321.499  “Person” defined.
  The term “person”, as used in section 321.498 shall mean:
  1.  The owner of the vehicle whether it is being used and operated personally by said owner, or by the owner’s agent.
  2.  An agent using and operating the vehicle for the agent’s principal.
  3.  Any person who is in charge of the vehicle and of the use and operation thereof with the express or implied consent of the owner.
[C31, 35, §5079-d12; C39, §5038.02; C46, 50, 54, 58, 62, 66, 71, 73, 75, 77, 79, 81, §321.499]
See also §321.1(52)