No person shall make any excavation in, or cause any damage to, any street in the City, except under the conditions and in the manner permitted in this chapter. No person shall place any article, thing or obstruction in any street, except under the conditions and in the manner permitted in this chapter, but this provision shall not be deemed to prohibit such temporary obstructions as may be incidental to the expeditious movement of articles and things to and from abutting premises or to prohibit the lawful parking of vehicles within that part of the street reserved for vehicular traffic.