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6 levels due to the project will be less than 3 dBA on all roadways. All other roadways will experience a smaller increase in noise levels (0.8 dBA or less). Project-generated noise levels at this location (and also in adjacent residential areas) will not exceed 65 CNEL. Ail other land uses adjacent to roadways will experience traffic noise level increases due to the project of 0.8 dBA or less. Thus, the project will not have a significant noise impact on existing residential land uses. The project will not result in significant increases in the noise environment in any adjacent land uses. Future Noise Levels on the Pro~ect Site Although future traffic noise levels on the project site and in the project vicinity have been estimated to be significantly higher in the year 2010 with the project than without it, these values do not take into account the effect of topographic features or intervening structures that may change the ambient noise levels. The trees, walls, and buildings which surround the project site will in actuality reduce noise to a lesser level. This reduction is not included in these projections, as well as slightly reduced traffic volumes. Therefore, these projections represent the worst case noise levels that will actually be generated from future vehicles. Exterior Noise Levels If any outdoor sensitive land use areas are to be constructed within these noise contours, mitigation measures may be required to satisfy the city's noise criteria. Outdoor living areas are subject to the city of Santa Ana 65 CNEL exterior noise standard. Outdoor living areas can include patios, backyards, balconies, etc. As precise grading plans are not yet available, locations where mitigation may be required cannot be precisely identified. In the event that noise sensitive land uses are located within the 65 CNEL traffic noise contour, the mitigation of such noise through the construction of a noise barrier and/or proper design of the dwelling units to insulate against exterior noise is feasible. A typical perimeter barrier might be required to protect project residential areas within the project site. The barrier would need to be approximately 6 feet high. The residential portion of Phase I may be adversely affected by construction of Phase II structures, particularly the residential tower. Although grading and excavation will have been completed during Phase I, the construction of mid-rise and high-rise structures in Phase II will generate noise impacts, particularly on Phase I residents. Mechanical Equipment The long-term increases in mechanical equipment onsite will contribute to increased ambient noise levels. 16