IA SF643

Prohibits the Iowa Department of Transportation and state transportation commission from pursuing interstate road designation for the segment of State Highway 5 and U.S. Highway 65 between Interstate 35 and Interstate 80 unless the federal government grants an exemption for vehicle weight and size regulations

Creates an exception allowing implements of husbandry (farm equipment) that could legally operate on the highway segment before interstate designation to continue operating on it after designation, until an alternative route is developed

Authorizes the Department of Transportation to permit farm equipment operation on the highway segment farther west beyond the intersection with U.S. Highway 69

Requires the Department of Transportation to collaborate with the Des Moines area metropolitan planning organization to conduct a study and develop an accessible alternative highway route suitable for implements of husbandry

Provisions apply to the highway segment on the effective date and continue regardless of any subsequent changes to the highway's designation by state or federal authorities