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portions of parks, will fail between 60-65 dB Ldn. Residentiai areas greater <br />than 65 dB require subsequent anaiysis and mitigation, except for golf <br />course-oriented lots. <br /> <br />Alternatives: <br /> <br />Raise berms or build berms/walls to achieve 65dB Ldn at golf course and <br />parks, and 60 dB Ldn at private yards. <br />Modify land use locations to remove single-family houses from areas <br />where berms/walls cannot be constructed (by Union Pacific Railroad <br />freeway overpass) and to replace them with multi-family, golf course, or <br />other uses which can locate in a satisfactory noise environment per <br />General Plan goals. <br />Require some (or ail) of individuai private yard areas to meet 60 dB <br />standards through lot-specific mitigation (walls at property lines, etc.) <br />Seek CalTrans permission to add soundwall at 1-680 pavement edge at <br />UPRR bridge area. <br /> <br />Discussion: <br /> <br />The site plan/noise mitigation can be modified to achieve quieter noise <br />environments, but they would be ,achieved at the expense of other goals. <br />The General Plan specifically allows tradeoffs in instances such as this, <br />and projects near freeways have been built to achieve interior noise level <br />standards while exterior levels typically exceed 60 dB Ldn. Tradeoffs for <br />this project have been fully explained in earlier reports. Staff believes the <br />mix of berms, walls, setbacks, sensitive land use locations, and <br />construction techniques achieve satisfactory results while also achieving <br />other City goals. CalTrans does not wish to add soundwalls along this <br />designated scenic route, and its maximum height walls for this freeway, <br />based on its scenic designation, would not provide sufficient noise <br />reduction to meet City goals. Staff investigated the possible use of "clear" <br />sound attenuating panels for the project. While such panels are being used <br />in some locales, CaiTrans has not sanctioned their use, and long-term <br />maintenance issues led staff to seek the present package of mitigations. <br />Clear panels remain an option at private lot line locations where views <br />from lot to golf course are desired, as maintenance obligations are easily <br />resolved in this instance. <br /> <br />Principles of Agreement: Not specificaily addressed; however, the land plan/major <br /> mitigations were a part of the "project" the Principles of Agreement were <br /> describing. <br /> <br />Staff Recommendation: Staff supports the package of mitigations incorporated in the <br /> initial approvals. <br /> <br />Substantive Issues/Alternatives Page 24 June 9, 1999 <br /> <br /> <br />