CCP 11-13-1995 - Laserfiche WebLink

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I I. STATE NOISE STANDARDS I Sound Level (dBA) Day (0700.2200) Night (2200-0700) I Noise Area General Land Classification Use Type L50 LIO L50 LIO 1 Residential 60 65 50 55 I 2 Commercial 65 70 65 70 3 Industrial 75 80 75 80 I Snurce. Minnesota Rules Parts 7030,0010 to 7030.0080, I During the 1994-95 legislative session, the Minnesota Statutes were revised to exempt from the state noise standards "an existing or newly constructed segment of a highway, provided that all reasonably available noise mitigation measures, as approved by the commissioners of the department of transportation and I pollution control agency, are employed to abate noise." The department oftransportation and the pollution control agency are currently in the process of developing criteria to define "reasonably available noise mitigation measures." The criteria being considered include: I 0 Resident desire for noise mitigation . Existing daytime and nighttime noise levels 1- 0 Change in noise levels associated with the project I -"" 0 Average noise level reduction with mitigation 0 Cost of mitigation per dBA reduction per residence protected I Potential Noise Imnacts and Miti~ation I Figures 1,2 and 3 present predicted noise levels along TH 96 based on the assumptions listed above and the alternative roadway cross sections shown in the figures. I Figure 1 compares predicted noise levels associated with tbe existing two-lane, roadway to noise levels associated witb a four-lane divided roadway. The four, lane divided roadway widens the road closer to adjacent receivers. However, tbe opposing travel lanes are moved furtber from tbe receivers. The net result I is a sligbt (less than I dBA) increase in noise levels adjacent to the road witb the four-lane divided roadway, The noise levels shown in Figure I are in excess of the state residential noise standard. Noise levels range I from approximately 72 dBA at the edge ofthe right of way to approximately 66 dBA at the homes adjacent to the road, The state residential standard is 65 dBA. This indicates that noise mitigation for the residential areas along TH 96 may be warranted, However, more detailed analysis including refinement of the I assumptions regarding traffic volumes and truck percentages and an evaluation relative to tbe criteria listed on page 6 is necessary before a final determination on the need for mitigation is made. I' - Tbe most effective means of noise mitigation is a noise barrier to block the line of sight between the roadway noise source and the adjacent receiver sites. Figures 2 and.g illustrate the effectiveness of alternative noise I 47