(a) Slow moving vehicles and all trucks, buses and cars towing trailers shall use the right hand or curb lane of the roadway except when otherwise directed.
(b) Trucks, buses and other slow moving vehicles proceeding in the same direction shall not overtake and pass each other.
(c) Where the roadway is divided by a double solid line, vehicles shall not cross the dividing line unless directed by signs, delineators or by a bridge employee.