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HomeMy WebLinkAbout09 Strander Boulevard Noise Report 3/28/18 Noise Report Strander Boulevard Extension Project City of Tukwila, King County Prepared for: City of Tukwila 6200 Southcenter Boulevard Tukwila, WA 98188 Prepared by: Widener & Associates 1902 120th Place SE Suite 202 Everett, WA 98208 March 2018 This page left blank intentionally for printing purposes. Noise Study: Strander Boulevard Extension i City of Tukwila, King County, WA March 2018 Acronyms dB(A) The A-weighted sound level measured in decibels. A-weighted network = a frequency-equalizing function which approximates the sensitivity of human hearing to sounds of moderate SPL. EB EPA East bound traffic lane Environmental Protection Agency FHWA Federal Highway Administration Leq(1h) The equivalent sound level (the logarithmic sum of sound exposure levels) over 1 hour mph Miles per hour NAC NB Noise Abatement Criteria North bound traffic lane SB South bound traffic lane SEL SPL Sound Exposure Level Sound Pressure Level TNM FHWA traffic noise model – version 2.5 WB West bound traffic lane WSDOT Washington State Department of Transportation Noise Study: Strander Boulevard Extension ii City of Tukwila, King County, WA March 2018 This page left blank intentionally for printing purposes. Noise Study: Strander Boulevard Extension iii City of Tukwila, King County, WA March 2018 Executive Summary Widener & Associates undertook this study to analyze existing and predicted future traffic noise conditions in the vicinity of the proposed Strander Boulevard Extension Project. The entire project consists of constructing a shoofly, excavating an underpass of vehicular and pedestrian traffic, as well as erecting a two-span bridge for the BNSF railroad. Other utility work by BNSF, BP Oil, ATT, SPU, and SPE are also required during the course of the project. Associated construction activities required for the above description have included or will include excavation, utility relocation, railroad shoofly embankment, grading, dewatering, storm sewer, water line, installation of shoring walls and retaining walls, paving, curb and gutter, illumination, striping, and signing. Cities of Renton and Tukwila, Pierce County, WA within Section 25 of Range 4E and Township 23N. Existing land use along the project corridor is divided light industrial and commercial. Sound levels for the 'Existing 2017', 'No Build 2040' and 'Build 2040' conditions were derived from the Traffic Noise Model (TNM) 2.5, verified with field measurements, and compared with the Federal Highway Administration (FHWA) and the Washington State Department of Transportation (WSDOT) standards and criteria. Sound level recording and modeling was undertaken in accordance with FHWA guidelines and standards. A total of eight receivers were modeled within the project area. As per WSDOT guidelines, all receivers were modeled for the worst case hourly condition in the project area as a whole (the PM peak hour). Traffic data was collected in 2017 and forecasted for 'No Build 2040', and 'Build 2040' conditions. This study shows that noise above established thresholds (as defined by FHWA/WSDOT) occurs at three locations along the project corridor. The 2040 Build scenario does not predict a substantial increase over the existing condition at any of the eight receivers. The greatest increase in sound level under the ‘Build 2040’ condition compared to existing conditions is 3 dB at receiver 3. The greatest sound level experienced under the 'Build 2040’ condition is 73 dB(A) at receivers 2 and 7. See table below for modeled results for all conditions. Noise Study: Strander Boulevard Extension iv City of Tukwila, King County, WA March 2018 Summary of results for the Existing, No Build 2040, and Build 2040 conditions Receivers Existing (2017) LAeq1hr No Build (2040) LAeq1hr Build (2040) LAeq1hr Impact Approach Noise Level Criteria Impact Substantial Increase Criteria Number Name/Description V-1 Validation Site 1 75 76 76 - - V-2 Validation Site 2 73 74 74* - - 3 Restaurant 68 70 73 71 10 4 Offices 1 59 60 63 71 10 5 Offices 2 63 64 67 71 10 6 Offices 3 57 58 60 71 10 7 Credit Union 71 72 73 71 10 8 Interurban Trail 66 67 69 66 10 *This location is only used for validation. The noise level in the build condition is only estimated due to proximity to the roadway and is not subject to consideration of abatement measures. Based on the results of this study, abatement measures were fully evaluated in accordance with Federal Highway Administration and Washington State Department of Transportation noise abatement policy. It was concluded that none of the abatement measures are ‘feasible or reasonable’ by Federal Highway Administration/Washington State Department of Transportation criteria. Noise Study: Strander Boulevard Extension v City of Tukwila, King County, WA March 2018 Table of Contents 1. Introduction ............................................................................................................................. 1 1.1 Noise Characteristics and Measurement .......................................................................... 1 1.1.1 Defining Noise .......................................................................................................... 1 1.1.2 Measuring Noise ....................................................................................................... 1 2. Project Description.................................................................................................................. 3 2.1 Location ............................................................................................................................ 3 2.2 Proposed Work ................................................................................................................. 3 3. Criteria for Determining Impacts ............................................................................................ 9 4. Methods................................................................................................................................. 11 4.1 Field Data Collection ..................................................................................................... 11 4.2 Traffic Noise Model ....................................................................................................... 12 4.2.1 Receivers ................................................................................................................. 12 5. Results ................................................................................................................................... 14 5.1 Existing Noise Environment .......................................................................................... 14 5.1.1 Field Measurement.................................................................................................. 14 5.2 Future Noise Environment ............................................................................................. 17 5.3 Summary of Modeled Results ........................................................................................ 18 5.4 Construction Noise ......................................................................................................... 18 Appendix A: Calibration Certificates Appendix B: Data Used in the Model Appendix C: Sound Level Data Sheets Noise Study: Strander Boulevard Extension vi City of Tukwila, King County, WA March 2018 List of Tables Table 1: Sound Pressure Levels of Representative Sounds and Noises ......................................... 2 Table 2: FHWA noise abatement criteria ..................................................................................... 10 Table 3: Summary of results for the Existing, No Build 2040, and Build 2040 conditions ......... 17 Table 4: Typical construction equipment noise levels .................................................................. 19 List of Figures Figure 1: Vicinity Map.................................................................................................................... 5 Figure 2: Land Use Designations .................................................................................................... 7 Figure 3: Receiver Locations ........................................................................................................ 15 Noise Study: Strander Boulevard Extension 1 City of Tukwila, King County, WA March 2018 1. Introduction The purpose of this report is to document and analyze existing traffic noise conditions and predict future traffic noise conditions in the vicinity of the proposed Strander Boulevard Project, in Tukwila, WA. Sound levels for the ‘Existing 2017’, ‘No Build 2040’ and ‘Build 2040’ conditions were compared with the FHWA / WSDOT standards and criteria. Sound levels were derived from the FHWA approved noise model, TNM 2.5. Calculations generated by the model were verified using field measurements in accordance with FHWA and WSDOT requirements. This report was used to determine whether or not noise abatement measures should be warranted as part of the proposed project, and as appropriate, to make recommendations regarding such options. 1.1 Noise Characteristics and Measurement 1.1.1 Defining Noise Noise is defined as unwanted sound (Maekawa and Lord., 1994; Bell et al., 1996; Berglund et al., 1996). Noise is recognized as having both a physical and a psychological component. The physical component is set, while the psychological component (the degree of annoyance) depends on the listener and their physiological and psychological state as well as the frequency and time of the varying pattern of the sound. Low frequency (particularly anthropogenic sources) and impulse sounds are thought to result in higher levels of annoyance (Hall et al., 1981; Maekawa and Lord, 1994; Bell et al., 1996; Berglund et al., 1996). 1.1.2 Measuring Noise When measuring noise, the decibel scale, the A-weighted network, and the descriptor Leq are usually used to describe and quantify the noise levels experienced by a receiver. These descriptors are described in the following paragraphs. The decibel scale is a logarithmic scale, derived from the Pascal scale and based on sound pressure levels (the physical correlate of loudness). The threshold of human hearing is at 20 micropascals or 0 dB. A change of 20 dB corresponds to a ten-fold increase in micropascals. Thus, 20 dB is equivalent to 200 micropascals. However, the decibel scale provides a better approximation of the perception of loudness than the Pascal scale, 1 dB indicates the same fractional change in sound pressure at all levels. Generally, a 3 dB increase is barely perceptible Noise Study: Strander Boulevard Extension 2 City of Tukwila, King County, WA March 2018 to human listeners. A 6 dB increase corresponds to a doubling of the sound pressure; however, a 10 dB increase is necessary for the sound to be perceived as being twice as loud (FHWA, 1995; Maekawa et al., 1994; Boeker and Van Grondelle, 1995). Refer to Table 1 for examples of typical sound source levels. Table 1: Sound Pressure Levels of Representative Sounds and Noises Source Decibels Description Large rocket engine (nearby) Jet take-off (nearby) Pneumatic riveter Jet take-off (60 meters) Construction noise (3 meters) Subway train Heavy truck (15 meters) and Niagara Falls Average factory Normal conversation (1 meter) Quiet office Quiet Library Soft whisper (5 meters) Rustling leaves Normal breathing Hearing threshold 180 150 130 120 110 100 90 80 70 60 50 40 30 20 10 0 Pain threshold Constant exposure endangers hearing Very quiet Barely audible Source: Tipler 1976 The type of weighting curve used in measuring sound is important in determining the accuracy of the result as a measure of the impact of the sound on those hearing it. The frequency of sound determines the ability of the human auditory system to detect it. As the sound of a constant sound pressure level decreases in frequency from about 1 kHz or increases in frequency from about 5 kHz, its perceived loudness decreases. Therefore, in order to measure what is actually being heard by humans, measurement of sound pressure level is adjusted to account for the relative loudness of the frequency through the use of weighting networks (A, B and C) in sound level meters. Networks are based on approximate equal-loudness contours rather than the hearing threshold curve. The A-weighted network is considered to most accurately represent human perception of noise (Maekawa and Lord, 1994; Boeker and Van Grondelle, 1995; Berglund et al., 1996). The descriptor used to measure traffic-induced sound levels in this study is dB(A) Leq(1h), which is defined as the equivalent A-weighted sound level [the logarithmic sum of sound exposure levels (SELs)] over 1 hour. Noise Study: Strander Boulevard Extension 3 City of Tukwila, King County, WA March 2018 2. Project Description 2.1 Location The proposed project is located in the Cities of Renton and Tukwila, Pierce County, WA. The legal geographic area is Section 25 of Range 4E and Township 23N. Existing land use along the project corridor is divided light industrial and commercial. Refer to Figure 1 for the project vicinity and Figure 2 for land use designations. 2.2 Proposed Work The entire project consists of constructing a shoofly, excavating an underpass of vehicular and pedestrian traffic, as well as erecting a two-span bridge for the BNSF railroad. Other utility work by BNSF, BP Oil, ATT, SPU, and SPE are also required during the course of the project. Associated construction activities required for the above description have included or will include excavation, utility relocation, railroad shoofly embankment, grading, dewatering, storm sewer, water line, installation of shoring walls and retaining walls, paving, curb and gutter, illumination, striping, and signing. Noise Study: Strander Boulevard Extension 4 City of Tukwila, King County, WA March 2018 This page intentionally left blank for printing purposes. Fi g u r e 1 : V i c i n i t y M a p St r a n d e r B o u l e v a r d E x t e n s i o n P r o j e c t City of Renton Ced a r R i v e r ¯ Th i s p a g e i n t e n t i o n a l l y l e f t b l a n k f o r p r i n t i n g p u r p o s e s . Fi g u r e 2 : L a n d U s e D e s i g n a t i o n s St r a n d e r B o u l e v a r d E x t e n s i o n P r o j e c t City of Renton Th i s p a g e i n t e n t i o n a l l y l e f t b l a n k f o r p r i n t i n g p u r p o s e s . Noise Study: Strander Boulevard Extension 9 City of Tukwila, King County, WA March 2018 3. Criteria for Determining Impacts This section discusses applicable noise regulations and agency guidelines that provide the basis for evaluating potential noise impacts and mitigation or abatement for a proposed project. Noise regulations and guidelines for federally funded highway projects in Washington are established by WSDOT and the FHWA. The FHWA (23 C.F.R. §772.5(g)) defines traffic noise impacts to occur either when: predicted traffic noise levels approach or exceed the noise abatement criteria; predicted traffic noise levels substantially exceed the existing noise levels; or predicted traffic noise levels are severe noise levels WSDOT has defined ‘approach’ to be within 1 dB(A) below the FHWA noise abatement criteria of 67 dB(A) and has defined ‘substantially exceed’ to be a 10 dB(A) increase over existing noise levels. A severe impact is defined as a level greater than 80 dB(A) Leq(1h). Therefore, a noise impact is determined to occur when predicted noise levels ‘approach’ or ‘exceed’ the FHWA noise abatement criteria1 as given in Table 1 or when predicted noise levels are 10 dB(A) or greater over the existing level. For example, traffic noise impacts for Activity Category B (residences, schools etc.) would occur if predicted noise levels were to be equal or greater than 66 dB(A) Leq (1h). 1 Noise standards that specify exterior Leq(h) noise levels for various land activity categories. Noise Study: Strander Boulevard Extension 10 City of Tukwila, King County, WA March 2018 Table 2: FHWA noise abatement criteria Activity Category Leq(1h) dB(A) Description of Activity Category A 57 (exterior) Lands on which serenity and quiet are of extraordinary significance and serve an important public need and where the preservation of those qualities is essential if the area is to continue to serve its intended purpose. B 67 (exterior) Residential (single and multi-family units) C 67 (exterior) Active sports centers, 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, recreational areas, Section 4(f) sites, schools, television studios, trails, and trail crossings. D 52 (interior) Auditoriums, day care centers, hospitals, libraries, medical facilities, places of worship, public meeting rooms, public or nonprofit institutional structures, radio studios, schools, and television studios. E 72 (exterior) Hotels, motels, offices, restaurants/bars, and other developed lands, properties or activities not included in A-D or F. Includes undeveloped land permitted for these activities. F - Agriculture, airports, bus yards, emergency services, industrial, logging, maintenance facilities, manufacturing, mining, retail facilities, shipyards, utilities (water resources, water treatment, and electrical), and warehousing. G - Undeveloped lands that are not permitted Source: 23 C.F.R. Part 772 Sound levels generated by any proposed project are primarily compared to the FHWA / WSDOT standards and criteria rather than to the ‘Existing’ condition or to the ‘No Build 2040’ condition. The project proponent is required to consider mitigation options when the proposed project meets or exceeds FHWA / WSDOT standards and criteria in the future build condition. In a case where the criteria are exceeded by a lesser degree as a result of the proposed project than under the ‘Existing’ condition, the project proponent is still required to consider mitigation options. Noise Study: Strander Boulevard Extension 11 City of Tukwila, King County, WA March 2018 4. Methods 4.1 Field Data Collection Sound levels were recorded in the field on December 30, 2017. Sound level recordings were made at two sites along the project corridor between 1:45 and 3 pm. Refer to Figure 3 and the data sheets provided in Appendix C. Recordings were made using a Larson and Davis Type 1 Sound Level Meter (model 820) and the following variables: Descriptor: Leq Sample rate, 15 minutes Integration rate: Fast Weighting, A The timing and source of other noises perceptible above the traffic noise were also noted. The sound level meter, microphone, and calibrator were within factory calibration. Calibration certificates for the meter, microphone, and calibrator are provided in Appendix A. The microphone was placed 5 feet off the ground and the site chosen was an area of potential outdoor human use (refer to Appendix C). Traffic data collected in the field was used to validate the model in accordance with FHWA and WSDOT requirements. Traffic data and weather conditions collected in the field at the time of the sound recording were entered into the model. The following traffic data and baseline information was collected during each 15-minute sound recording interval: total numbers of each traffic type (automobiles, medium trucks [2 axles and 6 tires] heavy trucks [greater than 2 axles / 6 tires], buses, and motorbikes) directionally separated; average speed temperature humidity Sound levels calculated by the model were compared with those recorded in the field. The acceptable margin of error between the field recordings and the modeled results were plus or minus 2 dB(A). The difference between the field recordings and modeled results for all sites were within 2 dB(A). Noise Study: Strander Boulevard Extension 12 City of Tukwila, King County, WA March 2018 4.2 Traffic Noise Model The FHWA traffic noise model version 2.5 (TNM) was used to model the existing and future (‘Build 2040’ and ‘No Build 2040’) road traffic-induced noise environment within the project area. 4.2.1 Receivers A total of eight receivers were modeled. All but one of these receivers are characterized as ‘Activity Category E’ receivers. For all Category E receivers, the impact criterion is 71 dB(A). One receiver is characterized as a ‘Activity Category C’ receiver. The impact criterion is 66dB(A). Receivers were chosen based on the following factors: 1. Proximity to the existing and proposed roadway. Sites most likely to be impacted were favored. 2. Location along the corridor. Receivers were selected along the length of the project corridor and extend out from the road to such a distance to ensure that all traffic noise impacts are included. Modeling limits are extended to reach any location which reaches 65 dB(A) to ensure the full impacted area is captured. 3. Primary areas of outdoor use. Receivers were placed at sites which appeared to have the most foot traffic. 4. Sites which would be removed as a result of the proposed project or which were too close to the roadway to model were not selected. As per WSDOT guidelines, all receivers were modeled for the worst case condition in the project area as a whole (the PM peak hour) for 2017 and 2040. Noise Study: Strander Boulevard Extension 13 City of Tukwila, King County, WA March 2018 4.2.2 Traffic Data 4.2.2.1 Existing Condition Traffic Data Traffic data for the PM Peak Hour were provided by Fehr and Peers based on tube counts conducted within the project corridor. Traffic was directionally separated and provided percentages of vehicle type (Refer to Appendix B). Speeds along the corridor were based on posted speed limits. 4.2.2.2 No Build 2040 Condition Traffic numbers on existing roads were used to predict traffic numbers on the new road by Fehr and Peers. Percentages of vehicle types were assumed to be the same as for the ‘Existing 2017’ condition. Refer to Appendix B for the traffic data and the vehicle percentages used to model the ‘No Build 2040’ condition. The posted speed for each roadway was used, resulting in the worst hourly noise conditions. 4.2.2.3 Build 2040 Condition Predicted counts were also used to model the ‘Build 2040’ condition. Percentages of vehicle types were assumed to be the same as for the ‘Existing 2012’ and ‘No Build 2040’ conditions. The proposed posted speed for the new roadway. Remaining roadways were assumed to have the same posted speed. Refer to Appendix B for the data used to model the ‘Build 2040’ condition. Noise Study: Strander Boulevard Extension 14 City of Tukwila, King County, WA March 2018 5. Results 5.1 Existing Noise Environment 5.1.1 Field Measurement Sound levels were recorded in the field at two sites along the project corridor. Data from the site was compared to the modeled results (based on traffic data collected during the sound level recording) in order to validate the model in accordance with WSDOT requirements. WSDOT requires that the modeled results and the field measurements come within plus or minus 2 dB(A) of one another. Site one (Receiver 1) was located on the sidewalk south of the intersection of W Valley Highway and Strander Boulevard. Site two (Receiver 2) was located on the east side of the project on SW 27th Street near the intersection with Naches Avenue SW. These sites were chosen as they represent the conditions within the project area, however they do not require noise abatement consideration. The Leq levels measured in the field were 71.4 dB(A) for site one. The Leq levels calculated by the model were 70.2 dB(A) for site one. The Leq levels measured in the field were 61.8 dB(A) for site two. The Leq levels calculated by the model were 59.9 dB(A) for site two. Therefore, the result is within the acceptable margin of error and modeling of all receivers under all conditions (Existing, No Build, and Build) could proceed. The meter was correctly calibrated at the time of recording. All field validation sites are depicted in Figure 3. Environmental conditions recorded during field measurements are as follows: Temperature, 49°F; Relative Humidity, 65%; Sound levels at the field recording site was dominated by vehicular traffic. Refer to the data sheets provided in Appendix C. !( !( !( !( !( !( !( 3 7 6 5 4 V-1 V-2 Figure 3: Receiver LocationsStrander Boulevard Extension ProjectCity of Renton March 2017 SW 2 7 t h S t r e e t Strande r B o u l e v a r d W e s t V a l l e y H i g h w a y ¬«181 !(Receiver !(Validation Proposed Road Ü 0 250 500125Feet 1 inch = 250 feet Th i s p a g e i n t e n t i o n a l l y l e f t b l a n k f o r p r i n t i n g p u r p o s e s . Noise Study: Strander Boulevard Extension 17 City of Tukwila, King County, WA March 2018 5.2 Future Noise Environment Of the eight receivers modeled, three exceeded the FHWA/WSDOT sound level criteria under the build condition. Receivers 7 and 8 exceeded the sound level criteria under all conditions. Refer to Table 3 for the results of existing sound levels modeled at all receivers and to Figure 3 for the locations. The 2040 Build scenario does not predict a substantial increase over the existing condition at any of the eight receivers. The greatest increase in sound level under the ‘Build 2040’ condition compared to existing conditions is 5 dB at receiver 3. The greatest sound level experienced under the 'Build 2040' condition is 73 dB(A) at receivers 3 and 7. Table 3: Summary of results for the Existing, No Build 2040, and Build 2040 conditions Receivers Existing (2017) LAeq1hr No Build (2040) LAeq1hr Build (2040) LAeq1hr Impact Approach Noise Level Criteria Impact Substantial Increase Criteria Number Name/Description 1 Validation Site 1 75 76 76 - - 2 Validation Site 2 73 74 74* - - 3 Restaurant 68 70 73 71 10 4 Offices 59 60 63 71 10 5 Offices 2 63 64 67 71 10 6 Office 3 57 58 60 71 10 7 Credit Union 71 72 73 71 10 8 Interurban Trail 66 67 69 66 10 *This location is only used for validation. The noise level in the build condition is only estimated due to proximity to the roadway and is not subject to consideration of abatement measures. Noise Study: Strander Boulevard Extension 18 City of Tukwila, King County, WA March 2018 5.3 Summary of Modeled Results This study shows that noise above established thresholds (as defined by FHWA/WSDOT) occur at three locations along the project corridor. The 2040 Build scenario does not predict a substantial increase over the existing condition at any of the eight receivers. The greatest increase in sound level under the ‘Build 2040’ condition compared to existing conditions is 5 dB at receiver 3. The greatest sound level experienced under the 'Build 2040' condition is 73 dB(A) at receivers 3 and 7. Based on the results of this study, receivers experience traffic noise impacts as a result of the proposed project and therefore require abatement consideration in accordance with FHWA and WSDOT policy. 5.4 Construction Noise Short-term noise impacts would occur as a result of construction activities. General construction activities (such as grading, laying base, and paving) would take place as part of the proposed project. Based on WSDOT guidance, short-term noise impacts are expected to radiate up to a maximum of one mile from the project area. Based on the data tabulated by the Environmental Protection Agency (EPA) and WSDOT, sound levels generated during construction are not expected to exceed 95 dB(A). Construction equipment sounds (usually point source) decrease about 6 dB(A) with every doubling of distance. Table 4 depicts typical construction equipment sound levels 50 feet from there source. Surrounding areas would temporarily experience higher noise levels as a result of construction. Noise Study: Strander Boulevard Extension 19 City of Tukwila, King County, WA March 2018 Table 4: Typical construction equipment noise levels 60 70 80 90 100 110 Compactors (rollers) Front-end loaders Backhoes Tractors Scrapers, graders Pavers Trucks Concrete mixers Concrete pumps Cranes (movable) Cranes (derrick) Pumps Generators Compressors Pneumatic wrenches Jack hammers, rock drills Pile drivers (peaks) Vibrator Saws Eq u i p m e n t T y p e Noise Level (dBA) at 15 meters (50 ft.) Ea r t h M o v i n g Ma t e r i a l s H a n d l i n g St a t i o n a r y Im p a c t Ot h e r Source: EPA, 1971 and WSDOT, 1991. The City of Tukwila’s noise ordinance, chapter 8.22.110, define the following as exempt during daytime hours: 3. Sounds created by construction or the movement of construction-related materials, including but not limited to, striking or cutting sounds from hammers, saws or equipment with electrical or internal combustion engines emanating from temporary construction sites. As defined in chapter 8.22.020: “Daytime” means 7AM-10PM, Monday through Friday and 8AM-10PM, Saturday, Sunday and State-recognized holidays. Noise Study: Strander Boulevard Extension 20 City of Tukwila, King County, WA March 2018 None of the areas around the project are zoned for residential use; no potential impacts to residential zones is possible. The construction noise from this project is exempt from the City of Tukwila and Renton’s municipal code during daytime hours and is not required to be mitigated. However, there are some simple techniques that can be put into place to reduce the noise impacts for nearby offices or people passing by the construction area: Minimize construction noise by turning off engines when not in use. Back up alarms can produce some objectionable sound, although they are exempt from the state noise ordinance. It is recommended that vehicles drive forward as much as possible to avoid the use of back-up alarms. Substitute hydraulic or electric models for impact tools such as rock drills or jackhammers. Noise Study: Strander Boulevard Extension 21 City of Tukwila, King County, WA March 2018 6. Mitigation Needs As discussed in Section 3, the project proponent is required to consider mitigation options when the proposed project meets or exceeds FHWA/ WSDOT criteria/standards regardless of whether or not the criteria/standards were met or exceeded under the ‘Existing’ condition. As this study identifies noise impacts, mitigation measures need to be fully evaluated in accordance with FHWA and WSDOT noise abatement policy for receivers that would be impacted by the proposed project. FHWA and WSDOT require that construction of noise barriers be evaluated for feasibility and reasonableness. Feasibility deals primarily with engineering considerations such as whether or not a substantial reduction in sound levels can be achieved and whether or not abatement measures would affect property access. To be feasible, a noise wall must be constructed to achieve a reduction of at least 5 dB(A) for the majority of impacted first row receivers. Reasonableness assesses the practicality of the abatement measure including: cost, the amount of noise reduction, and future traffic levels. To be reasonable, a noise reduction of at least 7 dB(A) at one sensitive receiver must be achieved. The WSDOT noise mitigation cost per residence is given in the following table. Table 5: Noise mitigation cost per residence Design Year Traffic Noise Decibel Level Allowed Cost Per Household * Equivalent Wall Surface Area Per Household 66 dBA $36,127 700 ft2 67 dBA $39,636 768 ft2 68 dBA $43,146 836 ft2 69 dBA $46,665 904 ft2 70 dBA $50,165 972 ft2 71 dBA $53,674 1040 ft2 72 dBA $57,184 1108 ft2 73 dBA $60,693 1176 ft2 74 dBA $64,203 1244 ft2 *Reevaluated each year. Based on $51.61 per square foot constructed cost (WSDOT, 2011) Note: the allowed cost per household (or residential equivalent) can be used for the full range of mitigation options including the construction of barriers and the acquisition of property. Noise Study: Strander Boulevard Extension 22 City of Tukwila, King County, WA March 2018 There are three receivers which meet or exceed noise level criteria. These receivers are a credit union office, the interurban trail, and fast food restaurant which are designated as Category E receivers. In order to maintain access to these businesses and their parking lots, a noise wall is not feasible. The Interurban Trail runs parallel to the W Valley Highway in this location and will be rerouted at the crossing of Strander Boulevard during project construction. No feasible wall location exists which would reduce noise from W Valley Highway and access across Strander Boulevard must be maintained. Noise Study: Strander Boulevard Extension 23 City of Tukwila, King County, WA March 2018 References 23 C.F.R. Part 772, Procedures for Abatement of Highway Traffic Noise and Construction Noise Bell, P.A., Greene, T.C., Fisher, J.D., Baum, A., 1996, Environmental Psychology 4th Ed. Harcourt Brace College Publishers, Florida, USA. Berglund, B., Hassmen, P., Job, R. F. S., 1996, 'Sources and effects of low-frequency noise'. Journal of the Acoustical Society of America, v99, n5, p2985 - 3002. Boeker, E., Van Grondelle, R., 1995, Environmental Physics. John Wiley & Sons Ltd, UK. City of Tukwila, Municipal Code. Title 8. Accessed on March 19, 2018. http://records.tukwilawa.gov/weblink/1/edoc/56243/Tukwila%20Municipal%20Code%2 0-%20Title%2008%20-%20Public%20Peace%20and%20Safety.pdf City of Renton. 2015. Zoning Map. Accessed March 19, 2018. https://www.rentonwa.gov/UserFiles/Servers/Server_7922657/File/City%20Hall/Administrative %20Services/Information%20Technology/GIS/Zoning.pdf City of Tukwila. 2015. Zoning Map. Accessed March 19, 2018. http://www.tukwilawa.gov/wp-content/uploads/Comp-Plan_Zoning-Map.pdf FHWA, June 1995, Highway Traffic Noise Analysis and Abatement Policy and Guidance, USDOT, FHWA, Office of Environment and Planning, Noise and Air Quality Branch, Washington DC Hall, F.L., Birnie, S., Taylor, M., Palmer, J.E., 1981, 'Direct comparison of community response to road traffic noise and to aircraft noise'. Journal of the Acoustical Society of America, v70, n6, p1690-1698. Maekawa, Z., Lord, P., 1994, Environmental and Architectural Acoustics. E & FN SPON, London, UK. WSDOT. 2011 Traffic Noise Policy and Procedures. July 13. Noise Study: Strander Boulevard Extension 24 City of Tukwila, King County, WA March 2018 This page intentionally left blank for printing purposes. Appendix A: Calibration Certificates This page intentionally left blank for printing purposes. Appendix B: Data Used in Model This page intentionally left blank for printing purposes. Existing Conditions Total Heavy Trucks Med Trucks Cars 27th ST WB 180 9 16 155 27th ST EB 455 18 41 396 000 Strander WB 3 315 16 28 271 Strander EB 3 361 14 32 314 Strander WB 2 51 3 5 44 Strander EB 2 61 2 5 53 Strander WB 1 712 7 43 662 Strander EB 1 697 77 42 579 W Valley Hwy NB 1 1413 57 99 1258 W Valley Hwy SB 1 1424 57 71 1296 W Valley Hwy NB 2 1273 64 102 1108 W Valley Hwy SB 2 1018 41 92 886 No Build 2040 Total Heavy Trucks Med Trucks Cars 27th ST WB 240 12 22 206 27th ST EB 630 25 57 548 000 Strander WB 3 410 21 37 353 Strander EB 3 395 16 36 344 Strander WB 2 80 4 7 69 Strander EB 2 90 4 8 78 Strander WB 1 950 10 57 884 Strander EB 1 1030 113 62 855 W Valley Hwy NB 1 1820 73 127 1620 W Valley Hwy SB 1 1700 68 85 1547 W Valley Hwy NB 2 1710 86 137 1488 W Valley Hwy SB 2 1660 66 149 1444 Build 2040 Total Heavy Trucks Med Trucks Cars 27th ST WB 760 38 68 654 27th ST EB 1230 49 111 1070 000 Strander WB 3 1080 54 97 929 Strander EB 3 1120 45 101 974 Tukwila Access NB 40 2 4 35 Tukwila Access SB 370 15 33 322 Strander WB 2 1230 62 111 1058 Strander EB 2 930 37 84 809 Strander WB 1 1390 14 83 1293 Strander EB 1 1290 142 77 1071 W Valley Hwy NB 1 2160 86 151 1922 W Valley Hwy SB 1 1830 73 92 1665 W Valley Hwy NB 2 1670 84 134 1453 W Valley Hwy SB 2 1540 62 139 1340 Appendix C: Sound Level Data Sheets This page intentionally left blank for printing purposes.