EXHIBIT 4-2_55A_BRISTOL WIDENING TECHNICAL STUDIES

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Measurement site 10 was selected at the Mater Dei High School track field which lies adjacent to Bristol Street, just south of Edinger Avenue. The track is raised 3.5 feet above grade and lies seven feet from the right -of -way. The measurement was taken when this field was in use to reflect the greatest noise impact on sensitive receptors. The measurement site was located at the ` edge of the track and separated from the roadway by a chain link fence. A bus stop on Bristol Street, located directly in front of this track/field, will contribute to the ambient noise level at this site. Measurement site 11 was selected at the Jose Andres Sepulveda Elementary School on the west side of Bristol Street, opposite Mater Dei High School. The site was at a playground for younger children, situated between a chain link fence at the right -of -way and the school media center. The measurement was taken 16 feet from the right -of -way. The media center, the closest building to the roadway, is situated 52 feet from the right -of -way. Current plans include the relocation of this playground as a safety 1 precaution (to increase the distance to Bristol Street). Measurement sites 12 and 12A are located at an SFD on the north- east corner of Bristol at St. Gertrude. Site 12 was taken in the front yard, 18 feet from the Bristol Street right -of -way. There is a stop sign on St. Gertrude in front of this site where vehicles queue during the peak hour. Site 12A was situated in the rear yard at an exterior laving area, 30 feet from the right -of -way. The yard is enclosed with a 5.5 foot wooden fence that provides some noise attenuation. Measurement sites 13 and 13A are located at an SFD which is one house removed from the corner of Bristol at St. Gertrude. This residence is considered a second line receptor since the corner house provides shielding which would be eliminated if the house was removed after right --of -way acquisition. Site 13 is located in the front yard at 70 feet from the Bristol Street right -of- way. Site 13A is located in the rear yard at an exterior activi- ty area 89 feet from the Bristol Street right- of--way. A 5.5 foot high wooden fence separates this rear yard from the corner resi- dential lot. From Table 4 -3, it can be seen that noise levels at measurement sites 13 and 13A are significantly lower than levels at the first line receptor. Noise Modeling Results Noise from motor vehicles is generated by the engine vibrations, the interaction between the tires and the road, and the exhaust system. Reducing the speed of motor vehicles reduces the noise exposure of listener's inside the vehicle and those located adja- cent to the roadway. The highway traffic noise prediction model developed by the Federal Highway Administration (RD --77 --108) and currently being 4 -10