THIS SIGN IS NOT REAL
This sign deserves some comment. Currently, the Illinois Toll Authority does not use exit numbers on the Northwest Tollway. In fact, the mile markers start in the Chicago area and increase with westbound I-90, presumably because the Tollway is considered by the Authority to head north-south and not east-west. This is unfortunate, as it is backwards from what the mile marker posting would have been if it were a "free" road. It also defeats one purpose of milepost marking - that is, allowing motorists to determine distances before a trip and estimating travel times while travelling. That they can do if they have a map which displays exit numbers (like the Illinois State Map and Iowa State Map, unlike the Wisconsin State Map) and the exit numbering sequence follows normal standards.
Interstate 39 - by Andy Field