Trucks,
semitrailers, and trailers, except utility trailers, without rear
fenders, attached to a commercial motor vehicle registered for over
twenty-four thousand (20,000) pounds shall be equipped with mud flaps
for the rear wheels when operated on the public highways of this State.
If mud flaps are used, they shall be wide enough to cover the full
tread width of the tire or tires being protected; shall be so installed
that they extend from the underside of the vehicle body in a vertical
plane behind the rear wheels to within eight (8) inches of the ground;
and shall be constructed of a rigid material or a flexible material
which is of a sufficiently rigid character to provide adequate protection
when the vehicle is in motion. No provisions of this Section shall
apply to a motor vehicle in transit and in process of delivery equipped
with temporary mud flaps, to farm implements, or to any vehicle which
is not required to be registered.