Iowa Code § 462A.34: Authorized emergency vessels.

Upon approach of an authorized emergency vessel displaying a blue light or flashing blue light, the operator of every other vessel shall stop and yield the right-of-way until the authorized vessel has passed. The provisions of this section shall not relieve the operator of an authorized emergency vessel from the duty to operate the vessel with due regard for the safety of all persons using the waters of this state, nor shall the provisions relieve the operator of any such vessel from liability from the operator’s negligence.