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D. A substantial temporary or periodic increase in ambient noise levels in the project vicinity above levels existing without project. Less than Significant Impact Implementation of the proposed project would result in short- term construction related noise impacts. The construction- related short-term noise levels would be higher than the existing noise levels in the project area, but would no longer occur once construction of the project is complete. Two types of short-term noise impacts would occur during the construction of the proposed project. First, the transport of workers and import of construction materials to the site would incrementally increase noise levels along local access roads. However, the volume of traffic generated by the construction operations would be minimal to add measurably to the existing noise levels along major access routes. Therefore, even though there could be a relatively high single event noise exposure potential associated with passing trucks, the increase in ambient noise levels would be less than 1 dBA when averaged over a 24-hour period. The second type of short-term noise impact is related to noise generated at the site during construction operations. Typically, the estimated construction noise level is governed primarily by the highest noise producing pieces of equipment. Table N-4 lists typical construction equipment noise levels based on a distance of 50-feet between the equipment and a noise receptor. TABLE N-4 NOISE LEVELS GENERATED BY TYPICAL CONSTRUCTION SOUIPMENT ype of Equipment Range of Sound Levels Measured (dBA at 50 feet) Suggested Sound Levels for Analysis (dBA at 50 feet) Pile Drivers, 12,000 to 18,000 ft-lb/below surface 81 to 96 93 Rock Drills 83 to 99 96 Jack Hammers 75 to 85 82 Pneumatic Tools 78 to 88 85 Pumps 68 to 80 77 Dozers 85 to 90 88 Tractor 77 to 82 80 Front-End Loaders 86 to 90 86 Hydraulic Backhoe 81 to 90 86 24 3~~5~$