Iowa Code § 318.11: Billboards and signs.

1. No billboard or advertising sign or device, except a sign or device authorized by law or approved by the highway authority, shall be placed or erected upon a highway right-of-way.

2. A billboard or advertising sign, whether on public or private property, that obstructs the view of any portion of a public highway or of a railway track making the use of the traveled portion of the right-of-way dangerous is a public nuisance and shall be abated. The person responsible for the erection and maintenance of the billboard or sign may be punished as provided in chapter 657.