Complex sentence: 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.
Split into simpler sentences: 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. It would then span across the state to the South Omaha Bridge where US 275 crossed the Missouri River.