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0 Munn S Perkins Quarry Excavation Permit 0 • Empty Trucks: Travel speed at 38-43 mph with engines in 8t1'gear at 700-800 rpm. • Loaded Trucks: Travel speed of 33-35 mph with engines in 6d'or 7d'gear at 1,400-1,600 rpm. Average resulting noise exposure from truck passbys using these "optimized"parameters was approximately 4 dB less than average noise exposure from passing trucks using unknown operating parameters.Therefore,it is expected that haul truck noise exposure may be reduced by approximately 4 dB given that all project trucks utilize the operating parameters described above.Resulting noise exposure at the closest residences to the project on East River Road(60 feet from centerline)would be approximately 62 dB Ldr,. This noise exposure is below the County's noise exposure limit of 65 dB Ld,,. . It is assumed that standard residential building construction in good condition will provide no less than 25 dB of exterior-to-interior noise level reduction when exterior doors and windows are closed. Therefore, exterior noise exposure would need to exceed 70 dB Lan for interior noise exposure to possibly exceed the County 45 dB Lan limit(i.e., 70 dB—25 dB =45 dB).Project-related traffic noise exposure due to haul trucks is not expected to exceed 66 dB Ldr,at the closest residences on East River Road. Therefore, project-related traffic noise exposure is not expected to exceed the applicable 45 dB Lan noise exposure criterion for the interior of these residences. Noise Exposure Increase Measured ambient noise exposure at the closest residences to the project site on East River Road was in the range of 67-69 dB Ldn(Site 4). The addition of project-related haul truck noise exposure at a level of 62 dB Ld„(with proposed optimized operating parameters)would be expected to increase the traffic-related noise exposure at this residence and others near this setback distance to approximately 68-70 dB Ldn.This increase of approximately I dB would not be considered significant based on the FICON guidelines presented above. The addition of project-related haul truck noise exposure at a level of 66 dB L&(without proposed optimized operating parameters)would be expected to increase the traffic-related noise exposure at the closest residences on East River Road by approximately 2-3 dB,or 70-71 dB L&. This noise exposure increase would be significant based on the FICON guidelines presented above. Sleep Disturbance/Probability of Awakening The ANSI/ASA 512.9-2008 Part 6 was used to estimate the probability of awakenings of existing residents in the project area with current conditions and for future conditions due to project- related haul truck operations. Current Conditions A total traffic volume of 182 project haul trucks was assumed to traverse a given section of East River Road in the project area during a typical 7-hour sleeping period(assumed to be'10 p.m.-5 a.m.).A given truck passby was assumed to produce an average event noise exposure level of 58 dB SEL within a residence 60 feet from the centerline of the roadway(83 dB exterior SEL).The probability of the residents located 60 feet from East River Road awakening at least once during the night from project haul truck noise was calculated to be approximately 93 percent.This probability Munn&Perkins Quarry Excavation Permit 3.4-14 ESA!211086 Draft EER April 201t