CCP 09-30-2002 - Laserfiche WebLink

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Regulatory Framework . The MPCA is the governmental regulatory agency responsible for implementing regulations controlling traffic noise in Minnesota. Minnesota State noise standards have been established specifically for daytime and nighttime periods. For residential land uses (identified as Noise Area Classification 1 or NAC-1), the Minnesota State standards for LIO are 65 decibels for daytime and 55 decibels for nighttime; the standards for Lso are 60 decibels for daytime and 50 decibels for nighttime. For parkland with no overnight uses (such as Cummings Park), NAC-l daytime standards apply to both daytime and nighttime noise levels. Minnesota Statute 116.07, Subd. 2a. states that municipal and county roads, except in the cities of Minneapolis and St. Paul, are exempt from state noise standards. All the roads near the proposed project site are county or city roads (with the exception ofI-694) and are therefore exempt from standards. State standards are included in this study for reference only and are depicted in Table 22. TABLE 22 MINNESOTA STATE NOISE STANDARDS MPCA State Noise Standards Land Use Code Day (7 a.m. -10 p.m.) dBA Night (10 p.m. -7 a.m.) dBA Residential NAC-1 LIO of 65 L50 of 60 LIO of 55 L5oof50 Commercial NAC-2 LIO of70 L50 of 65 LIO of 70 L5oof65 Industrial NAC-3 LIO of 80 L5oof75 LIO of 80 L5oof75 . Noise Level Monitoring Noise level monitoring is commonly performed during a noise study to document existing noise levels at selected receptor locations. Existing monitored noise levels can be used as a "baseline" against which future scenarios are compared. In addition, when studying future noise levels projected with computcr models, monitored noise levels are compared to modeled results for existing conditions to validate the computer modeling techniques and results. Existing noise levels were monitored at three sites (R2, R4 and R 7) in the project area on July 9, 2002, Monitoring site locations were chosen to represent areas of outdoor human activity, i.e., residential yards (Figure 16). Noise monitoring results are presented in Table 23. Monitoring results are presented along with the results of computer modeling for existing daytime noise conditions, The computer-modeled results are within . o to 2 decibels of the monitored levels; therefore, the computer model can be considered to be a valid predictor of future noise levels. Guidant Campus Master Plan Draft AUAR -49- September 2002