No person shall park a vehicle upon any roadway for the principal
purpose of:
A. Displaying such vehicle for sale.
B. Greasing or repairing such vehicle, except necessitated by an emergency.
No person shall park any trailer, semitrailer or tractor upon
any public street while such trailer, semitractor or tractor is detached
from its component unit, except when such trailer or semitrailer is
in a continual process of loading or unloading goods, wares or merchandise.