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ATTACHMENT 4-B Consultants in Acoustics AudioNisual System Dasign and Telecommunications 130 Sutter Street, Suite 500 San Francisco California 94104 Tel: 415 397 0442 Fax: 415 397 0454 info®crosalter.com www.crosalter.com Charles M Salter, PE Davitl R Schwind, FAES Anthony P Nash, PE Eva Duesler Thomas A Schintller, PE Kenneth W Graven, PE Edc L Broadhurst, PE Philip N Santlers Robert P Alvarado John C Freylag, PE Durantl R Begault, Ph.D. Michael D Toy, PE TTOmas J Corbett Ross A Jerozal Jason R Duty Cristina L Miyar Joey G O'Angelo Eric A Vea Joshua M Roper Troy Gimbel Rantly D Waldeck Peter K Holst Antlrew L Stanley Christopher A Peltier Timothy G Brown JeR Clukey Ethan Salter Elaine V Hsieh Alexander K Salter Jeremy L Decker Ryan McClain Claudia Kraehe Heather Migut Josselyn Salter Candice Huey Brian Good Marva D Noortlzee Debbie Garcia Jasmine Recidoro Alison Whitson Charles M Salter Associ 24 Mazch 2008 Jerry Raney 332 Hartford Road Danville, CA 94526 Email: jerryraney@aol.com rtes;. inc Subject: 4693 Augustine Street -Environmental Noise Study CSA Project No. 08-0038 Dear Jerry: As requested, we have conducted an environmental noise study for this project, based on the drawings received by our office on 13 Mazch 2008. The project consists of the addition of three single-family homes (i.e., Lots 3, 4 and 6) to a parcel which already has three single-family homes (i.e., Lots 1, 2, and 5). The purpose of the environmental noise study is to quantify the existing and future noise environment at the project site, compare the noise environment with applicable standards, and propose mitigation measures as necessary. This letter summarizes the results of our study. ACOUSTICAL CRITERIA The City of Pleasanton's 1996 General Plan stipulates that where the exterior DNL1 exceeds 60 dBA, the interior DNL should be mitigated to no higher than 45 dBA. For residential units exposed to railroad noise, the City also stipulates a maximum noise level (Lm~)Z goal of 50 dBA in bedrocros and 55 dBA in other habitable rooms. The City has an exterior noise level goal of DNL 60 dBA at the backyards ofsingle-family homes. EXISTING AND FUTURE NOISE ENVIRONMENT To quantify the existing noise environment at the project site, we conducted one long-term 96-hour measurement between 15 and 20 February 2008 (Friday to Wednesday). The monitor was located approximately 17-feet west of the Augustine Street centerline and Day-Night Average Sound Level (DNL) - A descriptor established by the U.S. Environmental Protection Agency to describe the average day-night level with a penalty applied to noise occurring during the nighttime hours (10 pm to 7 am) to account for the increased sensitivity of people during sleeping hours. Z L,,,a,r -The maximum A-weighted sound level measured during a period of time.