Question about interchanges on Illinois Tollways

[Lightning Strike]

SO I've come to the realization that the one thing that erks me the most about Illinois are the tollway interchanges  . There aren't any corresponding number to the interchanges, which might not be necessary for people who live in and around the Chicagoland area. However this makes it quiet difficult for me to direct people since I am more used to exits having a mileage number assigned to them. My question is, is there any specific reason why IDOT did not assign exit numbers? 

[Brandon]

It's not IDOT, it's ISTHA (Illinois State Toll Highway Authority).  In the early days, exit numbers were not viewed as needed (IDOT didn't even have them until the late 1970s, IIRC).  That has changed recently, and ISTHA has placed exit numbers on I-88 west of Aurora.  They will be placed on the rest of the tollways within a year.  As for mileage, that's easy.  ISTHA has used standard mileposting for quite some time (with their own twist if 1/2 and now 1/4 and 3/4 mileposts).

[roadman65]

I believe on the NW Tollway the milepost numbers are backwards though.  Just like several hundred miles to the east on I-90 in New York, so is it here.  It goes from 0 at O Hare International Airport to the WI Line.  Making them in both cases E to W instead of the standard W to E.

The NY Thruway is this way cause of its awkward alignment, but the NW Tollway is true E and W and partially N-S between Rockford and Wisconsin.  It should have been like normal all along.

[hobsini2]

I believe on the NW Tollway the milepost numbers are backwards though.  Just like several hundred miles to the east on I-90 in New York, so is it here.  It goes from 0 at O Hare International Airport to the WI Line.  Making them in both cases E to W instead of the standard W to E.

The NY Thruway is this way cause of its awkward alignment, but the NW Tollway is true E and W and partially N-S between Rockford and Wisconsin.  It should have been like normal all along.

That was the case with the NW Tollway up until this year. The ISTHA has changed it to start with the Wisconsin state line.  The freeway sections of I-90 in IL have always been correct increasing going West to East including the first 3 miles in IL up to Rockton Rd. With the new resigning, the reverse mileage markers are no longer an issue.