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�UIIM 1 _ 1 II I _ I . <br />There are two sets of noise criteria that apply to the Bristol Street <br />widening project. These include the federal noise criteria (promulgated <br />by the Federal Highway Administration (FHWAJ) and the City of Santa <br />Ana noise standards established in the Noise Element of the General <br />Plan and the City's Noise Control Ordinance. Each set of criteria uses <br />a different noise metric and a unique methodology of assess noise <br />impacts. <br />Federal Standards: The FHWA has developed a series of design noise <br />levels for various activity categories which are expressed in terms of <br />equivalent sound levels (Leq) or L10 values.' These design noise levels <br />are commonly used in federally funded projects or projects for which <br />federal review or Caltrans review is anticipated. <br />The FHWA design noise levels incorporate trade -offs between desirable <br />and feasible noise levels (recognizing that in many cases lower noise <br />exposures would result in even greater community benefits). The - <br />Federal -Aid Highway Program Manual, Volume 7, Chapter 7, Section 3 <br />(FIRM 7.73) has established design noise levels for different activity <br />categories. Residences, schools and recreation areas are in activity <br />Category B which specifies an exterior design noise level of 67 dBA .- <br />(Leq). Most commercial areas are in activity Category C with a <br />corresponding design noise level of 72 dEA (Leq). The design noise rt <br />levels are to be applied to: <br />those undeveloped lands for which development is planned <br />designed and programmed on the date of public knowledge of <br />the highway or other federally funded construction project, <br />those activities and land uses in existence on the date of public <br />knowledge of the project; and <br />those areas which have regular human use and in which a - <br />lowered noise level would be of benefit. <br />1�u values are noise levels exceeded ten percent of the time. They are <br />commonly used to express peak hour noise levels (since peak hour traffic <br />volumes are typically 10 percent of the daily traffic volume). <br />III -16 <br />75C -87 <br />