I would put Indiana in the middle level. They have some good control cities, but it could be better.
For example, the Indiana Toll Road says "Chicago" and "Ohio" on every interchange sign. They could sign it as "South Bend ---> Toledo" heading eastbound and "South Bend ---> Chicago" heading westbound.
Here are some other highways that I would change the control cities to...
Interstate 65: NB- Indianapolis, Lafayette, Chicago SB- Lafayette, Indianapolis, Louisville
Interstate 69: NB- Bloomington, Indianapolis, Fort Wayne, Lansing SB- Fort Wayne, Indianapolis, Bloomington, Evansville
Interstate 70: EB- Indianapolis, Richmond, Dayton WB- Indianapolis, Terre Haute, Effingham
Interstate 74: WB- Champaign
US 31 north of Indy: NB- Kokomo, South Bend, Benton Harbor SB- Plymouth, Kokomo, Indianapolis