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OCTA I Santa Ana/Garden Grove Fixed Guideway Project <br />FNNoise and Vibration Technical Addendum <br />Table G: Comparison of the 30 Percent Design and 60 Percent Design Train Operation <br />Noise Levels (Unmitigated) <br />NSA <br />Rec. <br />Land <br />Use <br />Cat. <br />Existing <br />Noise Level <br />(d BA) <br />30% Design 60% Design <br />Overall Project Overall Project <br />Noise Noise <br />30% Design Project <br />Impact <br />(no mitigation) <br />60% Design Project <br />Impact <br />(no mitigation) <br />Impact <br />R1 <br />2 <br />53 <br />56 <br />56 <br />Moderate Impact <br />Moderate Impact <br />1 <br />R2 <br />2 <br />52 <br />52 <br />51 <br />No Impact <br />No Impact <br />63 51 <br />R3 <br />2 <br />51 <br />52 <br />52 <br />No Impact <br />No Impact <br />2 <br />R4 <br />2 <br />50 <br />52 <br />52 <br />No Impact <br />No Impact <br />55 <br />R5 <br />2 <br />51 <br />54 <br />54 <br />Moderate Impact <br />Moderate Impact <br />3 <br />R6 <br />2 <br />52 <br />59 <br />59 <br />Moderate Impact <br />Moderate Impact <br />R7 <br />2 <br />50 <br />64 <br />64 <br />Severe Impact <br />Severe Impact <br />R8 <br />3 <br />52 <br />65 <br />65 <br />Moderate Impact <br />Moderate Impact <br />4 <br />R9 <br />3 <br />52 <br />64 <br />64 <br />Moderate Impact <br />Moderate Impact <br />5 <br />R11 <br />3 <br />46 <br />60 <br />60 <br />Moderate Impact <br />Moderate Impact <br />6 <br />R10 <br />2 <br />53 <br />69 <br />69 <br />Severe Impact <br />Severe Impact <br />7 <br />R12 <br />2 <br />50 <br />1 73 <br />1 72 1 <br />Severe Impact I <br />Severe Impact <br />8 <br />R13 <br />2 <br />55 <br />69 <br />68 <br />Severe Impact <br />Severe Impact <br />9 <br />R15 <br />2 <br />67 <br />66 <br />66 <br />Moderate Impact <br />Moderate Impact <br />10 <br />R14 <br />2 <br />58 <br />64 <br />64 <br />Severe Impact <br />Severe Impact <br />Source: HDR (June 2016 and February 2017). <br />The following noise attenuation features that were previously identified in the June 2016 <br />memorandum would be required to reduce the project's severe impacts: <br />1. Wayside Noise Barriers <br />The FTA Manual indicates that the shielding attenuation provided by a wayside noise barrier <br />for the first row receptors would be 4.5 dBA. The 2016 noise analysis identified the need for <br />noise barriers for receptor locations R7, R10, R12, R13, and R14. Table H lists the train <br />noise levels for the 60% design after the wayside noise barrier has been implemented. <br />Receivers R7 and R14 are reduced to moderate after the implementation of the proposed <br />design feature. Attachment D shows the locations and heights for the proposed barriers. <br />Table H: 60 Percent Design Noise Levels — After Wayside Noise Barrier Design Features <br />NSA <br />Rec. <br />Land <br />Use <br />Cat. <br />Existing <br />Noise <br />Level <br />(d BA) <br />Predicted Project Only Noise Level <br />Ldn or Lday (d BA) <br />Impact <br />Overall <br />Streetcar Audible Project <br />Ops Warning Crossing O&M Noise <br />3 <br />R7 <br />2 <br />50 <br />59 <br />N/A N/A <br />N/A <br />59 <br />Moderate Impact <br />6 <br />R10 <br />2 <br />53 <br />52 <br />63 51 <br />N/A <br />64 <br />Severe Impact <br />7 <br />R12 <br />2 <br />50 <br />53 <br />67 49 <br />N/A <br />68 <br />Severe Impact <br />8 <br />R13 <br />2 <br />55 <br />52 <br />63 44 <br />N/A <br />63 <br />Severe Impact <br />10 <br />R14 <br />2 <br />58 <br />53 <br />N/A N/A <br />59 <br />60 <br />Moderate Impact <br />Source: URS (February 2012) and HDR (February 2017). <br />VJ <br />