No person shall ride, drive, propel, or cause to be propelled any vehicle or animal across or upon any sidewalk excepting over permanently constructed driveways and excepting when it is necessary for any temporary purpose to drive a loaded vehicle across a sidewalk; provided further, that the sidewalk area shall be substantially protected by wooden planks two inches thick, and written permission shall be previously obtained from the director of public works. 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. 530(part), 1988).