No person engaged in making repairs or erection of buildings or structures, streets, pavements, or sidewalks shall obstruct the street unnecessarily or at all except when actually engaged in such work, and then only by leaving fee and ample and easy passway and passage for vehicles and pedestrians; provided, when necessary, and with the written consent of the Mayor or City Engineer, specifying the time, place, and manner of such obstruction; and subject to the provisions of this chapter as to barriers and lights, obstructions may be made.
('60 Code, § 14-8) Penalty, see § 91.99