It looks like an open-road toll, but it's not. The signs say, "TEST ZONE NO TOLLS TAKEN".
What is the Illinois Tollway testing? They're testing for a lot of things, since the overhead grid has been there for a while.
They're testing cameras and antennas, so they can test the use of transponders from other states. They're also testing a transponder sticker tag that would attach to windshields. Long term, they're testing for the use of apps on cell phones to pay tolls.
To find out more, visit illinoistollway.com.