Trailer Attached to Tractor Not a “Motor Vehicle”

Vicariously liability is a tort law doctrine that holds another party responsible for the acts of another.  It is closely associated with the doctrine of respondeat superior, which is often invoked to hold an employer responsible for the negligent acts of an employee acting within the scope of employment.  In this case, the plaintiff was injured when the automobile he was operating collided with a farm tractor that was pulling a trailer owned by a farm corporation.  The plaintiff tried to hold the farm corporation vicariously liable on the theory that the trailer’s attachment to the tractor caused the tractor and trailer to become a single “motor vehicle” for purposes of civil liability.  The trial court disagreed, noting that the statutory definition of “motor vehicle” did not include a trailer and that the trailer did not become a motor vehicle when attached to the tractor.  Accordingly, the trial court denied the plaintiff’s request to declaratory relief and granted summary judgment for the farm corporation.   On appeal, the court of appeals affirmed, noting that the outcome of the case turned on construction of the pertinent statutes.  While Iowa law holds an owner of a motor vehicle liable for damages caused by the negligence of the driver of the owner’s vehicle, the farm corporation didn’t own the tractor involved in the case – it only owned the trailer.  So, did the tractor and trailer become a single “motor vehicle” for purposes of the owner consent statute?  The court noted that Iowa law (Sec. 321.1(42)(a)) defines a “motor vehicle” as being self-propelled and defines a “trailer” as being a vehicle without motive power that is designed for carrying people or property and drawn by a motor vehicle with no part of its weight resting on the towing vehicle (Sec. 321.1(85)).  Those definitions are part of the owner consent statute which, the court reasoned, was enacted to make sure the owners of motor vehicles remained financially responsible for damages caused by operators to whom they entrust their vehicles.  Accordingly, the court noted that the legislature specifically did not include “trailer” in the definition of “vehicle” in the owner consent statute.  But, the legislature did include “trailer” in the definition of “motor vehicle” as part of the motor carrier statutory provisions (Sec. 325A).  That made the court’s decision easy.  The legislature had specifically not included “trailer” in the definition of “motor vehicle” for purposes of the owner consent statute, but had made the distinction in a different part of the law.  When that fact was coupled with the purpose of the owner consent statute (to protect third parties from the careless operation of motor vehicles), the court reasoned that there was no reason to extend the definition of “motor vehicle” beyond the current statutory construct and purpose – to protect third parties from the careless acts of persons in physical control of self-propelled vehicles.  Zimmer v. Vander Waal, et al, No. 9-096/08-0662, 2009 Iowa App. LEXIS 129 (Iowa Ct. App. Mar. 11, 2009).