No person may cause or permit a sound level that exceeds the applicable level specified in this subtitle. No person may cause or permit a sound level from the construction, repair, or demolition of a structure or street that exceeds any applicable level set by a rule or regulation of Commissioner, except in accordance with a temporary exemption permit or as necessary to do emergency work. No person may operate a motor vehicle so as to exceed any applicable sound level set by a rule or regulation of the Commissioner. No person may use a vehicle horn except:as reasonably necessary to assure safe operation; or as an emergency warning signal. For sound levels set in this subtitle, measurements must be made with instruments calibrated by means of accepted acoustical techniques to an accuracy of plus or minus 1 dB(A). City Code, 1976/83, art. 11, §§235(a), (e), 238(a). (b), (e) Ord. 99-548