No person shall ride, drive, propel or cause to be propelled any vehicle or animal across or upon any sidewalk, except over permanently constructed driveways and except when it is necessary for any temporary purpose to drive a loaded vehicle across a sidewalk; provided, that such sidewalk area shall be substantially protected by wooden planks two inches thick, and written permission be previously obtained from the Chief of Police. Such wooden planks shall not be permitted to remain upon such sidewalk area during the hours from six p.m. to six a.m. (Ord. 155 NS § 8.3, 1967; prior code § 13-38.)