The driver of a vehicle intending to turn at an intersection shall do so as follows.
(Iowa Code § 321.311)
(A) Both the approach for a right turn and a right turn shall be made as close as practical to the right-hand curb or edge of the roadway.
(B) Approach for a left turn shall be made in that portion of the right half of the roadway nearest the centerline thereof and after entering the intersection the left turn shall be made so as to depart from the intersection to the right of the centerline of the roadway being entered.
(C) (1) Approach for a left turn from a two-way street into a one-way street shall be made in that portion of the right half of the roadway nearest the centerline where it enters the intersection.
(2) A left turn from a one-way street into a two-way street shall be made by passing to the right of the centerline of the street being entered upon leaving the intersection.
(1999 Code, § 64.01)