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Noise Impacts to Off -Site Receptors Due to Project Generated Trips <br />A worst -case project generated traffic noise level was modeled utilizing The FHWA Traffic Noise <br />Prediction Model - FHWA-RD-77-108 was referenced to calculate the potential noise impact associated <br />with project generated traffic. Roadway parameters for the traffic model calculations include average <br />daily traffic volumes (ADTs), posted speeds, and vehicle distribution data as shown in Table 20. The <br />potential off -site noise impacts were calculated for the "existing" condition and the "existing plus project' <br />condition. <br />Table 20 <br />Project Average Daily Traffic Volumes and Roadway Parameters <br />Average Daily Traffic <br />Posted <br />Volume' <br />Travel <br />Site <br />Roadway <br />Segment <br />Speeds <br />Conditions <br />Existing Plus <br />Existing <br />Project <br />(MPH) <br />West of Flower <br />21,149 <br />21,720 <br />45 <br />Hard <br />Sunflower <br />StreeUSakioka Drive <br />Avenue <br />East of Flower <br />45 <br />StreeUSakioka Drive <br />19,620 <br />20,634 <br />Hard <br />Flower <br />Street <br />North of Sunflower Avenue <br />9,773 <br />9,836 <br />40 <br />Hard <br />Vehicle Distribution (Heavy Mix)Z <br />Daytime % <br />Night % <br />(7 AM - 7 <br />Evening % <br />(10 PM - 7 <br />Motor -Vehicle Type <br />PM) <br />(7 PM - 10 PM) <br />AM) <br />Automobiles <br />75.54 <br />14.02 <br />10.43 <br />Medium Trucks <br />48.00 <br />2.00 <br />50.00 <br />Heavy Trucks <br />48.00 <br />2.00 <br />50.00 <br />As shown, modeled Existing traffic noise levels range between 72.07-75.37 dBA CNEL and the <br />modeled Existing Plus Project traffic noise levels range between 72.08-75.42 dBA CNEL at the right-of- <br />way of each modeled roadway segment. Noise level increases associated with project generated traffic <br />would be considered significant if noise levels were greater than the levels shown previously in Table <br />16. A shown below in Table 21 all modeled roadway segments are calculated to have noise level <br />Increases of approximately 0.01 to 0.1 dBA CNEL. Therefore, the increase in the noise level on area <br />roadways would be less than significant. <br />Transportation Noise Impacts to the Project <br />The City of Santa Ana General has adopted interior and exterior noise level criteria for residential, <br />institutional, and open space land uses. As shown previously in Table 16, exterior noise levels up to 65 <br />dBA CNEL and interior noise levels of 45 dBA CNEL are considered acceptable noise levels for <br />residential use. Exterior areas are defined as private yards of single-family homes, park picnic areas, <br />school playgrounds, common areas, private open space, such as atriums on balconies, shall be <br />excluded from exterior areas provided that sufficient common area is included within the project. Interior <br />noise level requirements contemplate a closed window condition. Mechanical ventilation system or <br />other means of natural ventilation shall be provided per the Uniform Building Code. <br />Legacy Sunflower Apartments Page 79 <br />Mitigated Negative Declaration — March 14, 2019 <br />751-165 <br />