TRAFFIC NOISE ANALYSIS GLENN HIGHWAY RECONSTRUCTION MILEPOST 34 42 PARKS HIGHWAY TO OLD GLENN HIGHWAY PROJECT NO. 58104/NH 0A1 5(24) PREPARED FOR ALASKA DEPARTMENT OF TRANSPORTATION & PUBLIC FACILITIES PREPARED BY HATTENBURG DILLEY & LINNELL, LLC 3335 ARCTIC BLVD., SUITE 100 ANCHORAGE, AK 99503 JUNE 2015
Glenn Highway Reconstruction Milepost 34-42 TABLE OF CONTENTS ACRONYMS... III ACOUSTICAL TERMINOLOGY... IV EXECUTIVE SUMMARY... V 1.0 INTRODUCTION... 1 1.1 Project Description... 1 1.2 Purpose of Study... 2 1.3 Project Background... 2 1.4 Terminology... 3 2.0 ELEMENTS OF TRAFFIC NOISE... 4 3.0 METHODS... 4 3.1 DOT&PF and FHWA Noise Level Criteria... 5 4.0 EXISTING CONDITIONS... 7 4.1 Description of Land Use Categories Along the Corridor... 7 4.2 Noise Measurement Procedures... 8 4.3 Model and Validation Process... 11 4.4 Traffic Parameters... 11 5.0 NOISE IMPACTS... 12 5.1 Traffic Noise Impacts... 12 5.2 Construction Noise Impacts... 13 6.0 ABATEMENT RECOMMENDATIONS... 14 6.1 Feasibility and Reasonableness... 14 6.1.A Cost Per Benefitted Receptor... 14 6.2 Traffic Noise Mitigation... 15 6.2.A Noise Abatement Analysis... 15 6.2.B Other Mitigation Methods... 17 6.3 Construction Noise Mitigation... 18 7.0 STATEMENT OF LIKELIHOOD... 19 8.0 CONCLUSION... 19 9.0 LIST OF PREPARERS... 20 10.0 REFERENCES... 20 I
TABLES TABLE 1: 1989 NOISE ANALYSIS RESULTS... 2 TABLE 2: TYPICAL SOUND LEVELS FOR COMMON NOISE SOURCES... 4 TABLE 3: FHWA LAND USE ACTIVITY CATEGORIES... 6 TABLE 4: NAC THRESHOLDS FOR UNDEVELOPED LANDS... 8 TABLE 5: COMPARISON OF MEASURED AND PREDICTED TRAFFIC NOISE LEVELS... 11 TABLE 6: VEHICLE VOLUME, MIX, AND DIRECTIONAL SPLITS USED IN TNM... 11 TABLE 7: EXISTING, FUTURE NO BUILD, AND BUILD PEAK HOUR NOISE LEVELS... 12 TABLE 8: CONSTRUCTION EQUIPMENT NOISE... 13 TABLE 9: ENGINEERING FEASIBILITY... 16 TABLE 10: ACOUSTIC FEASIBILITY... 16 TABLE 11: BARRIER COST EFFECTIVENESS... 17 FIGURES FIGURE 1:... LOCATION AND VICINITY MAP FIGURE 2:... TYPICAL SECTIONS FIGURES 3 8:... NOISE ANALYSIS SITES FIGURE 9:... NOISE SENSITIVE AREAS FIGURES 10 13:... UNDEVELOPED LANDS: CATEGORY G APPENDICES APPENDIX A... MEASUREMENT AND RECEPTOR SITE DETAILS, FIELD DATA APPENDIX B:... DOT&PF CORRESPONDENCE APPENDIX C:... NOISE ABATEMENT RECOMMENDATION WORKSHEETS APPENDIX D:... DOT&PF NOISE POLICY II
ACRONYMS ANSI... American National Standards Institute CFR... Code of Federal Regulations dba... Decibels, A weighted db... Decibels DOT&PF... Department of Transportation and Public Facilities EA... Environmental Assessment FHWA... Federal Highway Administration FONSI... Finding of No Significant Impact Leq... Equivalent Steady State Sound Level MP... Milepost MSB... Matanuska Susitna Borough NAC... Noise Abatement Criteria NHS... National Highway System TDM... Transportation Demand Management TNM... Traffic Noise Model TSM... Transportation System Management SQ FT... Square Feet YMCA... Young Men s Christian Association U.S.... United States III
ACOUSTICAL TERMINOLOGY Ambient Noise Level All encompassing noise (level) at a given place and time, usually a composite of sounds from all sources near and far, including any specific source(s) of interest. A Weighted Sound Level (dba) Frequency weighted sound level approximating the frequency response of the human ear. It is defined as the sound level, in decibels, measured with a sound level meter having the metering characteristics and a frequency weighting specified in the American National Standards Institute Specification for Sound Level Meters ANSI S 1.4 1983. The A weighting de emphasizes lower frequency sounds below 1000 Hz (1 khz) and higher frequency sounds above 4 khz. A weighting is the most generally used measure for traffic and environmental noise throughout the world. Benefitted Receptor The recipient of an abatement measure that receives a noise reduction at or above the minimum threshold of 5 dba. Decibel (db) A decibel is one tenth of a Bel. It is a measure on a logarithmic scale which indicates the squared ratio of sound pressure to a reference sound power (unit for sound power level). Day Night Noise Level (Ldn) A noise level that takes into account all the A weighted noise energy from a source during 24 hours and weights the nighttime (10 p.m. to 7 a.m.) noise by adding 10 dba, during that period. Existing Noise Levels The noise, resulting from the natural and mechanical sources and human activity, considered to be usually present in a particular area. Leq The equivalent steady state sound level, which in a stated period of time would contain the same acoustical energy as the time varying sound level during the same time period. Lmax The highest sound pressure level in a specific time period. Ln The sound pressure level exceeded "n" percent of a specific time period. Nomograph a graphical calculating device, a two dimensional diagram designed to allow the approximate graphical computation of a function. Noise Sensitive Area A geographic location chosen to represent a worst case noise scenario for any of the land use Activity Categories found along the project corridor, in accordance with the Alaska Department of Transportation and Public Facilities Noise Policy. May contain multiple discrete receptors or be attributed multiple receptors based on Activity Category. Receiver A location at which sound measurements were taken and then used to validate the Traffic Noise Model. Receptor A discrete and representative location of a noise sensitive area(s), for any of the land uses listed in Table 3. IV
EXECUTIVE SUMMARY The Alaska Department of Transportation and Public Facilities proposes to improve the Glenn Highway from the Parks Highway interchange to the Old Glenn Highway in Palmer, Alaska. This highway traffic noise analysis evaluates the potential for traffic noise impacts and noise mitigation options in accordance with the Department of Transportation and Public Facilities Noise Policy (April 2011). Traffic noise levels were measured at seven representative locations in the project area. Vehicle counts and classifications were performed at these sites for use in validating the Federal Highway Administration Traffic Noise Model Version 2.5. The design year used for the purpose of this analysis to predict future traffic noise levels is 2034. Noise levels at five additional noise sensitive areas were modeled for The existing year (2012). The design year build alternative (2034). The design year no build alternative (2034). This traffic noise analysis conforms to Federal Highway Administration and Department of Transportation and Public Facilities traffic noise analysis guidelines and requirements. The table below presents a summary of the noise analysis results for the Federal Highway Administration Activity Categories eligible for noise abatement within the project corridor. The evaluation of existing noise levels yielded one current traffic noise impact at a noise sensitive area. Under the no build alternative, impacts are predicted to exist at three noise sensitive areas; under the build alternative, impacts are predicted to exist at four noise sensitive areas. No feasible and reasonable mitigation options were available for the noise impacts; therefore, no noise abatement is proposed as a part of this project. This recommendation is based on design information and existing policies. SUMMARY OF EXISTING AND PREDICTED NOISE IMPACTS Activity Category Existing Impacts Future No Build Build Alternative Alternative Impacts Impacts B 1 3 3 C 0 0 1 V