The Portland Transit Mall Impact Study \u2013 Noise Impact Report

Federal Transit Administration 50th Anniversaryhttps://doi.org/10.21949/15273731981PDFTech ReportCity of Portland (Oregon). Bureau of PlanningUnited States. Urban Mass Transportation AdministrationUnited States. Department of TransportationPortland (Or.). Bureau of PlanningPortland (Oregon);United StatesUrban transitPublic transitNoiseTraffic noiseImpact studiesSound levelTransit mallsEnvironmentHighwaysPlanning and ForecastingPublic TransportationThe primary purpose of this report is to determine what impacts, if any, the Portland Transit Mall has had on noise levels both on the Mall and on adjacent streets off the Mall. The noise impacts were determined by comparing noise measurements taken before the Mall was constructed to measurements taken after its completion. These comparisons were made in anticipation of being able to detect consistent patterns of change in noise levels after the Mall was built. Noise in downtown Portland is primarily the result of vehicular traffic sources. Therefore, any changes in noise levels resulting from these comparisons are assumed to be directly related to vehicular traffic noise, and to changes in the composition (particularly bus and non-bus) of vehicular traffic. The report presents the comparisons and the resulting changes in noise levels, but does not analyze traffic counts or patterns as a means of explaining these changes. A secondary purpose of this report is to discuss the significance of the noise levels in downtown Portland with the Transit Mall. These noise levels accurately predict the noise impacts which a transit mall similar to the Portland Transit Mall will have in any city, particularly in a downtown area. The report is composed of seven sections . Section I introduces the problem of noise, particularly urban noise, and the measurement and description of noise. Section II briefly discusses three separate sets of noise standards which are relevant to the Portland Transit Mall. Section III outlines the three sources of before-Mail and after-Mall noise measurements, and Section IV presents each of nine noise comparisons made for this study. Section V presents the findings of the noise comparisons, and Section VI concludes the text of the report. Section VII is the Appendix which describes in detail noise measurement data sources which are outlined in Section III.138