Landing at O'Hare Chicago in a few weeks and traveling to Duluth (MN) via a stopover in Madison (WI). We will be traveling on the I90 which I see is a toll. or part toll road. I have looked at the relevent website but find it slightly confusing. How much of this route is toll? Do you have to leave the road to pay tolls? Do you need a lot of coins or are the toll booths manned?