75C - PH - BRISTOL EIR FROM WARNER TO ST. ANDREW

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The FHWA noise abatement criteria establish an exterior noise level for residential uses of 67 Leq. An interior level of 52 Leq applies where: 1) no exterior activity area is identified; or 2) the exterior activities are either remote from the highway or shielded in some manner so that they will not be significantly affected by the noise {but the interior activities will). When considering interior noise levels, FHWA encourages field measurements be taken, when practicable. Otherwise, the criteria apply to private yard areas and assume that typical wood frame homes provide a 10 dB (outdoor to indoor) noise reduction with windows open and a 20 dB reduction with windows closed. Within the project corridor, exterior activity area criteria apply for all affected residential uses. Under federal noise standards, traffic noise impacts occur when the predicted noise levels approach or exceed the noise abatement criteria, or when the predicted traffic noise levels substantially exceed the existing noise levels. City Standards: The City of Santa Ana General Plan Noise Element includes a series of goals, implementation policies and implementation programs related to land use compatibility with noise. The desirable maximum noise level for residential uses ranges from 65 CNEL for low density to 70 CNEL for high density. Commercial and office uses have a desirable maximum noise level of 65 CNEL and a maximum acceptable noise level of 75 CNEL. Industrial land uses have the same maximum acceptable noise level as commercial uses (75 CNEL) but a higher desirable maximum noise level (70 CNEL), In addition to the noise compatibility guidelines specified in the Noise Element, the City has adopted a Noise Control Ordinance (August 21, 1978) which specifies maximum noise levels which can be generated at the property line of residences, churches, schools and hospitals, as well as the procedure for identifying and resolving noise violations. The amount of exterior noise that can legally be generated is 55 dBA between 7 a.m. and 10 p.m., and 50 dBA between 10 p.m. and 7 am. I i. �.. Ambient noise levels in the project area are currently affected primarily by motor vehicle noise emanating from Bristol Street. The project site is far removed from public, military, and private airports, railroads, and other significant noise generators. However, the project area is subject to the sight and sound of aircraft utilizing the John Wayne /Orange County Airport. Fifteen noise measurements were taken by Endo Engineering (Decem- ber 1986) at thirteen representative locations along Bristol Street within III -17 75C -88