document. Table 20, Table 21, <br />and Table 22 show a summary of the traffic noise levels for existing, near-term, and far-term traffic <br />conditions, respectively, as measured at 50 feet from the centerline of the outermost travel lane. <br />Table 20: Existing Traffic Noise Model Results Summary <br />Roadway Segment <br />CNEL (dBA) 50 feet from Centerline of <br />Outermost Lane <br />Existing (dBA) <br />CNEL <br />Existing Plus <br />Project (dBA) <br />CNEL <br />Increase over <br />Existing (dBA) <br />CNEL <br />Stoneridge Mall Road–north of Stoneridge Drive 64.8 64.8 0.0 <br />Stoneridge Drive–west of Springdale Avenue 67.1 67.4 0.3 <br />Stoneridge Drive–Springdale Avenue to Stoneridge Mall Road 68.8 69.2 0.4 <br />Stoneridge Drive–east of Stoneridge Mall Road 71.5 71.7 0.2 <br />Notes: <br />dBA = A-weighted decibel <br />CNEL = Community Noise Equivalent Level <br />1 Modeling results do not take into account mitigating features such as topography, vegetative screening, fencing, <br />building design, or structure screening. Rather it assumes a worst case of having a direct line of site on flat terrain. <br />Source: FCS 2021. <br /> <br />Table 21: Near-term Traffic Noise Model Results Summary <br />Roadway Segment <br />CNEL (dBA) 50 feet from Centerline of <br />Outermost Lane <br />Near-term <br />(dBA) CNEL <br />Near-term Plus <br />Project (dBA) <br />CNEL <br />Increase over <br />Near-term <br />(dBA) CNEL <br />Stoneridge Mall Road–north of Stoneridge Drive 64.9 65.0 0.1 <br />Stoneridge Drive–west of Springdale Avenue 67.9 68.1 0.2 <br /> <br />90 Fehr & Peers. 2021. 10x Genomics Traffic Impact Analysis. February 5.