11 ATTACHMENT 04 - Laserfiche WebLink

- 16 - V. Evaluation of the Noise Exposures and Vibration Levels A. Exterior Noise Exposures To evaluate the on-site noise exposures against the City of Pleasanton Noise Element standards. the DNL.'s for the sun e3 lacations were calculated by decibel averaging of :he Lei's as they apps to the daily suhperiods of the DNL index. A nighttime weighting laeuir vVas applied to account for the increased human sensitivity to noise at night. Adjustments were trade to the measured noise levels to account for the difference in distance Netween the measurement locations and the various building setbacks. using methods established by the Highway Research Board. Ref (e). and Wyie Laboratories. Ref. (f). The DM_ formula is shown in Appendix B. The results of the calculations are shown in Appendix C. The calculations show that the existing noise exposure at measurement Location I 45 ft. from the centerline of Stanley Boulevard ranged were from 63. 64 and 65 dB DNL on days 1. 2 and 3. respectively. However. these noise exposures are a combination of both Stanley Boulevard traffic noise and rail noise. To segregate the two sources_ the information contained in Tables I. II and III watt extrapolated to Location 1 then subtracted from the total sound levels. the railroad noise exposures at Location I were 57. 59 and 60 dB DNL. The results of these caret lotions yielded noise exaosures of 62 dB DNL for each of the ihree measurement days from Stanley Boulevard traffic. Under future traffic conditions. the noise exposure from Stanle} Boulevard traffic -.s expected to increase to 65 dB DM... At the property lines if Lots 1 and 14 closest to Stanley Boulevard. the noise exposures are 63 and 66 dB DNL under existing and future traffic conditions. respectiyely. Thus. tae noise exposures will he up to 6 dB in excess of the City of Pleasanton Noise element in the most noise impacted rear and side yards.