EXHIBIT 4-2_55A_BRISTOL WIDENING TECHNICAL STUDIES

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Three of the locations monitored (measurement sites 9, 12A, and 13A) were located at rear yard activity areas and do not require additional mitigation. The front of the dwelling at location 7 is on the right -of -way with the front entrance exiting onto the sidewalk. There is no room to construct a wall at this location. The remaining eleven locations that exceed the federal exterior noise criteria with at least one of the alternatives are dis- cussed in further detail below. For all eleven locations, the proposed Bristol Street right -of -way is 120 feet and the noise barrier is located 60 feet from the roadway centerline. All calculations assume level terrain (except at Mater Dei High School), and typically address conditions located 6 feet from the front -or back of the house (to represent activity areas). Measurement site 1 was in the front yard of a single family dwelling located north of Santa Clara Avenue. All three alterna- tives propose to remove this dwelling. Measurement site 2 was located adjacent to an outdoor activity area in an elementary school playground, 23 feet from the right- of-way. Alternatives 1, 2, and 3 assume that the existing 23 feet remains between the right -of -way and play area. As shown in Table 4 -9, a 6 -foot barrier constructed at the right -of -way will be adequate to reduce noise levels to acceptable levels. Measurement site 3 was at a multi - family dwelling complex and a common recreational area south of Santa Clara Avenue. All three alternatives propose to remove this dwelling. Measurement site 4 was located at the Rancho Santiago Community College Campus near the entrance to the auditorium. An existing 3 --foot wall located near the right --of -way would be removed for alternative 3. The distance between the measurement location and the Bristol Street centerline for alternatives 1, 2, and 3 are 127, 129, and 109 feet, respectively. As shown in Table 4 -9, a 6 -foot noise barrier constructed at the right -of --way would reduce the projected noise levels below 67 Leq. However, a 6 -foot wall is not recommended since it may have an adverse aesthetic impact on the campus. Measurement site 5 was located in the front yard of a single family residence located north of Civic Center Drive, near 9th Street. The residence will be removed with alternatives 1 and 2. The measurement location for alternative 3 is located 66 feet from the Bristol Street centerline (6 feet from the right -of-- way). Table 4 -9 shows that a 6 -foot noise barrier constructed in front of the residential complex would provide adequate noise attenuation. However, a contiguous noise barrier is not recom- mended since it would restrict pedestrian and vehicular access. Measurement site 5 was located in the front yard of a single family residence located south of Civic Center Drive. Tine [ 4 -21 l