EXHIBIT 4-1_55A_BRISTOL WIDENING EIS-EIR

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Iw1 Measurement Site 11 was located adjacent to an elementary school outdoor activity area 8 feet from the right -of -way. The barrier analysis assumed that the sensitive receptor vias located 10 feet behind a wall constructed at the right -of -way. As shown in Table 18, a 6 -foot barrier constructed at the right - of-way will be adequate to achieve acceptable noise levels. Measurement Sites 12, 12A, 13, and 13A were located north of St. Gertrude Place. Sites 12 and 12A represent front and back yard front line receptor locations respectively. Similarly, sites 13 and 13A represent front and back yard second line receptor locations. For alternatives 1 and 2, the house adjacent to sites 12 and 12A will be removed, increasing noise levels at site 13 (located 108 or 85 feet from the Bristol Street centerline for 104 feet from the centerline). Both first and second line rear yard receptors were sheltered by a wooden fence with visible gaps. The noise attenuation of the wooden fences was calculated to be 4 dBA. As shown in Table 18, the noise impacts at the rear yard activity areas do' not warrant additional mitigation. As shown in Table 18, the second line rear yard receptor (site 13A) would not require additional mitigation with any of the alternatives with the existing fence. However, because of the uncertain nature of the fence, future noise levels should be addressed without that fence. In that case, this second -line receptor would have future noise impacts and require noise walls as shown in Figure 19. The front yard noise impacts for the first line receptor (site 12) 'and for the O,,, second line receptor (site 13) when the first line house is removed, are typical impacts associated with a house facing a side street. Although a 6 -foot block ` wall would reduce noise impacts, a wall extending out to the comer would dw reduce the visibility of motorists on St. Gertrude Place and Bristol Street. Although the noise attenuation from a 6 -foot barrier placed at the right -of -way (60 feet from the centerline) in front of dwellings fronting on Bristol Street is evaluated in Table 18, construction of a wall may prove infeasible. For most of these dwellings, noise barriers will conflict with existing driveways, .,. pedestrian access, or reduce vehicular sight distances at comers. Construction of a non - contiguous wall would lower noise levels behind the wall but would reduce the effectiveness of the noise barrier such that the Caltrans minimum effectiveness criteria would not be met. Figure 19 depicts which residences appear to be noise impacted by future �.. traffic volumes projected for Bristol Street with or without each of the proposed project alternatives. Figure 19 also indicates whether front yard exterior impacts are anticipated, and where first and second line noise barriers .. may be constructed. Parcels affected by the preferred alternative are outlined for emphasis. The barriers proposed will mitigate noise below the federal .. IV -32