A warning decal shall be attached to every truck-trailer combination, except trailers subject to section 60-6,243, having a connection device between such vehicles which is more than twelve feet in length. Such decal shall be made of red reflectorized material and contain the words:

LONG VEHICLE

PASS WITH CARE

The letters shall be of white reflectorized material and shall be not less than three inches in height.

The decal shall be affixed to the sides and rear parts of the trailer at a height of not less than forty-eight inches nor more than seventy-four inches from the ground level.