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J <br /> located in a depression. In addition, since the noise measurement data <br /> used to extrapolate the asphalt plant operations were due to daytime <br /> asphalt plant operations, and were collected at a distance of over 2,000 <br /> feet from the plant, the expected nighttime noise levels, due to <br /> atmospheric conditions could increase by as much as 5 dBA to 10 dBA. <br /> The BAC staff are aware of the effects of atmospheric conditions during <br /> nighttime conditions. Therefore, we do not believe that the asphalt batch <br /> plant noise levels have accurately been identified. An accurate method for <br /> evaluating asphalt plant noise levels is to run the plant during the <br /> nighttime hours, and collect noise level data during the operations. This <br /> would provide an accurate representation of potential noise impacts. At <br /> the very least, reference noise level measurements of the asphalt plant <br /> should have been conducted. These reference measurements could have <br /> been used to generate noise contours associated with the operations. The <br /> noise level data is entered into a model which can account for prevailing <br /> wind direction, wind speed, temperature, atmospheric conditions and <br /> topography. <br /> • The report only evaluates the plant operations at the residences to the east. <br /> However, there are residences closer to the project site located along E. <br /> River Road. Although it is true that the noise environment at those <br /> residences will be dominated by truck traffic; the time periods between <br /> truck passbys may be dominated by noise associated with the asphalt plant <br /> operations. A detailed noise contour associated with the asphalt plant <br /> operations should be developed which shows the potential noise impacts at <br /> all receivers. <br /> • Sleep disturbance during individual truck passages, with windows closed <br /> are considered less than significant. The analysis of sleep disturbance on <br /> page 31 appears to be flawed. The American National Standards Institute <br /> (ANSI) has developed procedures for evaluating the potential for sleep <br /> disturbance. The Procedure ANSI/ASA S12.9-2008 / Part 6 sets for the <br /> procedures for evaluating the potential for sleep disturbance. It establishes <br /> a threshold for a single event for which the A-weighted sound exposure <br /> levet (ASEL) which occurs within a room at 50 dBA. The ANSI <br /> procedure calculates the probability of awakening based upon the interior <br /> mean SEL and the number of events which occur during the nighttime <br /> hours(10:00 p.m.—7:00 am.). The BAC report indicates that there would <br /> only be a 5%probability of awakening. However,the ANSI procedure for <br /> estimating the probability of awakening calculates a 97% probability of <br /> awakening, based upon an exterior SEL of 79 dBA and 182 truck trips <br /> during the nighttime period, as indicated in the BAC report. This is <br /> clearly a major difference in the overall analysis. <br /> • Project truck traffic increase in hourly noise levels is considered to be less <br /> than significant. Based upon the BAC report, the project could typically <br /> 9 <br />