Laserfiche WebLink
0� OCTA I Santa Ana/Garden Grove Fixed Guideway Project <br />Noise and Vibration Technical Analysis Re-evaluation in Support of Minor Design Modifications <br />accounted for in the original noise and vibration analysis. <br />As originally evaluated for the approved LPA in the 2015 EA/EIR, it was assumed that the <br />streetcar transit vehicles will be equipped with vehicle warning horns, which will be sounded <br />when approaching the rail/roadway grade crossings. This assumption is also applicable to the <br />proposed modifications. Table D lists the noise levels associated with the vehicle warning <br />horns, and the distances from the modeled receivers to the original alignment and to the <br />proposed alignment. <br />Table D: Comparison of Originally -Approved LPA and Modified Project Warning Horn <br />Noise Levels <br />Receiver <br />Land <br />Use <br />Cat. <br />Original Alignment <br />Distance to Track <br />Centerline (ft) <br />Proposed <br />Alignment Distance <br />to Track Centerline <br />(ft) <br />Original <br />Alignment <br />Warning Horn <br />Noise Level <br />Proposed <br />Alignment <br />Warning Horn <br />Noise Level <br />Change in <br />Streetcar <br />Operations <br />Noise Level <br />R8 <br />3 <br />83 <br />92 <br />65 <br />65 <br />0 <br />R9 <br />3 <br />392 <br />401 <br />63 <br />63 <br />0 <br />R11 <br />3 <br />134 <br />134 <br />59 <br />59 <br />0 <br />R10 <br />2 <br />55 <br />55 <br />69 <br />69 <br />0 <br />R12 <br />2 <br />49 <br />49 <br />73 <br />73 <br />0 <br />R13 <br />2 <br />57 <br />60 <br />69 <br />69 <br />0 <br />Source: URS (February 2012) and HDR (June 2016). <br />COMBINED EFFECT (INCREASE IN SPEED AND ALIGNMENT SHIFT) <br />Table E provides a comparison between the noise levels calculated for the originally -approved <br />LPA and the proposed alignment shift. This table reflects the change in noise levels associated <br />with both the proposed increase in speed and the proposed change in centerline location <br />(alignment shift). The impacts for the currently proposed increase in speed combined with the <br />alignment shift are the same as those for the original LPA with the exception of at receivers R1 <br />(located within NSA 1), R4 (located within NSA 2), R7 (located within NSA 3), and R8 (located <br />within NSA 4). With the proposed modifications, receivers R1 and R4 would be exposed to <br />moderate noise impacts. At receiver R7 the noise level worsened from a moderate impact to a <br />severe impact as compared to the original LPA. At receiver R8 the noise level improved, as it <br />would be reduced from a severe impact under the original LPA, to a moderate impact under the <br />currently modified project. <br />Table E: Comparison of Originally -Approved LPA and Modified Project Train Operation <br />Noise Levels (Unmitigated) <br />Ll <br />Land <br />Existing <br />Noise <br />Predicted Project Only Noise Level <br />Ldn or Lday (d BA) <br />Approved <br />Revised <br />Project <br />Overall <br />Use <br />Level <br />Streetcar <br />Warning <br />Project <br />Project Impact <br />Impact <br />NSA <br />Rec. <br />Cat. <br />(d BA) <br />Ops <br />Horn <br />Crossing <br />O&M <br />Noise <br />(no mitigation) <br />(no mitigation) <br />1 <br />R1 <br />2 <br />53 <br />56 <br />N/A <br />N/A <br />N/A <br />56 <br />No Impact <br />Moderate <br />I mpact <br />Ll <br />