Prior approval for the use of public streets, sidewalks or alleys for any of the purposes indicated in Section 15.40.010 of this chapter shall be obtained from the traffic engineer. The traffic engineer shall enforce the provisions of this code pertaining to temporary use of public property and to the maintenance of walkways and barricades. The traffic engineer may prohibit the use of any or all of the portions of streets, sidewalks, or alleys permitted to be used by this code when, in his or her opinion, undue traffic hazards or congestion may be created by such use. The traffic engineer may waive the requirements of sidewalk protection if he or she permits the closing of the sidewalk to pedestrian traffic. (Prior code § 9.08.371)