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HARBOR BLVD. MIXED USE TRANSIT CORRIDOR PLAN FINAL FIR <br />CITY OF SANTA ANA <br />5. Environmental Analysis <br />NOISE <br />The traffic noise levels for this project were estimated using the Federal Highway Administration (FHWA) <br />Highway Traffic Noise Prediction Model (RD -77 -108). The FHWA model predicts noise levels through a <br />series of adjustments to a reference sound level. These adjustments account for distances from the roadway, <br />traffic flows, vehicle speeds, car /truck mix, length of exposed roadway, and road width. The distances to the <br />70, 65, and 60 CNEL contours for selected roadway segments in the vicinity of proposed project site are in <br />Appendix G. Tables 5.9 -7 and 5.9 -8 compare the noise levels at 100 feet from the centerline of each roadway <br />segment without and with the project for existing and 2035 conditions. <br />As discussed previously (see Table 5.9 -1), changes of 3 dBA are barely perceptible to the average human ear, <br />and changes of 5 dBA are readily perceptible. A noise impact may occur if three conditions are met: (1) there <br />is a noise increase of 5 dB or more from existing conditions, (2) project related traffic noise is greater than 1 <br />dBA, and (3) the CNEL is 65 dBA or greater in the vicinity of noise - sensitive land uses. <br />Existing Conditions <br />Table 5.9 -7 shows the projects noise increases over existing conditions without and with implementation of <br />the project. Traffic noise increases due to the project range from -1.6 to 0.8 dBA. The reduction in noise is <br />caused by a reduction in traffic volumes on some of the segments due to changes in land uses and the <br />corresponding trip generation at some areas of the Harbor Corridor Plan. The greatest noise increase of 0.8 <br />dBA would occur on Edinger Avenue from Fairview Street to Harbor Boulevard. The calculated noise <br />increases of up to 0.8 dBA at study area roadways due to the project would not result in a perceivable noise <br />increase at receptors along roadways. <br />Table 5.9 -7 Project - Related Traffic Noise, Existinq Conditions <br />Roadway <br />Segment <br />CNEL at 100 feet (dBA) <br />Increase above <br />Existing <br />(dBA) <br />No Project <br />With Project <br />Harbor Blvd. <br />Trask Ave. to Westminster Ave. <br />71.4 <br />71.1 <br />-0.3 <br />Harbor Blvd. <br />Westminster Ave. to Hazard Ave. <br />71.1 <br />70.7 <br />-0.4 <br />Harbor Blvd. <br />Hazard Ave. to First St. <br />71.2 <br />70.9 <br />-0.3 <br />Harbor Blvd. <br />First St. to McFadden Ave. <br />71.1 <br />71.1 <br />0.0 <br />Harbor Blvd. <br />McFadden Ave. to Edinger Ave. <br />71.0 <br />71.3 <br />0.3 <br />Harbor Blvd. <br />Edinger Ave. to Warner Ave. <br />70.5 <br />70.6 <br />0.1 <br />Harbor Blvd. <br />Segerstrom Ave. to MacArthur Blvd. <br />70.5 <br />70.4 <br />-0.1 <br />Westminster Ave. <br />Newhope St. to Harbor Blvd. <br />68.4 <br />68.5 <br />0.1 <br />Westminster Ave. <br />Fairview St. to Harbor Blvd. <br />67.8 <br />67.7 <br />-0.1 <br />1st Street <br />Newhope St. to Harbor Blvd. <br />67.2 <br />67.5 <br />0.3 <br />1st Street <br />Fairview St. to Harbor Blvd. <br />69.3 <br />69.5 <br />0.2 <br />McFadden Ave. <br />Newhope St. to Harbor Blvd. <br />65.8 <br />66.1 <br />0.3 <br />McFadden Ave. <br />Fairview St. to Harbor Blvd. <br />67.0 <br />66.4 <br />-0.6 <br />Edinger Ave. <br />Newhope Ave. to Harbor Blvd. <br />66.0 <br />66.1 <br />0.1 <br />Edinger Ave. <br />Fairview St. to Harbor Blvd. <br />1 67.5 <br />1 68.3 <br />1 0.8 <br />Source. FHWA Highway Traffic Noise Prediction Model based on traffic volumes provided by IBI Group 2013. <br />October 2014 Page 5.9 -9 <br />