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4.8 NO/Se The proposed project and two related projects with residential components identified in Table 3-3 in Chapter 3.0 (Project Description) are located within close proximity to the AT&SF rail line. Problems for residential uses, such as disturbance due to groundborne vibration from these sources, are usually contained to areas within about 200 feet of the vibration source (HMMH 2O06). Typically, the main effect of groundborne vibration is to cause annoyances for occupants of nearby buildings. The effect of vibration at each related project site is site specific and is dependent on existing localized conditions. However, as none of the related projects are located within 100 feet of the railroad right of way, impacts associated with vibration from the tracks are expected to be less than significant. As discussed in Impact 4.8-4, the occupants of the proposed residential units within the Transit Zoning Code (SD 84A and SD 8413) area would not be exposed to potentially significant vibration levels. Therefore, this impact would be less than significant. As discussed in Impact 4.8-7, noise impacts as the result of increased traffic on local roadways was analyzed both for near -term project plan completion (2030) and long range (2035) conditions. The near - term (2030) analysis included both ambient growth and development of the related projects provided in Table 3-3 in Chapter 3.0 (Project Description). The long range (2035) analysis included data obtained from the OCTAM 3.2 travel demand forecasting model which utilizes the latest adopted demographic forecasts for the City. As a result both the near -term (2030) analysis and the long range (2035) analysis are cumulative in nature. As discussed above, cumulative traffic would not result in substantial increases in noise along any roadway segments under either near -term (2030) or long-range (2035) conditions. Roadway noise under either scenarios with the project would not increase roadway noise levels above the 3.0 dBA CNEL significance threshold in areas where existing noise levels meet or exceed the 65 dBA CNEL standard for sensitive uses, or above the 5.0 dBA CNEL significance threshold in areas where existing noise levels are below the 65 dBA CNEL standard. Likewise, the contribution of the proposed project to this increase under both scenarios would not exceed 3.0 dBA or 5.0 dBA CNEL. As a result, the contribution of the proposed project to future roadway noise levels would not exceed the identified thresholds of significance and, therefore, would not be considered cumulatively considerable and the cumulative impact would be less than significant. The proposed project and two related projects with residential components are located within close proximity to the AT&SF rail line. Sensitive receptors, including residential uses with exterior uses such as communal areas consisting of pocket parks or pedestrian walkways and private balconies, may or may not be shielded from noise generated by railroad operations. As a result, noise levels within these areas may exceed the 65 dBA CNEL "Desirable Maximum" standard, and this would be considered a significant and unavoidable cumulative impact. Mitigation measures MM4.8-5, MM4.8-6, and MM4.8-8 would reduce noise levels at these receptors but not to a less -than -significant level. Periodic and temporary noise levels would be generated by construction of individual projects along with other construction in the vicinity. As discussed in Impact 4.8-1, these projects by themselves would expose some receptors to noise levels in excess of acceptable City standards. Construction noise impacts are localized in nature and decrease substantially with distance. Consequently, in order to achieve a substantial cumulative increase in construction noise levels, more than one source emitting high levels of City of Santa Ana Transit Zoning Code (SD 84A and SD 848) EIR 4.8-41