No person shall drive on a public highway any motor vehicle registered as a truck if it has been modified by alteration of its altitude from the ground to the extent that its bumpers, measured to any point on the lower edge of the main horizontal bumper bar, exclusive of any bumper guards, do not fall within the limits specified herein for its gross vehicle weight rating category. The front bumper height of trucks whose gross vehicle weight ratings are 4,500 pounds or less shall be no less than 14 inches and no more than 28 inches, and their rear bumper height shall be no less than 14 inches and no more than 28 inches. The front bumper height of trucks whose gross vehicle weight ratings are 4,501 pounds to 7,500 pounds shall be no less than 14 inches and no more than 29 inches, and their rear bumper height shall be no less than 14 inches and no more than 30 inches. The front bumper height of trucks whose gross vehicle weight ratings are 7,501 pounds to 15,000 pounds shall be no less than 14 inches and no more than 30 inches, and their rear bumper height shall be no less than 14 inches and no more than 31 inches. Bumper height limitations contained in this section shall not apply to trucks with gross vehicle weight ratings in excess of 15,000 pounds. For the purpose of this section, "truck" includes pickup and panel trucks, and "gross vehicle weight ratings" means manufacturer's gross vehicle weight ratings established for that vehicle as indicated by a number, plate, sticker, decal, or other device affixed to the vehicle by its manufacturer.