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Chapter 4 Environmental Setting, Impacts, and Mitigation Measures would not be cumulatively considerable and the cumulative impact of the project would also be less than significant As discussed under Impact 4.8-2, all rooftop HVAC equipment would be shielded; therefore, no source would generate maximum noise levels of greater than 57 dBA Leg at 50 feet. Consequently, multiple units would have to be located within 50 feet of a receptor to achieve noise levels that would exceed the City standards. The development types associated with the proposed project and other nearby projects are not so dense that multiple stationary units would be so closely spaced, either on -site or off -site. Consequently, the cumulative effect of multiple HVAC units and other mechanical equipment would be less than significant and the contribution of the project would not be cumulatively considerable. This would be a less than signiitcantimpact. As discussed in Impact 4.8-9, the construction of individual projects pursuant to the Transit Zoning Code would produce temporary vibration impacts. However, as discussed in Impact 4.8-9, the construction vibration impact would be significant and unavoidable. Cumulative development in the City of Santa Ana is not considered likely to result in the exposure of on -site or off -site receptors to excessive groundborne vibration due to the localized nature of vibration impacts, the fact that all construction would not occur at the same time and at the same location, and the largely built -out nature of the City, which would usually preclude the use of heavy equipment such as bulldozers. Other projects listed in Table 3-3 in Chapter 3.0 (Project Description) are proposed in close enough proximity to affect the same receptors as the proposed project. Only receptors located in close proximity to each construction site would be potentially affected by each activity. Construction activities associated with these projects, which are adjacent to or within, the Transit Zoning Code (SD 84A and SD 8413) area, may overlap with construction activities for other projects for some amount of time. Sensitive uses in the immediate vicinity of the Transit Zoning Code (SD 84A and SD 8413) area may be exposed to two sources of groundborne vibration. However, for the combined vibration impact from the two projects to reach cumulatively significant levels, intense construction from both projects would have to occur simultaneously within 50 feet of any receptor. As individual development projects under the Transit Zoning Code (SD 84A and SD 84B) area may be constructed concurrently with each other or other related projects, it is possible that intense construction from two or more projects would simultaneously occur at distances of 50 feet or less from existing nearby receptors. Therefore, vibration from future development could potentially combine with construction vibration of other projects to result in a potentially significant cumulative impact. Nlitigation measures MM4.8-1 through MM4.84 would help reduce this impact, but not to a less than significant level. Therefore, the cumulative impact of the proposed project would be significant and unavoidable. Groundbome vibration could conceivably be generated by operation of projects in the vicinity of the Transit Zoning Code (SD 84A and SD 8413) area. Since no substantial sources of groundborne vibration would be built as part of the proposed project, no vibration impacts would occur during operation of the proposed project. The same is expected to hold true for other projects in the vicinity of the Transit Zoning Code (SD 84A and SD 8413) area. Consequently, there would be no cumulative operational groundborne vibration impacts to any on -site or off -site receptor. This impact would be less than significant. 4.8-40 City of Santa Ana Transit Zoning Code (SD 84A and SD 848) EIR