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Predicted traffic noise levels were calculated for the segment of Grant Line Road along which Grant Line Village is located under future buildout conditions(2025)using the FHWA Traffic Noise Prediction Model.3 Input data used in the model included average daily traffic levels for nearby roads,day/night percentages of autos and medium and heavy trucks,vehicle speeds,ground attenuation factors,and road widths.Input information was based on the traffic analyses prepared for the project(Section 4.11,"Transportation')(TJKM 2004).Predicted traffic noise levels for this segment of Grant Line Road are presented in Table 4.13-10. _ Table 4.13-10 Predicted Cumulative Traffic Noise Levels on Grant Line Road at Grant Line Village Noise Level(dBA CNEL)50 Feet from Centerline of Near Travel Lane Existing Noise Cumulative+Project Exceedance of 60 Exceedance of 65 Existing Road Segment along With 7-foot dBA LdrJCNEL Existing Sensitive Receptors Level (Year and Sound Wall a without Sound dBA dCNEL with (dBA LadCNEL) without Sound Wall Barrier? Sound Barrier? Grant Line Road along existing Grant Line Village 71.29 71.04 64.32 Yes No (south side of road)' Note:Based on 2025 cumulative traffic conditions(year 2025 base case plus full buildout of the College Park project).Traffic noise levels were modeled using the FHWA Traffic Noise Prediction Model,based on traffic information from the project traffic analysis. Refer to noise model input/output information on file at SJCCDD for more detailed information. 'Noise walls were modeled at a height of 7 feet unless otherwise noted. -- Source:Data compiled by EDAW in 2004 As indicated in Table 4.3-10, existing traffic noise at Grant Line Village would decrease slightly under J cumulative plus project conditions(year 2025)(from 71.29 to 71.04 dBA Lda/CNEL). The reasons for this slight reduction are twofold: Grant Line Road would be widened from two to four lanes,thus distributing the traffic to multiple lanes and decreasing the existing amount of traffic in the travel lane closest to the Grant Line Village residences; and a frontage road is proposed under the College Park project between Grant Line Road and Grant Line Village that would increase the distance between the nearest travel lane of Grant Line Road and the property line of Grant Line Village.Because traffic noise at Grant Line Village would go down slightly under cumulative - plus project conditions(year 2025),a less-than-significant impact would occur. Mitigation Measure 4.13-3: Noise—Increased Traffic Noise. - The project applicants shall implement the measures identified below. Before occupancy of the first residence at College Park,a noise barrier shall be constructed by the College Park developers between the five existing residences located on the north side of Grant Line Road between Central Parkway and the Alameda County line(Receptor 14 in Figure 4.13-2)and the northern travel lane of Grant Line Road.The noise barriers may consist of a wall,berrr� or combination thereof.The exact location, height, and character of the noise barrier shall be detemuned by a noise consultant approved by the County. The sound barrier shall reduce outdoor noise levels at the center of the front yards of the five existing residences to below 65 dBA Ldr,/CNEL. If Grant Line Road is widened at this location subsequent to construction of the sound barrier but before removal of the five residences under Specific Plan II,the sound barrier shall be relocated,as required. If the five existing residences are removed under Specific Plan II before ;Traffic noise impacts on existing noise-sensitive uses are determined based on existing traffic conditions with and without implementation of the proposed project.This is compared with traffic noise impacts on proposed noise-sensitive uses that are determined based on cumulative traffic conditions with and without implementation of the proposed project. EDAW College Park at Mountain House Specific Plan III Draft EIR Noise 4.13.24 San Joaquin County