Yes, I do detest Chicago traffic. I had planned on an hour to get to my destination near Naperville (about 30 miles SW). I had not thought of taking public transportation for that leg, too. Thank you for the idea.
After I blew up that screenshot and uploaded it, I see what looks like a car rental icon now--next to the Metropolitan Lounge with a bus symbol, it looks like. It sure would be nice, if it had an information bubble on it like some of the others. I guess there is a map here for future visitors...
I am looking for additional car rental counter location info. This is not labeled on the Union Station map (like airports), and the rental car company was not much help when I called. I have been to this station many times and have never seen the car rental counters.
From the info I have found...