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J i of proper speeds and gear selection is extremely difficult to enforce as a mitigation measure. The BAC report indicates that the analysis of truck noise impacts will assume that truck drivers are operating vehicles in the "quietest manner possible". This analysis is not a conservative approach to evaluating noise impacts. This would seem to indicate that there has been an identified significant impact,and that mitigation measures are being implemented. D. The BAC report conducts an evaluation of increased noise levels due to the project. The analysis correctly utilizes the FICON procedure which indicates that if existing background noise levels exceed 65 dB, a 1.5 dB increase would be required to trigger a significant increase in noise levels. If existing background noise levels range between 60 dB and 65 dB, a 3 dB increase would be required to trigger a significant increase in noise levels. In addition, if existing background noise levels are less than 60 dB, a 5 dB increase would be required to trigger a significant increase in noise levels. That being said, if you review the measured background noise levels contained within the appendix to the report, the background hourly average (Leq) values during the 9:00 p.m. hour at Noise Measurement Sites 1, 3, 4 & 5; which represent distances between 40 feet and 60 feet from the East River Road centerline,the noise levels range between 62 dB and 68 dB Leq. Based upon the average measured truck passby noise level of 86 dB SEL, at a distance of 40 feet, and the predicted anticipated 66 truck trips during the 9:00 p.m. hour associated with the Munn Perkins plant expansion, the noise level associated with the additional truck trips would be 68.6 dB Leq. Therefore, the cumulative increase in truck traffic noise levels is expected to range between 3 dB and 7 dB Leq. So clearly during the start-up of the truck traffic, there would be a significant increase truck traffic noise levels. The report does not provide this conclusion. SPECIFIC COMMENTS ON THE BAC REPORT Criteria for Acceptable Noise Exposure 1. The report provides a discussion, on Page 6, that describes the effects of single event noise. The discussion centers around the potential for sleep disturbance, and utilizes the Federal Interagency Committee on Aviation Noise (FICAN) report which estimated a 5— 10%of the population is affected when interior SEL noise levels are between 65 and 81 dB,and few sleep awakenings (less than 5%) are predicted if the interior SEL is less than 65 dB. However, most recent research and procedures for evaluating sleep disturbance are based upon the American National Standards Institute (ANSI) which has developed procedures for evaluating the potential for sleep disturbance. The Procedure ANSI/ASA S12.9-2008 / Part 6 sets for the procedures for evaluating the potential for sleep disturbance. It establishes a threshold for a single event for which the A-weighted sound exposure level (ASEL) which occurs within a room at 50 dBA. The ANSI procedure calculates the probability of awakening based upon the interior mean 3