T.H. 100 Reconstruction in St. Louis Park Environmental Assessment. Appendix C Traffic Noise Analysis Report

Transcription

1 T.H. 100 Reconstruction in St. Louis Park Environmental Assessment Appendix C Traffic Noise Analysis Report

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3 Highway 100 Reconstruction (State Project Number: ) July 2012 Prepared For: Minnesota Department of Transportation Metro District Prepared By: HDR Engineering, Inc Minneapolis

4 Highway 100 Reconstruction Project Traffic Noise Analysis Report The purpose of this analysis is to evaluate and document the effect of the proposed State Project Highway 100 Reconstruction Project on traffic generated noise levels. This analysis includes modeled traffic noise levels for existing (2011) and future (2030) No Build and Build conditions. This report is organized into the following sections: Introduction (Background Information) Analysis Methodology Modeling Results Noise Mitigation Evaluation o Noise Barrier Evaluation o Other Noise Mitigation Considerations Conclusions Introduction Noise is defined as any unwanted sound. Sound travels in a wave motion and produces a sound pressure level. This sound pressure level is commonly measured in decibels. Decibels (db) represent the logarithm of the ratio of a sound energy relative to a reference sound energy. For highway traffic noise, an adjustment, or weighting, of the high and low pitched sound is made to approximate the way that an average person hears sound. The adjusted sound levels are stated in units of A weighted decibels (dba). A sound increase of 3 dba is barely noticeable by the human ear, a 5 dba increase is clearly noticeable, and a 10 dba increase is heard as twice as loud. In Minnesota, traffic noise impacts are evaluated by measuring and/or modeling the traffic noise levels that are expected to be exceeded 10 percent and 50 percent of the time during the hours of the day and/or night that have the loudest traffic noise levels. These level descriptors are identified as the L 10 and L 50 levels, respectively. The L 10 level is the noise level that is exceeded for a total of 10 percent, or 6 minutes, of an hour. The L 50 level is the noise level that is exceeded for a total of 50 percent, or 30 minutes, of an hour. July Highway 100 Reconstruction Project

5 Table 1 provides a rough comparison of the noise levels of some common noise sources. TABLE 1 DECIBEL LEVELS OF COMMON NOISE SOURCES Sounds Pressure Level (dba) Noise Source 140 Jet Engine (at 75 feet) 130 Jet Aircraft (at 300 feet) 120 Rock and Roll Concert 110 Pneumatic Chipper 100 Jointer/Planer 90 Chainsaw 80 Heavy Truck Traffic 70 Business Office 60 Conversational Speech 50 Library 40 Bedroom 30 Secluded Woods 20 Whisper Source: A Guide to Noise Control in Minnesota, Minnesota Pollution Control Agency, and Highway Traffic Noise, FHWA, Along with the volume of traffic and other factors (e.g. topography of the area and vehicle speed) that contribute to the loudness of traffic noise, the distance of a receptor from a sound s source is also an important factor. Sound level decreases as distance from a source increases. A rule of thumb regarding sound level decrease due to increasing distance from a line source (roadway) that is commonly used is: beyond approximately 50 feet from the sound source, each doubling of distance from the line source over hard ground (such as pavement or water) will reduce the sound level by 3 dba, whereas each doubling of distance over soft ground (such as vegetated or grassy ground) results in a sound level decrease of 4.5 dba. Minnesota state noise standards have been established by the Minnesota Pollution Control Agency (MPCA) for daytime and nighttime periods. For residential land uses (identified as Noise Area Classification 1 or NAC 1), the Minnesota State standards for L 10 are 65 dba for daytime and 55 dba for nighttime; the standards for L 50 are 60 dba for daytime and 50 dba for nighttime. The MPCA defines daytime as 7:00 a.m. to 10:00 p.m. and nighttime from 10:00 p.m. to 7:00 a.m. State noise standards are depicted in Table 2. Highway 100 Reconstruction Project 3 July 2012

6 TABLE 2 MINNESOTA STATE NOISE STANDARDS MPCA State Noise Standards Land Use Code Daytime (7 a.m. 10 p.m.) dba Nighttime (10 p.m. 7:00 a.m.) dba Residential NAC 1 L 10 of 65 L 50 of 60 L 10 of 55 L 50 of 50 Commercial NAC 2 L 10 of 70 L 50 of 65 L 10 of 70 L 50 of 65 Industrial NAC 3 L 10 of 80 L 50 of 75 L 10 of 80 L 50 of 75 The State noise standards apply to the project section of Highway 100 (approximately Stephens Drive to 36 th Street). Exemptions to State noise standards are found in Minnesota Statutes 2000, Section subd. (2a). Minnesota Statutes 2000, Section subd. (2a) identifies the conditions and roadway types that are exempt from the State noise standards. The Federal Highway Administration s (FHWA) Procedures for Abatement of Highway Traffic Noise and Construction Noise is presented in the Code of Federal Regulations, Title 23 Part 772 (23 CFR 772). This regulation establishes the noise abatement criteria (NAC) for various land uses. Noise abatement measures will be considered when the predicted noise levels approach (within 1 dba) or exceed those values shown for the appropriate activity category in Table 3, or when the predicted traffic noise levels substantially exceed the existing noise levels. MnDOT has defined an increase over existing noise levels of 5 dba or greater as a substantial noise level increase. July Highway 100 Reconstruction Project

7 TABLE 3 NOISE ABATEMENT CRITERIA HOURLY A WEIGHTED SOUND LEVEL DECIBELS (DBA) FHWA Noise Abatement Criteria Activity Category Activity Criteria (1,2) L 10 dba Evaluation Location Activity Description A 60 Exterior Lands on which serenity and quiet are of extraordinary significance and serve and important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose. B 70 Exterior Residential C 70 Exterior Active sport areas, amphitheaters, auditoriums, campgrounds, cemeteries, day care centers, hospitals, libraries, medical facilities, parks, picnic areas, places of worship, playgrounds, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, recreation areas, Section 4(f) sites, schools, television studios, trails, and trail crossings D 55 Interior Auditoriums, day care centers, hospitals, libraries, medical facilities, places of worship, public meeting rooms, public or nonprofit institutional structures, radio studios, recording studios, schools, and television studios E(3) 75 Exterior Hotels, motels, offices, restaurants/bars, and other developed lands, properties or activities not included in A D or F F Agriculture, airports, bus yards, emergency services, industrial, logging, maintenance facilities, manufacturing, mining, rail yards, retail facilities, shipyards, utilities (water resources water treatment, electrical), and warehousing G Undeveloped lands that are not permitted 1 L 10 shall be used for impact assessment 2 The L 10 Activity Criteria values are for impact determination only, and are not design standards for noise abatement measures. 3 Includes undeveloped lands permitted for this activity category. Highway 100 Reconstruction Project 5 July 2012

8 Methodology Affected Environment The purpose of this noise analysis is to determine the impacts of the proposed project s trafficgenerated noise levels on noise sensitive receptors (residences, businesses, etc.) in the vicinity of the project. It is also important to note that the project setting includes other noise sources in the area that may have some affect on ambient noise levels. The Highway 100 Reconstruction Project is located in an urban environment in the City of Saint Louis Park, Minnesota. Traffic noise is generated by vehicles traveling on the highway, as well as intersecting and parallel roadways. For the purposes of this traffic noise analysis, 36 th Street is the southern project terminus, and Stephens Drive is the northern project terminus. Noise Monitoring Existing traffic noise levels were measured in the field and then compared against computer predictions to verify the accuracy of the computer model. If the predicted and measured levels are within + or 3 dba of one another, this is an indication that the model is within the accepted level of accuracy. Existing noise levels were monitored at eight sites adjacent to the proposed construction areas and were chosen to represent areas of outdoor human activity (i.e. residential land uses). Noise monitoring locations are described below and depicted on Figures 1 4 in Appendix A. Monitoring site 1 is located along the east side of Highway 100 at 2728 Toledo Avenue (see Figure 2). Monitoring site 2 is located along the east side of Highway 100 at 3033 Toledo Avenue (see Figure 3). Monitoring site 3 is located along the west side of Highway 100 at Webster Park (see Figures 3 and 4). Monitoring site 4 is located along the west side of Highway 100 at the Lutheran Church of the Reformation (see Figure 1). Monitoring site 5 is located along the east side of Highway 100 at 2616 Toledo Avenue (see Figure 2). Monitoring site 6 is located along the west side of Highway 100 at 2800 Utica Avenue (see Figure 2). Monitoring site 7 is located along the east side of Highway 100 at 2939 Toledo Avenue (see Figure 2). Monitoring site 8 is located along the east side of Highway 100 at 3111 Toledo Avenue (see Figure 3). July Highway 100 Reconstruction Project

9 Noise levels were monitored in June 2011 and November Traffic noise measurements were conducted in accordance with FHWA PD Measurement of Highway Related Noise (May 1996). The measured and predicted noise levels for each of the monitoring sites selected along the project corridor are presented in Table 4. Each set of predicted and measured data was found to be within the acceptable + or 3 dba tolerance; therefore the model is considered to be validated. TABLE 4 MODEL VALIDATION RESULTS HOURLY A WEIGHTED SOUND LEVEL DECIBELS (DBA) Existing Monitored Results Existing Modeled Results Difference Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Monitoring Location L10 L50 Monitoring Location L10 L50 L10 L Highway 100 Reconstruction Project 7 July 2012

10 Noise Modeling Traffic noise impacts were assessed by modeling noise levels at receptor sites likely to be affected by construction of the proposed project. Traffic noise levels were modeled at 686 representative receptor locations along the project corridor from Stephens Drive to 36 th Street. A majority of these representative receptor locations represented residential land uses. The locations of the modeled receptor sites are illustrated in Figure 1 through Figure 4 in Appendix A. Land uses (residential, commercial, etc.) are listed with each modeled receptor location in Table 7 and Table 8 in Appendix B. Noise modeling was done using the noise prediction program MINNOISE, a version of the FHWA STAMINA model adapted by Mn/DOT. This model uses traffic volumes, speed, class of vehicle, and the typical characteristics of the roadway being analyzed (e.g. roadway horizontal and vertical alignment). Noise model input files were developed based on the following assumptions: Traffic data input into the MINNOISE noise model was provided by Mn/DOT and included existing (year 2011) and future (year 2030) No Build and Build traffic volumes. Year 2030 was identified as the future year for analysis. The 6:00 a.m. to 7:00 a.m. period, just prior to the start of the morning rush hour, was identified through modeling as the loudest hour of the nighttime period (see Table 5). The 3:00 p.m. to 4:00 p.m. period, just prior to the start of the afternoon rush hour, was identified through modeling as the loudest hour of the daytime period (see Table 5). An acoustically soft surface (alpha=0.5) was assumed between modeled receptor locations and modeled roadways in the noise model input files. TABLE 5 LOUDEST NOISE HOUR MODELING EXERCISE Daytime Nighttime Begin L10 Begin L10 Hour Hour 7:00 AM :00 PM :00 AM :00 PM :00 AM :00 AM :00 AM :00 AM :00 AM :00 AM :00 PM :00 AM :00 PM :00 AM :00 PM :00 AM :00 PM :00 AM :00 PM :00 PM :00 PM 76.1 July Highway 100 Reconstruction Project

11 Daytime Begin L10 Hour 7:00 PM :00 PM :00 PM 72.8 Nighttime Begin Hour L10 Noise Model Results Results of the noise modeling analysis are tabulated in Table 7 (daytime) and Table 8 (nighttime) in Appendix B. The following describes the results of the traffic noise analysis for existing (2011), future (2030) No Build conditions, and future (2030) Build conditions. Existing (2011) daytime modeled noise levels at modeled receptor locations range from 56.5 dba (L 10 ) to 77.6 dba (L 10 ), whereas nighttime noise levels range from 54.4 dba (L 10 ) to 75.9 dba (L 10 ). Modeled noise levels exceed State daytime standards (L 10 ) at 418 of 702 modeled receptor locations with existing (2011) conditions. Modeled noise levels exceed State nighttime standards (L 10 ) at 670 of 702 modeled receptor locations with existing (2011) conditions. Future (2030) No Build daytime modeled noise levels range from 56.9 dba (L 10 ) to 77.8 dba (L 10 ), whereas nighttime modeled noise levels range from 54.8 dba (L 10 ) to 76.1 (L 10 ) dba. Modeled noise levels (daytime and nighttime) for No Build conditions increase by 0.0 dba to 0.8 dba over existing conditions. Modeled noise levels exceed State daytime standards (L 10 ) at 431 of 702 modeled receptor locations with No Build (2030) conditions. Modeled noise levels exceed State nighttime standards (L 10 ) at 674 of 702 modeled receptor locations with No Build (2030) conditions. Daytime modeled noise levels range from 56.8 dba (L 10 ) to 78.2 dba (L 10 ) with future (2030) Build conditions. Nighttime modeled noise levels range from 54.8 dba (L 10 ) to 76.4 dba (L 10 ) with future (2030) Build conditions. Modeled noise levels (daytime and nighttime) vary 3.7 dba to 6.4 dba from existing (2011) conditions. Modeled noise levels exceed State daytime standards (L 10 ) at 432 of 702 modeled receptor locations with Build (2030) conditions. Modeled noise levels exceed State nighttime standards (L 10 ) at 679 of 702 modeled receptor locations with Build (2030) conditions. Traffic Noise Abatement Analysis Because State noise standards are exceeded at modeled receptor locations along Highway 100 with the Project, noise abatement in the form of a noise barrier must be considered. However, any of the noise abatement measures listed below shall be considered if a noise barrier is determined not feasible or not reasonable: Highway 100 Reconstruction Project 9 July 2012

12 Construction of noise barriers including acquisition of property rights, either within or outside the highway right of way. Landscaping or privacy fencing is not a viable noise abatement measure. Traffic management measures including, but not limited to, traffic control devices and signing for prohibition of certain vehicle types, time use restrictions for certain vehicle types, modified speed limits, and exclusive lane designations. (This option may not be practical for most state interstate highways.) Alteration of horizontal and vertical alignments (usually considered in the evaluation and comparison of noise impacts of various project build alternatives). Acquisition of real property or interests therein (predominately unimproved property) to serve as a buffer zone to preempt development which would be adversely impacted by traffic noise. This measure may be included in Type I projects only. Noise insulation of Activity Category D land use facilities listed in Table 3. Postinstallation maintenance and operational costs for noise insulation are not eligible for Federal aid funding. Noise Barrier Evaluation Noise barrier construction decisions are based on a study of feasibility and reasonableness. Feasibility is determined by physical and/or engineering constraints (i.e. whether a noise barrier could feasibly be constructed on the site) and by acoustic ability (at least one impacted receptor per proposed barrier must receive the minimum reduction of 5 dba to achieve acoustic feasibility). There are three reasonableness factors that must be met for a noise abatement measure to be considered reasonable. 1. A noise reduction design goal of at least 7 dba must be achieved at a minimum of one benefited receptor for each proposed noise abatement measure to be considered reasonable. 2. A cost effectiveness threshold of $43,500 per individual benefited receptor has been established, based on an estimated construction cost of $20/ft 2 for noise walls (additional costs of some items such as guard rail, rub rail, purchased right of way, etc.., shall be added to the baseline unit costs cited above for the purpose of cost estimation). 3. The viewpoints of the property owners and residents of all benefited receptors shall be solicited and considered in reaching a decision on the abatement measures to be provided. Please see Section of the Mn/DOT Noise Policy (effective date: June 1, 2011) for a detailed explanation of the voting system. A simple majority (greater than 50%) of all possible voting points (not just the ones that reply) for each potential noise abatement measure must vote down the abatement measure to removed it from further consideration. July Highway 100 Reconstruction Project

13 There are several steps to assessing the cost effectiveness of noise barriers. First, the costeffective noise barrier height is determined for each segment of the project area. For this study, three heights of potential noise barriers were analyzed: 20 feet (Mn/DOT s maximum height), 15 feet (if necessary), and 10 feet (if necessary). If a 20 foot tall noise barrier meets the reasonableness criteria and is feasible, it would be proposed for construction. If the 20 foot tall barrier does not meet the criteria, a 15 foot high barrier is evaluated. Likewise, if a 15 foot tall barrier does not meet the criteria, a 10 foot high barrier is studied. If a 10 foot tall noise barrier meets the reasonableness criteria and is feasible, it would then be proposed for construction. All barriers evaluated must meet Mn/DOT s 7 dba noise reduction design goal. If a barrier is unable to achieve the 7 dba noise reduction design goal, further evaluation of shorter barrier heights will not completed. Noise barriers were evaluated at all modeled residential receptor locations where State daytime and/or nighttime noise standards with future (2030) Build conditions are exceeded. The locations with modeled noise barriers are shown in Figures 1 through 4 in Appendix A. Noise barrier cost effectiveness results are tabulated at the end of this report in Appendix C. The discussion of noise barrier modeling results presented below includes only daytime results. For reference, nighttime noise barrier cost effectiveness results are also tabulated and presented at the end of this report with the daytime noise barrier cost effectiveness results. Results of daytime noise barrier cost effectiveness are consistent with noise barrier costeffectiveness results for nighttime conditions. Highway 100 Reconstruction Project 11 July 2012

14 Area A (west of Highway 100 between Stephens Drive and W 26 th Street) Land uses west of Highway 100 between Stephens Drive and W 26 th Street consist of 3 commercial businesses, several apartment buildings, and the Lutheran Church of the Reformation. A frontage road parallels the highway right of way and is located between the highway and the land uses in Area A. Noise levels were modeled at 97 receptor locations in Area A. Modeled noise levels exceed State daytime standards at 88 of the 97 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 97 of 97 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier A1 Receptor 1 (see Figure 1) An approximately 531 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 south from Stephens Drive. The approximately 531 foot long barrier provides a reduction of 8.0 dba. The cost effectiveness of the barrier is $212,400 per benefited receptor. The approximately 531 foot long, 20 foot high modeled Barrier A1 does not meet Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Therefore, an approximately 531 foot long, 15 foot high noise barrier was modeled along the west side of Highway 100 south from Stephens Drive. The approximately 531 foot long barrier provides a reduction of 7.4 dba. The cost effectiveness of the barrier is $159,300 per benefited receptor. The approximately 531 foot long, 15 foot high modeled Barrier A1 does not meet Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Therefore, an approximately 531 foot long, 10 foot high noise barrier was modeled along the west side of Highway 100 south from Stephens Drive. The approximately 531 foot long barrier provides a reduction of 5.6 dba. The cost effectiveness of the barrier is $106,200 per benefited receptor. The approximately 531 foot long, 10 foot high modeled Barrier A1 does not meet Mn/DOT s 7 dba noise reduction design goal nor Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. July Highway 100 Reconstruction Project

15 Noise Barrier A2 Receptors 2 through 49 (see Figure 1) An approximately 908 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting near the Park Ridge Apartments and heading south to an existing pedestrian bridge near 26 th Street NW. The approximately 908 foot long barrier provides a reduction that varies from 2.2 dba to 14.6 dba. The cost effectiveness of the barrier is $4,540 per benefited receptor. The approximately 908 foot long, 20 foot high modeled Barrier A2 meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area B (west of Highway 100 between W 26 th Street and Minnetonka Boulevard) Land uses west of Highway 100 between W 26 th Street and Minnetonka Boulevard consist of 77 single family homes and one commercial business (Holiday Station Store). A frontage road parallels the highway right of way and is located between the highway and the land uses in Area B. Noise levels were modeled at 78 receptor locations in Area B. Modeled noise levels exceed State daytime standards at 78 of the 78 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 78 of 78 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier B1 Receptors 50 through 62 (see Figure 2) An approximately 485 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting at the existing pedestrian bridge near W 26 th Street and heading south along the proposed slip ramp. The approximately 485 foot long barrier provides a reduction that varies from 6.2 dba to 9.5 dba. The cost effectiveness of the barrier is $14,923 per benefited receptor. The approximately 485 foot long, 20 foot high modeled Barrier B1 meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Noise Barrier B2 Receptors 63 through 127 (see Figure 2) An approximately 2,143 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting near 27 ½ St W and heading south to near Minnetonka Boulevard. The approximately 2,143 foot long barrier provides a reduction that varies from 1.3 dba to 12.1 dba. The cost effectiveness of the barrier is $13,394 per benefited receptor. Highway 100 Reconstruction Project 13 July 2012

16 The approximately 2,143 foot long, 20 foot high modeled Barrier B2 meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area C (west of Highway 100 between Minnetonka Boulevard and Highway 7) Land uses west of Highway 100 between Minnetonka Boulevard and Highway 7 consist of apartments, single family homes, several commercial businesses and a park. Noise levels were modeled at 59 receptor locations in Area C. Modeled noise levels exceed State daytime standards at 48 of the 59 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 55 of 59 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier C Receptors 128 through 186 (see Figure 3) An approximately 2,099 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting approximately 650 feet south of Minnetonka Boulevard and heading south along Highway 100 eventually heading west along the proposed off ramp from Highway 100 to westbound Highway 7. The approximately 2,099 foot long barrier provides a reduction that varies from 0.1 dba to 10.9 dba. The cost effectiveness of the barrier is $33,584 per benefited receptor. The approximately 2,099 foot long, 20 foot high modeled Barrier C meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area D (west of Highway 100 between Highway 7 and W 36 th Street) Land uses west of Highway 100 between Highway 7 and W 36 th Street consist of apartments and two commercial businesses. Noise levels were modeled at 302 receptor locations in Area D. Modeled noise levels exceed State daytime standards at 163 of the 302 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 302 of 302 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier D1 Receptors 187 through 221 (see Figure 4) An approximately 626 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting near Highway 7 and heading south along the southbound Highway 100 on ramp for approximately 626 feet to the trail/rr tracks. The approximately 626 foot long barrier provides a reduction that varies from 0.0 dba to 4.8 dba. July Highway 100 Reconstruction Project

17 The approximately 626 foot long, 20 foot high modeled Barrier D1 does not meet Mn/DOT s 7 dba noise reduction design goal and is not proposed as part of the Highway 100 Reconstruction Project. Noise Barrier D2 Receptors 222 through 261 (see Figure 4) An approximately 700 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting near the trail/rr tracks and heading south to approximately 35 ½ Street W. The approximately 700 foot long barrier provides a reduction that varies from 0.0 dba to 5.5 dba. The cost effectiveness of the barrier is $70,000 per benefited receptor. The approximately 700 foot long, 20 foot high modeled Barrier D2 does not meet Mn/DOT s 7 dba noise reduction design goal nor Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Noise Barrier D3 Receptors 262 through 263 (see Figure 4) An approximately 296 foot long, 20 foot high noise barrier was modeled along the west side of Highway 100 starting near 35 ½ Street W and heading south to approximately 36 th Street W. The approximately 296 foot long barrier provides a reduction that varies from 2.4 dba to 5.6 dba. The cost effectiveness of the barrier is $118,400 per benefited receptor. The approximately 296 foot long, 20 foot high modeled Barrier D3 does not meet Mn/DOT s 7 dba noise reduction design goal nor Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Area E (east of Highway 100 between Stephens Drive and 26th Street) Land uses east of Highway 100 between Stephens Drive and 26 th Street consist of Benilde St. Margaret s School and Beth El Synagogue. Noise levels were modeled at 11 receptor locations in Area E. Modeled noise levels exceed State daytime standards at 11 of the 11 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 11 of 11 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier E Receptors 264 through 274 (see Figure 1) An approximately 1,379 foot long, 20 foot high noise barrier was modeled along the east side of Highway 100 starting near Stephens Drive and heading south along Highway 100 to approximately W 26 th Street. The approximately 1,379 foot long, 20 foot high, barrier provides Highway 100 Reconstruction Project 15 July 2012

18 a reduction that varies from 3.1 dba to 13.7 dba. The cost effectiveness of the barrier is $55,160 per benefited receptor. The approximately 1,379 foot long, 20 foot high, modeled Barrier E does not meet Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Therefore, an approximately 1,379 foot long, 15 foot high, barrier was modeled along the east side of Highway 100 starting near Stephens Drive and heading south along Highway 100 to approximately W 26 th Street. The approximately 1,379 foot long, 15 foot high, barrier provides a reduction that varies from 2.9 dba to 11.1 dba. The cost effectiveness of the barrier is $41,370 per benefited receptor. The approximately 1,379 foot long, 15 foot high modeled Barrier E meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area F (east of Highway 100 between W 26 th Street and Minnetonka Boulevard) Land uses east of Highway 100 between W 26 th Street and Minnetonka Boulevard consist of single family homes and St. Georges Church. Noise levels were modeled at 77 receptor locations in Area F. Modeled noise levels exceed State daytime standards at 77 of the 77 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 77 of 77 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier F Receptors 275 through 351 (see Figure 2) An approximately 2,509 foot long, 20 foot high noise barrier was modeled along the east side of Highway 100 starting near the pedestrian bridge at W 26 th Street and heading south along Highway 100 to approximately Minnetonka Boulevard. The approximately 2,509 foot long barrier provides a reduction that varies from 0.9 dba to 12.2 dba. The cost effectiveness of the barrier is $14,979 per benefited receptor. The approximately 2,509 foot long, 20 foot high modeled Barrier F meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area G (east of Highway 100 between Minnetonka Boulevard and County Road 25) Land uses east of Highway 100 between Minnetonka Boulevard and County Road 25 consist of single family homes, an apartment building and a recreation trail. July Highway 100 Reconstruction Project

19 Noise levels were modeled at 70 receptor locations in Area G. Modeled noise levels exceed State daytime standards at 47 of the 70 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 63 of 70 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier G Receptors 352 through 389 (see Figure 3) An approximately 1,495 foot long, 20 foot high noise barrier was modeled along the east side of Highway 100 from approximately Minnetonka Boulevard to County Road 25. The approximately 1,495 foot long barrier provides a reduction that varies from 0.0 dba to 16.9 dba. The cost effectiveness of the barrier is $35,176 per benefited receptor. The approximately 1,495 foot long, 20 foot high modeled Barrier G meets Mn/DOT s minimum $43,500 cost effectiveness criteria and is proposed as part of the Highway 100 Reconstruction Project. Area H (east of Highway 100 between County Road 25 and the Railroad Tracks) Land uses east of Highway 100 between Country Road 25 and the railroad tracks consist of Bee Hive Park, Nordic Ware, and several other commercial businesses. The traffic noise impacts in this area occur at Bee Hive Park. Noise levels were modeled at 8 receptor locations in Area H. Modeled noise levels exceed State daytime standards at 5 of the 8 receptor locations with future (2030) Daytime Build conditions and State nighttime standards at 3 of 8 receptor locations with future (2030) Nighttime Build conditions. Noise Barrier H Receptors 391 through 395 (see Figures 3 and 4) An approximately 849 foot long, 20 foot high noise barrier was modeled along the east side of Highway 100 from approximately County Road 25 heading 849 feet south to the railroad tracks. The approximately 849 foot long barrier provides a reduction that varies from 4.9 dba to 8.8 dba. The cost effectiveness of the barrier is $84,900 per benefited receptor. The approximately 849 foot long, 20 foot high modeled Barrier H does not meet Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. Therefore, an approximately 849 foot long, 15 foot high noise barrier was modeled along the east side of Highway 100 from approximately County Road 25 heading 849 feet south to the railroad tracks. The approximately 849 foot long, 15 foot high, barrier provides a reduction that Highway 100 Reconstruction Project 17 July 2012

20 varies from 3.5 dba to 5.8 dba. The cost effectiveness of the barrier is $127,350 per benefited receptor. The approximately 849 foot long, 15 foot high modeled Barrier H does not meet Mn/DOT s 7 dba noise reduction design goal nor Mn/DOT s minimum $43,500 cost effectiveness criteria and is not proposed as part of the Highway 100 Reconstruction Project. July Highway 100 Reconstruction Project

21 Construction Noise The construction of the proposed project will result in temporary noise and vibration increases within the project area. The noise and vibration would be generated primarily from heavy equipment used in hauling materials and building the roadway improvements. Sensitive areas located close to the construction area may temporarily experience increased noise and vibration levels. The following have been identified as being potential construction noise and vibration sensitive sites that exist along the project corridor: residences and several churches. MnDOT incorporates a number of provisions that are to be used on MnDOT projects to reduce the impacts of construction noise. This includes but is not limited to work hours, installation of mufflers on equipment, and requirements to receive the appropriate operation approvals from the appropriate local officials. Conclusions In general, construction of the Highway 100 Reconstruction project will result in increases in traffic noise levels compared to existing conditions. In some locations where the new alignment results in traffic being shifted away from modeled receiver locations, the increase is predicted to be smaller compared to other locations along the project corridor, and may in fact result in a decrease in future noise levels. Changes in daytime traffic noise levels (L 10 ) are projected to range from 3.7 dba to +6.4 dba from existing to future (2030) Build conditions. Cost effectiveness of noise barriers was calculated, Table 6 lists the barriers that were found to be feasible and reasonable. All of these barriers are proposed as part of the project. Final mitigation decisions will be subject to input from affected property owners and final design considerations. TABLE 6 CONSIDERED NOISE BARRIERS Noise Barrier Location Length Height Barrier A1 Not proposed Barrier A2 Proposed West of Highway 100 between Park Ridge Apartments and an existing pedestrian bridge near 26 th Street NW (Figure 1) Barrier B1 Proposed West of Highway 100 between existing pedestrian bridge near W 26 th Street south along the proposed slip ramp (Figure 2) Barrier B2 Propsed West of Highway 100 between 27 ½ Street W and Minnetonka Boulevard (Figure 2) 2, Barrier C Proposed West of Highway 100 between Minnetonka Boulevard and the proposed off ramp to WB Highway 7 (Figure 3) 2, Barrier D1 Not proposed Barrier D2 Not proposed Barrier D3 Not proposed Barrier E Proposed East of Highway 100 between Stephens Drive and W 26 th Street 1, Highway 100 Reconstruction Project 19 July 2012

22 Noise Barrier Location Length Height (Figure 1) Barrier F Proposed East of Highway 100 between the existing pedestrian bridge at W 26 th Street and Minnetonka Boulevard (Figure 2) 2, Barrier G Proposed East of Highway 100 between Minnetonka Boulevard and 1, County Road 25 Barrier H Not proposed July Highway 100 Reconstruction Project