CCP 01-21-2003 - Laserfiche WebLink

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I I. I I I I I I I .. I I I I I I -. I I Noise Level Monitorin!! Noise level monitoring is commonly performed during a noise study to document existing noise levels at selected receptor loeations. 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 computer models, monitored noise levels are compared to modeled results for existing eonditions to validate the eomputer modeling techniques and results. Existing noise levels were monitored at three sites (Rl, R4 and R7) in the project area on July 9,2002. Monitoring site locations were chosen to represent areas of outdoor human aetivity, i.e., residential yards (Figure 14). 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 noisc lcvels. Noise Modelini; Methodologv Traffic noise impacts were assessed by modeling noise levels at "sensitive" receptor sites (i.e., existing and future residences) likely to be most affected by changes in traffic volumes and roadway alignment resulting from construction of the proposed project. Eight noise modeling receptors (Rl - R8) were selected at existing residential properties in the project area to represent those sites most sensitive to potential project-related traffic noise impaets (Figure l4). Modeling was also performed for Cummings Park, which is located north of the Guidant campus and is representcd by R9. All receptor sites are classified within the definition of State of Minnesota Noise Area Classification One (NAC-l). Noise modeling was done using the noise prediction program "MINNOISE," a version of the FHWA noise model "STAMINA" adapted by MnlDOT and approved by the MPCA. This model uses vehicle numbers, spced, class of vehicle, and thc typical characteristics of the roadway being analyzed. The computations for the proposed improvements were based on existing and projected traffic volumes, existing and proposed traffic speeds, and vehicle class percentages. Projected traffic volumes for peak daytime and nighttime hours one year after completion of the full build out scenario (i.e., year 2020) were used to predict future noise levels. Noise Modeling Results Noise modeling results for existing (2002) conditions and for the year 2020 are presented in Tables 23 and 24. Both daytime and nighttime L[o and Lso are shown for the existing (2002) condition and for year 2020 with the two project altematives: No-Build and Build. Guidant Campus Master Plan Final AUAR and Mitigation Plan - 50- January 2003