Iowa Code § 321.6: Reciprocal enforcement — patrol beats.

There shall be reciprocal cooperation between the members of the department, the state department of public safety and local authorities in the enforcing of local and state traffic laws and in making inspections, although this section shall not be construed to give the state department of public safety any right to establish regular patrol beats inside municipal limits unless requested for a special occasion or emergency by the mayor of such city or the sheriff of the county.