The Superintendent of Public Works may, upon
notifying the Police Department and the Fire Department, close any
street or public place or section thereof to public traffic for the
purpose of repairing, constructing or reconstructing the same. When
so closed, at the entrance to said closed portions, signs shall be
posted indicating that the street is closed and that passing is forbidden.
No person shall drive or cause to be propelled any vehicle over any
street or portion thereof so closed when appropriately marked.