Iowa Code Title VIII. Transportation [Chs. 306-330B] § 321.461. Trailers and towed vehicles

1. When one vehicle is towing another the drawbar or other connection shall not exceed fifteen feet from one vehicle to the other except the connection between any two vehicles transporting poles, pipe, machinery, or other objects of structural nature which cannot readily be dismembered.

2. If the towing vehicle is a motor truck and the towed vehicle is a single trailer with a single point of articulation at the hitch connection, the drawbar or other connection shall not exceed twenty-one feet. The length of the drawbar or other connection shall be measured from the centerline of the hitch assembly on the towing vehicle to the front of the body of the towed vehicle. A vehicle which has a drawbar or other connection which measures between fifteen and twenty-one feet in length shall have at least one yellow reflector visible on each vertical face of the drawbar or other connection, located near the midpoint between the towing and the towed vehicle. A vehicle which has a drawbar or other connection which measures between fifteen and twenty-one feet in length shall have affixed to the rear of the towed vehicle a sign indicating that the vehicle is a towed vehicle.