I used to live in Chicago (near west suburbs) and visit relatives in South Bend/Elkhart. If I was pinching pennies I took I94/2/20. But the if weather was iffy, or I was in a rush, I tended to take the tollway (including the Chicago Skyway). Traffic on the toll route was usually light except for the Dan Rayan. The toll-less route included the Borman Expy south of Hammond, which was usually heavy high speed traffic.
http://posttrib.suntimes.com/news/16931937-418/new-study-says-indiana-toll-road-lease-bad-deal.html#.U8nTGVTGEVkThis article debates whether the 75 lease of the ITR was a good deal for the state or not. Note that the claim that it was a bad deal depends on the assumption that the original public corporation could have raised tolls at the same rate as the concessionaire is.