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Draft Environmental Impact Report Bernal Property Phase II Specific Plan EIR The locations of the noise monitoring locations, as shown in Figure 17, were as follows: . Location LT-l: 1-680. This measurement position is located approximately 165 feet east of the center of 1-680, in direct line-of-sight with the roadway. This location was selected to monitor noise levels generated by traffic along 1-680. The Ldn calculated from the data collected was 80 dBA. Measurement results are presented in Table 7. . Location L T-2: UPRR. This measurement position is located at a distance of about 25 feet south ofthe Union Pacific Railroad line, a location chosen to document noise levels generated by railroad operations at nearby noise sensitive uses. Traffic along 1- 680 dominated the noise environment in the absence of railroad operations. Maxi- mum noise levels generated during train passbys at this location were 90 to 95 dBA Lma<, with an average of about 12 passbys per day over the course of the monitoring period. The Ldn calculated from the noise data was about 72 dBA. Measurement results are presented in Table 8. . Location ST-l: Central Area. This measurement position is located at the eastern edge of the Phase 1 residential area on the western edge of Phase II sub-area 3 (the Grand Meadow area). This location was selected to measure ambient noise levels in areas that are shielded from the primary noise sources in the Plan area: 1-680, Bernal Avenue, and UPRR. Measurement results are presented in Table 9. . Location ST-2: Western Area. This measurement position is located on the west side of the noise berm along 1-680 in sub-area 11. This location was selected as a supplement to L T-1 to monitor noise levels west of 1-680, behind the berm. Measurement results are presented in Table 9. Table 9 Short-Term Noise Measurement Summary Noise Measurement Location Primary Noise and Time of Day Leq Lmax llo L50 L90 LdnJJ Source ST-1: Corner of Cotton Mill Way and Oak Vista Way 47 69 47 42 40 < 55 distant traffic noise 13:10 to 13:20 PM ST-2: -300 feet from the center of 1-680, 110 feet frorn center ofw. Lagoon 53 59 56 53 51 58 1-680 traffic noise Road, shielded from 1-680 by berm 14:20 to 14:30 PM Source: Illingworth & Rodkin, noise observations recorded October 6, 2005 33 Ldn noise levels are estimated based on L T and ST measurement results. 102