You have all the curves because you are climbing a mountain to get to and down from Jerome. According to Google Maps it is only six minutes longer to go the I-40, I-17, AZ-30 route though it is 30 miles farther and much easier.
From the Mountain Directory West: Going north on 89A (towards Jerome from Prescott/Chino Valley) you will encounter 4½ miles of 6-7 percent grades with 15-20 MPH curves and then 2 miles of 4 percent grades to the top coming down you would come through Jerome with some very narrow streets and an extremely sharp curve and a short section of 10-12 percent grades and then 3½ miles of 6 percent grades with sharp curves going down to Cottonwood.