Excavation operations shall be conducted in such a manner that a minimum amount of interference or interruption of street traffic will result. Inconvenience to residents and businesses fronting on public streets shall be minimized. Suitable, adequate and sufficient barricades shall be available and used where necessary to prevent accidents involving property or persons. Barricades must be in place until all of excavator's equipment is removed from site and excavation has been backfilled and proper temporary gravel surface is in place. From sunset to sunrise, all barricades and excavations must be clearly outlined by acceptable warning lights, lanterns, flares and other devices. Police and fire departments shall be notified at least twenty four (24) hours in advance of any planned excavation requiring street closures or detours. (Prior Code § 11-391)