Every person who cuts any pavement or makes any excavation or obstruction in any of the public thoroughfares or public grounds within the city, or so near such public thoroughfares and public grounds as to be dangerous to those traveling upon such streets and grounds, shall establish and maintain sufficient substantial barricades about such cutting or excavation or obstruction to warn the public and prevent users of the sidewalks and public thoroughfares from being damaged because thereof. During the nighttime, such person shall, in addition to such barricades and warning signs, maintain a sufficient number of red lights and/or torches to effectively warn the users of the sidewalks and public thoroughfares of the existence of danger. (Prior Code § 9-102.)