When any street in the city has been closed or barred from entrance for the purpose of constructing, repairing, paving, sewering or otherwise improving the street, either by the city or by the Board of Park Commissioners or their authorized employees or contractors, no person shall take down or disturb any barriers that may have been erected or drive over such streets without the permission of the Street Department of the city or the Board of Park Commissioners, their authorized representatives or the contractor engaged in doing such work.
('71 Code, § 549.11) Penalty, see § 101.99