Upon those streets or portions of streets which have been signed or marked for angle parking, no person shall park or stand a vehicle other than at an angle to the curb or edge of the roadway or within 12 inches thereof as indicated by such signs and markings.

No part of any vehicle, or the load thereon, when parked within a diagonal parking district, shall extend into the roadway more than a distance of 16 feet when measured at right angles to the adjacent curb or edge of roadway.