 The proposed highway was to run from Illinois Route 80 near Port Byron , Illinois , which ran along the eastern bank of the Mississippi River , over a new bridge into Iowa , to the South Omaha Bridge where US 275 crossed the Missouri River . The entire route was to be in close proximity to US 6 across the state . It was to be the first modern four @-@ lane highway in the state , with 12 @-@ foot @-@ wide ( 3 @.@ 7 m ) lanes and an at least 15 @-@ foot @-@ wide ( 4 @.@ 6 m ) grassy median . Sixteen interchanges were planned along the route . Most interchanges were to be located near population centers ; an option to build a seventeenth near Grinnell , if necessary , was included . Eight service areas , similar in quality to those found on the Pennsylvania and New Jersey turnpikes , were planned as well . 
