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4. ENVIRONMENTAL ANALYSIS r_ 4.5 NOISE Impact 4.5.3: Traffic associated with operation of the project would result in an increase in ambient noise levels on nearby roadways used to access the mine. This would be a potentially significant impact. ` Based on the traffic analysis prepared for this project,the proposed project would generate approximately 1,962 additional one-way vehicle trips per day during periods of maximum output (summer months). Haul trips by heavy trucks to and from the project site would account for almost all of this increase. Truck trips would typically begin as early as 6:00 AM but on some occasions would occur continuously on a 24-hour basis. These trips would be distributed over the local road network and would affect roadside noise levels. To assess the impact of project traffic on roadside noise levels, noise level projections were made .� using the Federal Highway Administration's(FHWA)Noise Prediction Model for those road segments that would experience the greatest increase in traffic volume(as determined in the traffic section of this report) and that pass by sensitive receptors. The results of the modeling effort are shown in Table 4.5-5. The traffic volumes used for the modeling effort are average morning weekday peak-hour volumes during periods when the mine is generating maximum output(summer)because that is when the project would generate the highest number of truck '- trips. Estimated noise levels shown in Table 4.5-5 correspond to a distance of approximately 50 feet from the centerline of applicable roadway segments, which is also the assumed distance to sensitive receptors. TABLE 45-5 EXISTING AND PROJECTED MORNING PEAK-HOUR TRAFFIC NOISE LEVELS ALONG LOCAL ROADWAYS Peak-Hour Noise Level,dBA,Leq ab rExisting Existing Plus Cumulative Cumulative Segment Plus Haul Haul Route Plus Haul Plus Haul No. Roadway Segment Existing Route Opt.l Opt.2 Route Opt.1 Route Opt.2 1 Koster Road south of Blewett Road 63.9 63.9 63.9 70.0 70.0 .. 2 Blewett Road east of Koster Road 63.1 63.1 63.1 67.7 67.7 3 Wetly Road north of Blewett Road 64,6 64.6 64.6 70.3 70.3 4 Wetly Road south of Blewett Road 65.4 65.4 65.4 70.2 70.2 5 Koster Road south of State Route 32 65.8 65.8 74.5 71.6 75.9 6 State Route 32 east of Koster Road 75.6 76.4 76A 833 833 7 State Route 32 west of Koster Road 75.4 76.1 77.1 833 835 8 Blewett Road east of Bird Road 68.9 77,7 75.0 78.7 76.8 a Noise levels were calculated using the FHWA Traffic Noise Prediction Model for weekday morning peak-hour conditions during periods of maximum production. Noise levels were calculated at roughly 50 feet from the centerline of the roadway. b For each of the roadway segments,the proportion of trucks and automobiles and their respective speeds differ for each road segment are based on the professional assumptions of Peters Engineering Group. SOURCE: Environmental Science Associates,2004 RMC Pacific vernalis Quarry Mining and Reclar tion Project 4.5-17 ESA/213015 Administrative Draft EDi Mmch 2004 r