T.F. Green Airport Improvement Program - FEIS Chapters - PVD

T.F. Green Airport Improvement ProgramEnvironmental Impact Statement and Final Section 4(f) Evaluationareas where outdoor activity occurs. The applicable NAC for exterior activities in Category B is 67 dBA L eq(h)(refer to Table A.4-2 of the DEIS Noise Supporting Attachment A.4, Vehicular Traffic Noise Technical Report).RIDOT defines the word "approach" to mean when the loudest-hour L eqequals 1 dB less than the NAC.Therefore, noise impact occurs when future build noise levels equal or exceed 66 dBA L eq, for ActivityCategory B. RIDOT analysis is consistent with FHWA protocol for conducting vehicular traffic noise impactassessments.Vehicular traffic-related noise impact also occurs when predicted design year noise levels substantially exceedbaseline noise levels. RIDOT uses a sliding scale that is based on baseline noise levels to define a “substantial”increase. Because noise barriers generally provide noise reductions of between 5 and 10 dB, they are not usuallyconsidered effective in quieter areas. A substantial increase as defined by RIDOT policy for the land uses affected bythis project is equal to or greater than 10 dB or more. For Category B land uses, wherever the predicted design-yearbuild alternative noise levels during the loudest hour of the day either (1) equal or exceed 66 dBA L eq, or (2) cause asubstantial increase over baseline noise levels, then consideration of vehicular traffic noise abatement measures isnecessary. Noise abatement will be considered reasonable and feasible unless it is found that such mitigationmeasures will cause adverse social, economic, or environmental effects that outweigh the benefits received.5.3.4 Impact AssessmentThis section presents the results of the noise impact assessment for the No-Action Alternative andAlternatives B2 and B4 in 2015, 2020, and 2025. Appendix F, Noise, provides further details, where noted.5.3.4.1 No-Action AlternativeThis section presents the results of the noise analysis for the No-Action Alternative in 2015, 2020, and 2025 tocompare to Alternatives B2 and B4 in order to assess potential project-related impacts.Population and Housing Impacts (Aircraft Noise Exposure) – 2015, 2020, and 2025Figure 5-7 depicts a comparison of the aircraft noise-exposure contours for the No-Action Alternative in 2015, 2020,and 2025. Table 5-8 summarizes the housing units that would be exposed to aircraft noise levels of 60 dB or moreunder the No-Action Alternative in 2015, 2020, and 2025. Table 5-9 summarizes the population that would beexposed to aircraft noise levels of 60 dB or more under the No-Action Alternative in 2015, 2020, and 2025.In 2015, under the No-Action Alternative, there would be an estimated 850 housing units (with an estimated 1,998people) located in areas within the contour encompassing DNL 65 dB and above. No people and no housing unitswould be exposed to aircraft noise levels between DNL 70 and 75 dB under the No-Action Alternative in 2015,2020, or 2025. These numbers exclude the number of people that would be relocated and the number of housingunits assumed to be acquired by 2015 under the Completed and Current Part 150 VLAPs (RIAC’s ongoing Part 150NCP). The residential areas included in these VLAP areas are shown on Figure 5-8. The population exposed tonoise levels of DNL 65 dB or above is projected to increase to 1,290 housing units (with an estimated 2,472 people)and 1,414 housing units (with an estimated 3,323 people) in 2020 and 2025, respectively, due to the increase in thenumber of aircraft operations over time unrelated to the Improvement Program.Chapter 5 - Environmental Consequences 5-17 July 2011\\mawatr\ev\09228.00\reports\FEIS_Final_July_2011\PVD_CH05_Environmental_Cons_JUL_2011.doc