Iowa Code § 516D.5
A claim against an authorized driver resulting from damage to a rental vehicle, loss due to theft of a rental vehicle, or damages resulting from the loss of use of a rental vehicle, must be reasonably and rationally related to the actual loss incurred. A rental company shall mitigate damages where possible and shall not assert or collect any claim for physical damage which exceeds the actual cost of the repair, including all discounts or price reductions. Administrative fees shall be limited to the reasonable administrative costs associated with processing the damage claim. A claim made for loss of use shall not exceed the daily rental rate stated in the customer's contract, excluding optional charges, multiplied by the total of the estimated time for replacement and the estimated time for repair, divided by eight.
Iowa Code § 516D.5
91 Acts, ch 204, §5