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TOWN OF TRUCKEE <br />CANYON SPRINGS DRAFT EIR <br />NOISE <br />4.11-2 <br /> <br /> <br />while the Ldn and CNEL are measures of community noise. Each is applica- <br />ble to this analysis and defined as follows: <br />¤ Leq, the equivalent energy noise level, is the average acoustic energy con- <br />tent of noise for a stated period of time. Thus, the Leq of a time-varying <br />noise and that of a steady noise are the same if they deliver the same <br />acoustic energy to the ear during exposure. For evaluating community <br />impacts, this rating scale does not vary, regardless of whether the noise <br />occurs during the day or the night. <br />¤ Ldn, the Day-Night Average Level, is a 24-hour average Leq with a 10 dBA <br />“weighting” added to noise during the hours of 10:00 p.m. to 7:00 a.m. to <br />account for noise sensitivity in the nighttime. The logarithmic effect of <br />these additions is that a 60 dBA 24 hour Leq would result in a measure- <br />ment of 66.4 dBA Ldn. <br />¤ CNEL, the Community Noise Equivalent Level, is a 24-hour average Leq <br />with a 5 dBA “weighting” during the hours of 7:00 p.m. to 10:00 p.m. <br />and a 10 dBA “weighting” added to noise during the hours of 10:00 p.m. <br />to 7:00 a.m. to account for noise sensitivity in the evening and nighttime, <br />respectively. The logarithmic effect of these additions is that a 60 dBA 24 <br />hour Leq would result in a measurement of 66.7 dBA CNEL. <br />¤ Lmin is the minimum instantaneous noise level experienced during a given <br />period of time. <br />¤ Lmax is the maximum instantaneous noise level experienced during a given <br />period of time. <br /> <br /> <br />B. Regulatory Framework <br />The following section summarizes the regulatory framework related to noise, <br />including federal, State, and Town of Truckee plans, policies, and standards. <br />