 East of the I @-@ 29 split , I @-@ 80 travels northeast for the next 20 miles ( 32 km ) . It passes through eastern Council Bluffs where it serves a shopping mall . Just after the Madison Avenue exit , the speed limit increases to 65 mph ( 105 km / h ) . Exit 8 is the first of many encounters with U.S. Highway 6 ( US 6 ) . The interstate leaves Council Bluffs and speed limits rise to the rural limit of 70 mph ( 110 km / h ) . Here , I @-@ 80 roughly follows the course of Mosquito Creek past Underwood and Neola , both of which are served by interchanges . About two miles ( 3 km ) of Neola , I @-@ 80 curves to the east as it meets the eastern end of I @-@ 680 at a directional T interchange . 
