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South Coast Technology Center Project <br />CEQA Exemption 15183 <br />hour traffic, vehicle speeds and heavy truck volumes are often low and free -flowing traffic <br />conditions just before or after rush hour often yield higher noise levels. <br />Table 4.13-1 <br />Noise Measurements <br />Site <br />Location <br />Leq (dBA) <br />Lmin (dBA) <br />Lmax (dBA) <br />Time <br />No. <br />1 <br />In front of 3626 South Marine Street multifamily <br />72.6 <br />51.2 <br />87.0 <br />11:07 a.m. <br />residential use <br />Near 3388 Corte Cassis residential use, <br />2 <br />approximately 200 feet west of the Fairview Road <br />68.2 <br />48.5 <br />86.6 <br />11:39 a.m. <br />and Sunflower Avenue intersection <br />In front of Calvary Chapel bookstore, <br />3 <br />approximately 200 feet east from the Lake Center <br />60.3 <br />52.3 <br />81.0 <br />12:07 p.m. <br />Drive and Susan Street intersection <br />Notes: <br />dBA = A -weighted decibels, Leq = Equivalent Sound Level; Lm;n = Minimum Sound Level; Lmax = Maximum Sound Level, Peak = <br />Highest Instantaneous Sound Level <br />Source: Michael Baker International, May 18, 2023. <br />Noise Sensitive Receptors <br />Noise -sensitive land uses are generally considered to include those uses where noise exposure <br />could result in health -related risks to individuals, as well as places where quiet is an essential <br />element of their intended purpose. Residential dwellings are of primary concern because of the <br />potential for increased and prolonged exposure of individuals to both interior and exterior noise <br />levels. Additional land uses such as parks, historic sites, cemeteries, and recreation areas are <br />considered sensitive to increases in exterior noise levels. Schools, churches, hotels, libraries, and <br />other places where low interior noise levels are essential are also considered noise -sensitive land <br />uses. <br />The nearest sensitive receptor to the Project Site is an existing institutional use (Calvary Chapel <br />High School) located approximately 100 feet to the east of the Project Site. The nearest existing <br />residential uses are located approximately 800 feet to the south in the City of Costa Mesa and <br />850 feet to the east within the City of Santa Ana. <br />SIGNFICANCE CRITERIA AND METHODOLOGY <br />Construction and Operational Noise Standards <br />Neither the City of Santa Ana nor the City of Costa Mesa have a quantitative threshold that applies <br />to noise levels at active construction sites. To evaluate whether the Project would generate <br />potentially significant temporary construction noise levels at off -site sensitive receiver locations, <br />a construction -related noise level threshold from the from the FTA Transit Noise and Vibration <br />Impact Assessment criteria will be used. The FTA provides reasonable criteria for assessing <br />construction noise impacts based on the potential for adverse community reaction. For residential <br />uses, the daytime noise threshold is 80 dBA Leq averaged over an 8-hour period (Leq (8-hr)) and <br />the nighttime noise threshold is 70 dBA Leq (8-hr). In compliance with the SAMC, construction <br />would not occur during the noise -sensitive nighttime hours. For the purposes of this analysis, the <br />lowest, most conservative construction noise level threshold of 80 dBA Leq is used as an <br />acceptable threshold for construction noise at the nearby sensitive receptor locations. Since this <br />construction -related noise level threshold represents the energy average of the noise source over <br />July 2024 Page 78 <br />