14 ATTACHMENT 6 - Appendix A - E

City of Pleasanton–Spotorno Ranch Reduced Development Project Environmental Checklist Initial Study/Consistency Checklist 134 FirstCarbon Solutions https://adecinnovations.sharepoint.com/sites/PublicationsSite/Shared Documents/Publications/Client (PN-JN)/2148/21480021/Consistency Checklist/21480021 Spotorno Ranch Consistency Checklist ScreenCheck.docx more severe impacts related to short-term construction noise beyond what was previously analyzed in the 1998 HVSP FEIR. Stationary Operational Noise Impacts Project-related stationary operational noise impacts to off-site receptors would occur if the project would result in a substantial permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance. The City has established an operational noise level threshold of 60 dBA as measured at any point outside of the property plane. Project-related stationary noise sources would include new mechanical ventilation equipment. Typical new residential mechanical ventilation systems (such as exterior air conditioning units) generate noise levels up to approximately 60 dBA Leq at a distance of 25 feet. The closest off-site residential receptor is located directly adjacent to the project site’s northwestern corner and approximately 70 feet from where the potentially closest new mechanical equipment could be located. At this distance, these noise levels would attenuate to below 51 dBA Leq at the nearest noise sensitive receptor. As was found by the 1998 HVSP FEIR, these on-site stationary operational noise levels would not exceed the City’s noise performance threshold of 60 dBA. Therefore, the proposed project would not result in any peculiar effects and would not result in new or more severe impacts related to stationary noise sources beyond what was previously analyzed in the 1998 HVSP FEIR. Therefore, on-site stationary source noise impacts would be less than significant. Traffic Noise Impacts The 1998 HVSP FEIR found that project-related traffic would not have a significant impact on residential areas. The following discussion demonstrates that the proposed project (consisting of 22 units with 22 ADUs) would produce marginally more traffic than the 2018 project previously proposed on the site and would still have a less than significant impact on noise levels related to traffic. Project-related traffic noise impacts to off-site receptors would occur if the project would result in a substantial permanent increase in ambient noise levels in the vicinity of the project in excess of standards established in the local general plan or noise ordinance. The City has not established a threshold for a substantial noise increase for a project’s traffic noise increases. However, a change of 3 dB is the lowest change that can be perceptible to the human ear in outdoor environments. Therefore, for purposes of the project-related traffic noise impact analysis, an increase of greater than 3 dBA in ambient noise levels is considered a substantial increase. The Federal Highway Administration (FHWA) highway traffic noise prediction model (FHWA RD-77- 108) was used to evaluate existing and future project-related traffic noise conditions along modeled roadway segments in the vicinity of the project site. The projected future traffic noise levels on roadways adjacent to the site were analyzed to determine compliance with the City’s noise and land use compatibility standards. Traffic modeling was performed using data obtained from a traffic impact study conducted by Fehr & Peers (March 2018). The 2018 traffic impact study analyzed impacts associated with development of a greater number of residential units than is now being