Memorandum 1.0 Highway Traffic Noise

Transcription

1 Memorandum Date: September 18, 2009 To: Chris Hiniker, SEH From: Stephen B. Platisha, P.E. Re: Updated CSAH 14 Noise Analysis The purpose of this memorandum is to provide the results of the revised traffic noise analysis for the CSAH 14 reconstruction project. The project area is located in Coon Rapids, Minnesota. The project will expand the existing 2-lane roadway to a 4-lane roadway from east of Trunk Highway 10 to east of Hanson Boulevard. This analysis was conducted to reflect the updated project design, updated traffic predictions, and the change in the applicability of the State noise rules due to the County ownership of the road. 1.0 Highway Traffic Noise An analysis of the existing, No-Build, and Build traffic noise levels was conducted using the Mn/DOT augmented Federal noise program, MINNOISE computer model, and traffic predictions prepared as part of this noise assessment. Modeled results were compared to Federal noise abatement criteria to determine the potential effects of the project. Furthermore, the project was using Federal noise abatement criteria contained in 23 CFR Part 772. The rule provides procedures for noise studies and noise abatement measures to help protect the public health and welfare; it describes noise abatement criteria, and establishes requirements for information to be given to local officials for use in planning and design. In addition to the Federal noise abatement criteria, the State of Minnesota has established a set of noise standards that are more restrictive than the Federal criteria. However, as stipulated in Minnesota Statute , Subd. 2a, CSAH 14 (County Highway 14) is exempt from the state noise standards. The statute states: (2a) No standards adopted by any state agency for limiting levels of noise in terms of sound pressure which may occur in the outdoor atmosphere shall apply to (1) segments of trunk highways constructed with federal interstate substitution money, provided that all reasonably available mitigation measures are employed to abate noise, (2) an existing or newly constructed segment of a highway,

2 provided that all reasonably available noise mitigation measures, as approved by the commissioners of the department of transportation and pollution control agency, are employed to abate noise, (3) except for the cities of Minneapolis and St. Paul, an existing or newly constructed segment of a road, street, or highway under the jurisdiction of a road authority of a town, statutory or home rule charter city, or county, except for roadways for which full access has been acquired As a result, this noise analysis focuses solely on the Federal noise abatement criteria. 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 represent the logarithmic measure of sound energy relative to a reference energy level. For highway traffic noise, an adjustment, or weighting, of the high- and lowpitched sounds is made to approximate the way that an average person hears sounds. The adjusted sound levels are stated in units of "A-weighted decibels" (dba). A sound increase of three dba is barely perceptible to the human ear, a five dba increase is clearly noticeable, and a 10 dba increase is heard as twice as loud. For example, if the sound energy is doubled (e.g., the amount of traffic doubles), there is a 3 dba increase in noise, which is just barely noticeable to most people. On the other hand, if traffic increases to where there is 10 times the sound energy level over a reference level, then there is a 10 dba increase and it is heard as twice as loud. The following table provides a rough comparison of the noise levels of some common noise sources. Sound Pressure Level Noise Source (dba) 140 Jet Engine (at 25 meters) 130 Jet Aircraft (at 100 meters) 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, Page 2

3 Along with the volume of traffic and other factors (i.e., 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 levels decrease as distance from a source increases. The common rule of thumb used to describe sound decreases due to distance states that, beyond approximately 50 feet, each time the distance between a line source (such as a road) and a receptor is doubled, sound levels decrease by 3 decibels over hard ground, such as pavement or water, and by 4.5 decibels over vegetated areas. Traffic noise impacts are evaluated by measuring and/or modeling the traffic noise levels that are exceeded 10 percent of the time during the noisiest hour of the day (typically the heaviest free flow traffic condition). This number is identified as the L 10 level. Federal noise abatement criteria have been established for five land use categories as shown in Table 1. Locations where noise levels are approaching (defined as being within 1-decibel of the criteria threshold, e.g. 69 dba in a residential area) or exceeding the criteria level must be evaluated for noise abatement reasonableness. Category B was used in this analysis. Table 1 Federal Noise Abatement Criteria Category L 10 dba Land Use A 60 Special areas requiring serenity B 70 Residential and recreational areas (playgrounds, active sports areas, parks) C 75 Commercial and industrial areas (developments not included in Categories A or B above). D NA Undeveloped areas E 55 * Residential, schools, churches, libraries, and hospitals * Applies to interior noise levels. All other land uses are exterior levels. In addition, FHWA also defines noise impacts in terms of a substantial increase in the future noise levels over the existing noise levels. Mn/DOT considers an increase of 5 dba or greater to be a substantial noise level increase. 2.0 Modeled Impacts Traffic noise impacts were assessed by modeling noise levels at residential receptor sites along the corridor likely to be most affected by the proposed project. In determining and abating traffic noise impacts, primary consideration is given to exterior areas where frequent human use occurs and a lowered noise level would be of benefit. Noise receptor locations were chosen to represent portions of residential properties facing the project corridor. Noise modeling was conducted using the MINNOISE Noise Prediction Program. This model uses vehicle numbers (peak free-flow conditions), speed (posted), class of vehicle Page 3

4 (cars and trucks), and the typical characteristics of the roadway being analyzed (horizontal and vertical profile). The specific model inputs are provided in Attachment A. Extensive noise monitoring studies were conducted along CSAH 14 and TH 65 in 2002 and 2004 documenting existing noise levels for the 2005 Environmental Assessment for the reconstruction of these two roadways. Monitored levels were consistent with modeled levels in the project area MINNOISE Model Results The noise analysis was conducted for current conditions, the year 2030 no-build, and the year 2030 build. Model results are provided in Attachment B. Figures A D in Attachment C show the modeled receptor locations. The model results indicate no receptors experiencing a substantial increase (>5 db) in noise levels when comparing existing and Year 2030 build conditions. However there are receptors along the project corridor with noise levels at or above 69 db. Given these exceedances, the next step in the noise analysis process is to consider potential mitigation measures to address the identified noise impacts along the corridor. 3.0 Mitigation Assessment The FHWA guidelines do state that noise abatement measures are to be considered for the proposed project as impacts have been identified as approaching and/or exceeding the NAC. Such measures included traffic control devices, signing for prohibition of certain vehicle types, time-use restrictions for certain vehicle types, modified speed limits, exclusive land use designations, and other methods as listed in 23 CFR c. These additional abatement measures are summarized below. Traffic Management Measures: This would include a partial or total ban on trucks, time-use restrictions for certain vehicle types, and reduced speed limits. Although these measures would reduce traffic noise levels somewhat, to limit the vehicle types, time of use, and speeds on the new roadway would not be consistent with the function of CSAH 14. Therefore, traffic management measures are not considered reasonable or feasible. Horizontal and Vertical Alignment: The alignment of the existing roadway is restricted to its current location because of constraints caused by development, surrounding topography, natural resources and connections to existing roadways. Further substantial shifts in the proposed project alignment to reduce noise at residential receptors near CSAH 14 are not feasible because of other resulting impacts, including residential and commercial relocations and increased noise at other residential receptors. Landscaping/Natural Noise Screening: The use of vegetation as a noise screen can be effective only if at least 75 to 100 feet of dense, evergreen vegetation (evergreen vegetation maintains its foliage year around) is provided between the source and receptor. Along the CSAH 14 corridor, there is not enough right-of- Page 4

5 way between the roadway and existing receptors that exceed the noise standards to provide an adequate vegetative noise screen. Therefore, vegetation as a noise mitigation measure is not a reasonable and feasible alternative. Acquisition of Property: Because much of the project corridor is already developed, the ensuing right-of-way and community impacts make this an unreasonable and infeasible option. Acoustical Insulation of Houses: The FHWA guidelines and Mn/DOT policy recommend that only public buildings such as schools and hospitals be considered for acoustical insulation. Construction of Noise Barriers: These may include various types of noise barriers such as wood and concrete and may include landscaping for aesthetic purposes whether within or outside the highway right-of-way. Of these mitigation techniques only construction of noise barriers has the potential to be both feasible and reasonable for implementation in the project corridor. 3.1 Noise Barrier Analysis Noise barriers were considered at residential locations where modeled future (2030) noise levels approach or exceed the Federal criteria (69 dba or greater). The analysis did not identify any locations that are expected to receive a 5 dba or greater increase in design year noise levels when compared to existing noise levels.. 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). Reasonableness is a more subjective measure and is based on a number of factors. For a noise barrier to be considered acoustically effective, it must achieve a noise reduction of 5 dba or more. To be considered cost-effective the cost per dba of reduction per residence should be equal to or less than $3,250. Cost-effectiveness of the barrier is calculated by dividing the cost of the noise barrier ($15 per square foot for noise walls) by the product of the average decibel reduction and the total number of residences that receive at least a 5 dba reduction in noise levels. The result of this calculation is a cost per decibel per residence. This overall approach is outlined in Mn/DOT Noise Policy for Type I and Type II Federal-Aid Projects as per 23 CFR 772. If noise mitigation is found to be cost-effective, additional reasonableness factors, such as the desires of affected property owners, are considered. Given the results of the noise impact analysis, the feasibility of noise walls was assessed at six areas along the corridor where Federal noise criteria were exceeded. The areas considered for mitigation are as follows: Area A: West of Shenandoah Boulevard, North Side Page 5

6 Area B: West of Shenandoah Boulevard, South Side Area C: West of Hanson Boulevard, North Side Area D: West of Hanson Boulevard, South Side Area E: East of Hanson Boulevard, North Side Area F: East of Hanson Boulevard, South Side The locations of the potential walls analyzed are shown in Figures A D in Attachment C. Initially, 10-foot high, 15-foot high, and 20-foot high walls were considered for each of the mitigation areas. Based on this analysis, the following areas were found to potentially meet the cost reasonableness criteria: Area A: West of Shenandoah Boulevard, North Side Area B: West of Shenandoah Boulevard, South Side Area D: West of Hanson Boulevard, South Side Area E: East of Hanson Boulevard, North Side The lowest cost reasonableness value for area C was $6,330/dBA/residence (with a 15- foot barrier), above the Mn/DOT $3,250/dBA/residence cost reasonableness threshold, so this area was eliminated from further consideration for noise barrier mitigation. The lowest cost reasonableness value for area F was $3,914/dBA/residence (with a 15-foot barrier), above the Mn/DOT $3,250/dBA/residence cost reasonableness threshold, so this area was eliminated from further consideration for noise barrier mitigation. Attachment D contains the detailed cost-reasonableness analysis for each potential barrier location. Wall heights and locations were optimized for Areas A, B, D, and E to reduce construction costs, while achieving significant noise level reductions and still meeting the cost reasonableness criteria of $3,250/dBA/residence. The results of the cost reasonableness assessments are summarized as follows: Area A: 14 West of Shenandoah Boulevard, North Side The modeled receptors in this area represent 33 residences north of CSAH 14 and west of Shenandoah Boulevard. The optimized barrier includes a 596-foot long, 9- foot high barrier section east of the emergency access road, and a 510-foot long, 9- foot high barrier section west of the emergency access road. The cost per decibel per residence for this noise barrier is $1,665, which meets Mn/DOT s criteria of equal to or less than $3,250. Area B: West of Shenandoah Boulevard, South Side The modeled receptors represent 27 residences south of CSAH 14 and west of Shenandoah Boulevard. The optimized barrier for this location is 2083 feet long Page 6

7 with the westernmost 90 feet being 12-feet high, the next 280 feet being 13 feet high, and the rest of the barrier being 11-feet high. The cost per decibel per residence for this noise barrier is $2,947, which meets Mn/DOT s criteria of equal to or less than $3,250. This cost includes an additional $40,000 for right-of-way acquisition. Area D: West of Hanson Boulevard, South Side These receptors represent 20 residences in the neighborhood to the south of CSAH 14 and west of Hanson Boulevard. The optimized barrier for this location is 956 feet long and 13 feet high. The cost per decibel per residence for this noise barrier is $3,144, which meets Mn/DOT s criteria of equal to or less than $3,250. Area E: East of Hanson Boulevard, North Side These receptors represent the multi-familty building and additional residences east of Hanson Boulevard and north of CSAH 14. The optimized barrier for this location is 607 feet long and 11 feet high. The cost per decibel per residence for this noise barrier is $2,326, which meets Mn/DOT s criteria of equal to or less than $3,250. The detailed results of the cost reasonableness assessments are provided in Attachment D. 4.0 Summary and Next Steps Table 2 summarizes the cost reasonableness evaluation for noise wall mitigation along the CSAH 14 project corridor. Table 2 Noise Wall Cost Reasonableness Assessment Summary Area Description Height (ft.) Length (ft.) Area (ft. 2 ) Wall Cost ($) Cost/dBA ($) A West of Shenandoah Boulevard North 9 1,106 9, ,310 1,665 Side 9 high and 510 long west of development entrance 9 high and 595 feet long east of development entrance B West of Shenandoah Boulevard South , ,445 * 2,947 Side Westernmost 90 is 12 high, the next 280 feet is 13 high, with the rest being 11 high C West of Hanson Boulevard North Side , ,275 6,330 2 sections East and West of Ibis Street D West of Hanson Boulevard - South Side , ,420 3,144 E East of Hanson Boulevard North Side , ,115 ** 2,326 F East of Hanson Boulevard South Side , ,875 3,914 * This cost includes $40,000 for right-of-way acquisition. ** This cost includes $5,000 for an easement. Page 7

8 As shown in Table 2, noise walls in mitigation areas A, B, D, and E meet Mn/DOT s cost reasonableness criteria of $3,250/decibel/residence. In accordance with FHWA procedures, after identifying the potential noise wall segments that met the cost criteria, the next step in the mitigation process is to solicit input from those residences directly affected by the potential noise walls. 5.0 Prevention of Future Noise Impacts FHWA encourages state and local governments to practice compatible land use planning and control in the vicinity of roadways. Local governments should use their power to regulate land development in such a way that noise-sensitive land uses are either prohibited from being located adjacent to the identified roadway, or that the developments are planned, designed, and constructed in such a way that noise impacts are minimized. Local government officials need to know what noise levels to expect and what techniques they can use to prevent future impacts. Such information should also be made available for disclosure in real estate transactions. To prevent future traffic noise impacts on currently undeveloped lands, 23 CFR requires coordination with local government officials, within whose jurisdiction the roadway project is located, regarding the potential noise impacts of a proposed Type I project. The appropriate local planning official shall be informed, in writing, of the following: 1. The best estimation of future noise levels (for various distances from the roadway improvement) for both developed and undeveloped lands or properties in the immediate vicinity of the project; 2. Information that may be useful to local communities to protect future land development from becoming incompatible with anticipated roadway noise levels; and 3. Eligibility for Federal-aid participation for Type II projects as described in 23 CFR b. It is recommended that a copy of this memorandum be kept on file with the City s planning commission to be referenced as adjacent lands to Anoka CSAH 14 are developed or potentially developed. Page 8

9 Attachment A MINNOISE Model Inputs

10 Date: January 6, 2008 To: File From Steve Platisha, SBP Associates, Inc. Re; CSAH 14 Model Inputs Memorandum The purpose of this memorandum is to provide detail on traffic and other inputs to the Minnoise model used to assess impacts of the CSAH 14 corridor improvement project. Minnoise Model The Minnoise model is a modified (modified by the Minnesota Department of Transportation) version of the Federal Highway Administration s Optima/Stamina model that is used to predict noise levels from highway projects and to assist with the development of noise barriers. Model Assumptions Noise level predictions were based on the following data and assumptions: The noise analysis was completed for the peak afternoon rush hour. Traffic data for CSAH build and no-build for the study was generated by WSB and Associates. Existing traffic volumes and volumes on Shenandoah were based on the WSB report, on the original noise study and on published data. The analysis assumed acoustically soft ground cover between the roadway and all receiver locations (alpha = 0.5).

11 Traffic and roadway assumptions used in the model are as follows: CSAH 14 Noise Modeling Daytime Traffic Inputs * Roadway Cars Medium Trucks Heavy Trucks Speed (mph) CSAH 14 West 2038/1645/ /63/57 114/92/84 55 of Shenandoah CSAH 14 Shenandoah to Hanson CSAH 14 East Of Hanson Shenandoah North of CSAH 14 Shenandoah South of CSAH 14 Hanson North of CSAH 14 Hanson South of CSAH 14 * build/no-build/existing 1938/1600/ /61/56 108/89/ /1554/ /60/55 104/87/ /251/228 9/9/8 5/5/ /173/157 6/6/5 3/3/ /2038/ /71/65 41/41/ /1811/ /63/57 46/46/33 45

12 Attachment B Noise Impact Modeling Results

13 CSAH 14 Reconstruction Project Peak- Hour Modeled Project Impacts Areas A and B * Receptor Existing Noise Levels (L 10-dBA) No-Build Noise Levels (L 10-dBA) No-Build Increase Over Existing Noise Levels (L 10-dBA) Post-Development Noise Levels (L 10-dBA) Post-Development Increase Over Existing Noise Levels (L 10-dBA) A A A A A A A A A A A A A A A A A A A A A A A B B B B B B B B B B B B B B B B B B B B B B B B B B B * Shaded values approach or exceed Federal noise abatement criteria.

14 CSAH 14 Reconstruction Project Peak- Hour Modeled Project Impacts Areas C, D, E, and F Receptor Existing Noise Levels (L 10-dBA) No-Build Noise Levels (L 10-dBA) No-Build Increase Over Existing Noise Levels (L 10-dBA) Post-Development Noise Levels (L 10-dBA) Post-Development Increase Over Existing Noise Levels (L 10-dBA) C C C C C C C C C C C C C C C C C D D D D D D D D D D D D D D D D D D D D E E E E E F F F F F F F * Shaded values approach or exceed Federal noise abatement criteria.

15 Attachment C Noise Receptor and Barrier Locations

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20 Attachment D Noise Wall Cost Reasonableness Analysis

21 Area A - North Side - West of Shenandoah 9' Noise Wall - Cost Reasonableness Assessment Receptor No wall 9' wall Noise Reduction Residences Total Reduction A < A < A < A < A A A A A < A < A A A A A < A < A < A < A < A < A < A A < DECIBLE REDUCTION ' WALL LENGTH (FT.) 596 9' WALL LENGTH (FT.) 510 WALL COST ($) COST/Dba ($)

22 Area A - North Side - West of Shenandoah 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction A < A < A < A < A A A A A < A < A A A A A < A A < A < A < A < A < A A < DECIBLE REDUCTION ' WALL LENGTH (FT.) ' WALL LENGTH (FT.) 510 WALL COST ($) COST/Dba ($)

23 Area A - North Side - West of Shenandoah 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction A < A < A < A < A A A A A < A < A A A A A < A A < A < A A A A A < DECIBLE REDUCTION ' WALL LENGTH (FT.) ' WALL HEIGHT (FT.) 510 WALL COST ($) COST/Dba ($)

24 Area A - North Side - West of Shenandoah 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction A < A < A < A < A A A A A < A < A A A A A < A A A < A A A A A < DECIBLE REDUCTION ' WALL LENGTH (FT.) ' WALL LENGTH (FT.) 510 WALL COST ($) COST/Dba ($)

25 Area B - South Side - West of Shenandoah 11' - 13' Noise Wall - Cost Reasonableness Assessment Receptor No wall 11' to 13' wall Noise Reduction Residences Total Reduction B < B B B B B B B B B B B B B < B < B B B < B B < B B < B B < B < B B DECIBLE REDUCTION ' WALL LENGTH (FT.) ' WALL LENGTH (FT.) 90 11' WALL LENGTH (FT.) 1713 Right-of-Way Cost ($) WALL COST ($) COST/Dba ($)

26 Area B - South Side - West of Shenandoah 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction B < B < B < B B B B < B B B B B < B B < B < B < B < B < B B < B < B < B < B < B < B B DECIBLE REDUCTION 80.5 WALL LENGTH (FT.) 2084 WALL HEIGHT (FT.) 10 Right-of-Way Cost ($) WALL COST ($) COST/Dba ($)

27 Area B - South Side - West of Shenandoah 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction B < B B B B B B B B B B B B B < B < B B B B B B B B B < B < B B DECIBLE REDUCTION WALL LENGTH (FT.) 2084 WALL HEIGHT (FT.) 15 Right-of-Way Cost ($) WALL COST ($) COST/Dba ($)

28 Area B - South Side - West of Shenandoah 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction B < B B B B B B B B B B B B B B B B B B B B B B B B < B B DECIBLE REDUCTION WALL LENGTH (FT.) 2084 WALL HEIGHT (FT.) 20 Right-of-Way Cost ($) WALL COST ($) COST/Dba ($)

29 Area C - North Side - West of Hanson - 2 Sections - East and West of Ibis Street 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction C < C < C < C < C < C < C < C < C < C < C < C C < C < C < C < C < DECIBLE REDUCTION 7.2 WALL LENGTH (FT.) 979 WEST SECTION (FT.) 169 EAST SECTION (FT.) 810 WALL HEIGHT (FT.) 10 WALL COST ($) COST/Dba ($)

30 Area C - North Side - West of Hanson - 2 Sections - East and West of Ibis Street 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction C < C < C < C C C C C < C < C < C < C C < C < C < C < C < DECIBLE REDUCTION 34.8 WALL LENGTH (FT.) 979 WEST SECTION (FT.) 169 EAST SECTION (FT.) 810 WALL HEIGHT (FT.) 15 WALL COST ($) COST/Dba ($)

31 Area C - North Side - West of Hanson - 2 Sections - East and West of Ibis Street 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction C < C < C < C C C C C < C < C < C < C C < C < C < C < C < DECIBLE REDUCTION 41.9 TOTAL WALL LENGTH (FT.) 979 WEST SECTION (FT.) 169 EAST SECTION (FT.) 810 WALL HEIGHT (FT.) 20 WALL COST ($) COST/Dba ($)

32 Area D - South Side - West of Hanson 13' Noise Wall - Cost Reasonableness Assessment Receptor No wall 13' wall Noise Reduction Residences Total Reduction D < D D D D D D D D < D < D < D < D < D D < D D < D < D < D < DECIBLE REDUCTION 59.3 WALL LENGTH (FT.) 956 WALL HEIGHT (FT.) 13 WALL COST ($) COST/Dba ($)

33 Area D - South Side - West of Hanson 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction D < D < D D D < D < D < D D < D < D < D < D < D < D < D < D < D < D < D < DECIBLE REDUCTION 18.4 WALL LENGTH (FT.) 956 WALL HEIGHT (FT.) 10 WALL COST ($) COST/Dba ($)

34 Area D - South Side - West of Hanson 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction D < D D D D D D D D < D < D < D < D < D D < D D < D < D < D < DECIBLE REDUCTION 67.3 WALL LENGTH (FT.) 956 WALL HEIGHT (FT.) 15 WALL COST ($) COST/Dba ($)

35 Area D - South Side - West of Hanson 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction D < D D D D D D D D < D < D < D < D < D D D D < D < D < D < DECIBLE REDUCTION 84.9 WALL LENGTH (FT.) 956 WALL HEIGHT (FT.) 20 WALL COST ($) COST/Dba ($)

36 Area E - North Side - East of Hanson 11' Noise Wall - Cost Reasonableness Assessment Receptor No wall 11' wall Noise Reduction Residences Total Reduction E < E E < E E DECIBLE REDUCTION 45.2 WALL LENGTH (FT.) 607 WALL HEIGHT (FT.) 11 WALL COST ($) Easement Cost 5000 COST/Dba ($)

37 Area E - North Side - East of Hanson 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction E < E < E < E < E DECIBLE REDUCTION 16.5 WALL LENGTH (FT.) 607 WALL HEIGHT (FT.) 10 WALL COST ($) Easement Cost 5000 COST/Dba ($)

38 Area E - North Side - East of Hanson 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction E < E E < E E DECIBLE REDUCTION 60.5 WALL LENGTH (FT.) 607 WALL HEIGHT (FT.) 15 WALL COST ($) Easement Cost 5000 COST/Dba ($)

39 Area E - North Side - East of Hanson 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction E < E E < E E DECIBLE REDUCTION 69.2 WALL LENGTH (FT.) 607 WALL HEIGHT (FT.) 20 WALL COST ($) Easement Cost 5000 COST/Dba ($)

40 Area F - South Side - East of Hanson 10' Noise Wall - Cost Reasonableness Assessment Receptor No wall 10' wall Noise Reduction Residences Total Reduction F < F < F < F < F F F < DECIBLE REDUCTION 22.0 WALL LENGTH (FT.) 595 WALL HEIGHT (FT.) 10 WALL COST ($) COST/Dba ($)

41 Area F - South Side - East of Hanson 15' Noise Wall - Cost Reasonableness Assessment Receptor No wall 15' wall Noise Reduction Residences Total Reduction F < F < F < F < F F F < DECIBLE REDUCTION 34.2 WALL LENGTH (FT.) 595 WALL HEIGHT (FT.) 15 WALL COST ($) COST/Dba ($)

42 Area F - South Side - East of Hanson 20' Noise Wall - Cost Reasonableness Assessment Receptor No wall 20' wall Noise Reduction Residences Total Reduction F < F < F < F < F F F < DECIBLE REDUCTION 40.0 WALL LENGTH (FT.) 595 WALL HEIGHT (FT.) 20 WALL COST ($) COST/Dba ($)