Iowa Code § 321.161: Department to fix values and weight.

The department shall annually, and at such other times as new makes or models of motor vehicles are offered for sale or sold in this state, fix the value and weight of each of the different makes and models of motor vehicles which are sold or offered for sale within the state. The value and weight as fixed by the department shall, on 1975 and subsequent year model motor vehicles, be based on the original certification as provided in section 321.157.