Traffic levels increased when the existing downstream US 36 bridge over the Mississippi River was closed to make room for the new I - 72 bridge .
It was built before the extension of Interstate 72 ( I - 72 ) west into Hannibal , Missouri .
Traffic levels increased when the existing downstream US 36 bridge over the Mississippi River was closed to make room for the new I - 72     bridge .
It was built before the extension of Interstate 72 ( I - 72 ) west into Hannibal , Missouri .