This provision can be both a "subjective immission" control and an "objective emission" control. Normally there are daily curfews and in some case weekend curfews. The subjective aspect is to prevent noise disturbance in the adjacent community. The objective aspect is to control the sound output of specific machines. There are four major sources of site noise: (1) direct sound from continually operating equipment such as air compressors; (2) intermittent sound from equipment such as jack hammers;(3)backup alarms; and (4) hauling equipment such as trucks. Air compressor noise is regulated by CFR 204 and backup alarms are regulated by CFR 1926. Boston, MA(Section 16–26.4) permits construction on weekdays between 7am and 6 pm. Madison, WI (Chapter 24.08) limits sound levels to 88 dB(A) at 50 Feet. Miami, FL (Section 36-6) considers the noise a noise disturbance if it occurs between 6pm and 8am during the week and any time on Sunday. Dallas, TX (Section 30-2 (9)) permits construction in residential zones from 7am to 7pm on weekdays, from 9am to 7pm on Saturdays and Holidays, and prohibits construction on Sundays. Albuquerque, New Mexico (Section 9-9-8) has a more complex control. It prohibits construction and demolition within 500 feet of noise sensitive properties (residences included) if the equipment sound control devices are less effective than the original equipment and if noise mitigation measures are not used when the levels exceed 90 dB (weighting not specified) or more than 80 dB during the day for three days.