8. Combinations of road vehicles shall consist of one of the following combinations:(1) one towing vehicle and 1 trailer;
(2) one tractor hauling 1 or 2 semi-trailers;
(3) one tractor hauling 1 semi-trailer and 1 trailer;
(4) one farm tractor hauling 2 trailers; or
(5) one tractor hauling 1, 2 or 3 motorized road vehicles or chassis of motor vehicles coupled according to the saddle-back method.