1. The sound attenuation plan shall include a noise analysis of the property that details the projected Freeway noise levels based upon the most current projected traffic volumes available from the Maricopa Association of Governments. The time period for the projected traffic volumes and traffic characteristics shall be a minimum of fifteen (15) years from the date of the submittal of the sound attenuation plan, unless otherwise approved by the City Engineer, or his or her designee. In the event that the design and development of the projected Freeway is not at a stage for which a noise analysis is reasonably feasible, then no such noise analysis shall be required, but the sound attenuation plan shall obligate the property owner to construct or otherwise provide for a sound barrier wall of a minimum of eight (8) feet in height, or an acceptable equivalent, and install landscape treatments, subject to the approval of the Zoning Administrator, or his or her designee.

2. The sound attenuation plan shall include the proposed attenuation measures needed to reasonably predict that the projected exterior noise levels on the property at ground level shall not exceed the (L_eq) sixty-seven (67) dBA noise level. For the purposes of this Overlay District, the noise measurement method used by the Arizona Department of Transportation (ADOT) and the Federal Highway Administration (FHWA) will be used. In addition to any proposed attenuation measures, a sound attenuation plan may also identify who, in place of the property owner, may be responsible for specific measures, the timing for installing the specific attenuation measures, and describe or provide for proposed alternative means of compliance as to any specific attenuation measures as may be approved by the City Engineer, or his or her designee.

3. The sound attenuation plan shall include a certification by a qualified transportation noise analyst as to the projected exterior noise levels on the site and that the sound attenuation measures will meet the (L_eq) sixty-seven (67) dBA noise level.

1. The sound attenuation plan shall also include measures needed to reasonably predict that the projected interior noise levels for each dwelling unit or building unit or building determined to have a noise sensitive use shall achieve a maximum interior noise level of (L_eq) forty-five (45) dBA. In order to comply with this maximum noise level, a minimum of R18 exterior wall assembly, a minimum of R30 roof/ceiling assembly, dual-glazed windows and solid wood, and foam-filled fiberglass or metal doors to the exterior shall be required of new buildings or dwelling units. As an alternative, a certification by an architect or engineer to achieve a maximum interior noise level of (L_eq) forty-five (45) dBA at the time of final construction may be submitted. The sound attenuation standards within this Overlay District shall not apply to accessory buildings used on a property with the primary building. (Am. Ord. 23-1589, passed 9-25-23)