3_Exhibit B - Laserfiche WebLink

4. Environmental Setting, Impacts, and Mitigation Measures J. Noise TABLE 4.J-6 (Continued) SUMMARY OF TRAFFIC NOISE MODELING RESULTS (EXISTING/EXISTING PLUS PROJECT) NOISE EXPOSURE (LDN) AT 100 FEET FROM ROADWAY CENTERLINEa,b General Plan Amendment and Rezonings 4.J-25 ESA / 210016 Draft Supplement EIR September 2011 Roadway Segment Existing (A) Existing plus Project (B) Change (B-A) Significant? Vineyard West of Bernal 56 55 -1 No Sunol North of Valley 63 61 -2 No Sunol South of Valley 64 61 -3 No Junipero Street East of Sunol 54 51 -3 No Valley West of Sunol 57 56 -1 No a Noise levels were calculated using the FHWA-RD-77-108 Traffic Noise Prediction Model for peak-hour conditions derived from average daily traffic levels. Noise levels were calculated at 100 feet from the centerline of the roadway. b The average vehicle speed varies for individual segments between 25 mph and 45 mph, based on roadway classification. The vehicle mix consists of 98 percent automobiles, 1 percent medium trucks, and 1 percent heavy trucks for neighborhood arterial roads and 96 percent automobiles, 2 percent medium trucks, and 2 percent heavy trucks for major arterial roads. The thresholds of significance include a 5+ dB increase in project-related traffic noise exposure or a project-related increase in traffic noise exposure that would cause overall traffic noise levels to exceed the applicable 60dBLdn standard for single-family land uses or 65dBLdn standard for multi-family land uses. Each roadway segment was reviewed via aerial photo to identify the existence of residential uses, existing noise- mitigating construction (i.e., noise barriers) for these uses, and to determine if project-related noise increases could exceed the established significance criteria. A significant noise impact was established for those roadway segments where project-related noise increases would be 5+ dB or where the project-related increase could cause noise exposure to exceed the applicable 60/65 dB Ldn noise exposure limit in residential recreation areas. SOURCE: Environmental Science Associates, 2011 The City is expected to repave all arterial roadways with noise-attenuating pavement in the future. It is expected that the sections of Hopyard Road and Stoneridge Drive highlighted in Table 4.J-6 would be included for this treatment. However, the timing of this paving is unknown, and existing noise-sensitive uses on these roadway segments may be impacted prior to its completion. Therefore, this impact is considered potentially significant. Mitigation Measure 4.J-5a would mitigate impacts of the rezoning to off-site sensitive receptors to a less than significant level. Methods for reducing off-site noise from project related traffic may include repaving with noise attenuating pavement, new windows at existing sensitive receptors, sound walls, or other measures. Studies have found that the application of noise-attenuating pavements produces typical noise level reduction in the range of 3-5 dB over traditional asphalt paving (Bollard and Brennan, 1999). This effort would more than account for the 1 dB increase produced by implementation of the project. Mitigation Measure 4.J-5a: Prior to prior to PUD approval a potential site for rezoning would add traffic noise in exceed of 55dBA described in Table 4.J-6, the project applicant shall conduct an off-site noise study to determine the project contribution to off-site roadway noise and contribute its fair-share to mitigate the established noise impact. Further, as shown in Table 4.J-6, developments adjacent to several of the studied roadways may experience traffic noise exposure in excess of 65 dB. Given a worst-case exterior-to-interior noise level reduction of 20 dB provided by project buildings, interior noise exposure could be 45 dB Ldn or higher within some project building. Development on the potential sites for rezoning would be subject to Title 24 of the California Code of Regulations, which requires an interior noise exposure of 45 dB Ldn/CNEL or less within any habitable room and requires an acoustical