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In order to meet the General Plan noise standards, the following noise reduction measures would need to be incorporated into the project: • Install a 6-foot tall acoustically effective barrier along the west and north portion of the site. • Install windows and exterior doors with Sound Transmission Class (STC) ratings of 28 to 42, depending on floor level and occupancy of the room/area. • Provide forced air mechanical ventilation (e.g., air conditioning) in all residential units so that windows and doors may be closed at the discretion of the occupants to control noise. Staff notes that the above measures would address train engine/wheel noise but exclude mitigation for train horns, which may require mitigations that are infeasible and/or unacceptable from a design and neighborhood impact standpoint (e.g., tall sound walls). The General Plan indicates the City Council will evaluate the requirement to achieve the General Plan noise standards in the Downtown on a case-by-case basis. Staff believes that a condition of approval requiring disclosure of frequent train whistle noise is sufficient. Noise Impacts on Adjacent Properties The development of the property will generate added urban noise, such as traffic and landscape maintenance activities. However, noise levels are not expected to change substantially from those currently experienced in the area because overall activity levels at the site would be modest. Ambient noise levels could decrease for some of the adjacent properties due to the shielding of traffic noise by the proposed buildings. Short-term construction noise would be generated during any new construction on this site. The City normally allows construction hours from 8:00 a.m. to 5:00 p.m., Monday through Friday, with Saturday construction allowed if nearby residents are unlikely to be impacted by construction noise or activities. Since there are existing residences directly adjacent to the proposed project site, staff is recommending that Saturday construction not be allowed. Staff is recommending a condition that would allow the Director of Community Development to approve earlier construction "start times" or later "stop times" only for specific construction activities (e.g., concrete pouring) if it can be demonstrated to the satisfaction of the Director of Community Development that the expanded construction hours are necessary (e.g., the concrete foundations need to be poured early due to weather conditions). Construction equipment would be required to meet Department of Motor Vehicles (DMV) noise standards and be equipped with muffling devices. Vibration The General Plan requires that the project demonstrate that it would be compatible with the vibration impact criteria established by the Federal Transit Administration (FTA). The buildings may need to have spread foundation footings or post/beam foundations, resulting in a raised first floor with a "crawl" space underneath the floor, instead of slab on-grade foundations in order to meet the FTA criteria. PUD-118, 4791 Augustine Street Planning Commission Page 21 of 25