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3 4 Noise r 6 TABLE 3.4-3 SUMMARY OF AMBIENT NOISE LEVEL MEASUREMENT RESULTS—9 P.M.TO 5 A.M. F t Measurement Site Average Measured Noise Level,dB(Rangel (Distance to C.L.)' L,q LAK A 43(35-48) 57(38-70) 44(36-50) 61 (46-72) 1 mm(40 feet) 65(57-68) 86(81-95) --..... ---................ _. ' 2(350 feet) 53(48-58) 69(60-85) 3(50 feet) 62(54-67) 82(7,5-98) 4(60 feet) 59(51-63) 79(73-86) 5(50 feet) 61 (53-66) 81 (74-94) ,.� 1 Distance from centerline of East River Road to noise level measurement site. 2 Noise level averages for the hours of 9 p.m.to 5 a.m.,September 27,2010 thru October 2,2010. Y L SOURCE: Bollard Acoustical Consultants,Inc.,August 18,2010(Appendix B). ' Probability of Awakening Due to Existing-Traffic Noise For this project,the American National Standards Institute, Inc.(ANSI)/Acoustical Society of n America(ASA)standard 12.9-2008 Part 6(ANSI/ASA S12.9-2008 Part 6)was used to estimate U the probability of awakenings of existing residents.in the project area due to existing project-area �--ss traffic. A total traffic volume of 250 vehicles was assumed to utilize East River Road in the project area during a typical 7-hour sleeping period(assumed to be 10 p.m. to 5 a.m.).A given vehicle passby was assumed to produce an average event noise exposure level of 50 d13 SEL within a residence 60 feet from the centerline of the roadway(75 d13 exterior SEL). The probability of the residents located 60 feet from East River Road awakening at least once from the existing traffic noise source was calculated to be approximately 92 percent.This result emphasizes the significant existing traffic noise exposure of residents near East River Road in the project area. 3.4.3 Impact and Mitigation Measures I Significance Criteria Consistent with the CEQA Guidelines Appendix G,the proposed project would result in a significant impact on the environment if it would result in: • Exposure of persons to or generation of noise levels in excess of standards established in any applicable plan or noise ordinance, or applicable standards of other agencies. • Exposure of persons to or generation of excessive ground-borne vibration or ground- borne noise levels • A substantial permanent increase in ambient noise levels in the project vicinity above levels existing without the project. F Munn 8 Perkins Quarry Excavation Permit 3.4-11 ESA 1211086 Draft EI R April 2011