If you were ever curious how new interchanges on Illinois toll roads are funded (and I am), you can find out here as the Illinois State Toll Highway Authority (ISTHA) thinks of changing its regulations:

The agency traditionally funds half the costs of interchanges, but it may provide more money if it appears revenues will exceed 50 percent of projections or if communities indicate that the location is near a major regional road or truck route.

Other considerations would be if towns can offer right-of-way land or agree to finance the project and be reimbursed by the tollway.

Another proposal would be a “corridor approach.” This could mean when a new interchange is built with tolls that are higher than other nearby ones, the agency may evaluate and increase those adjacent rates…

Some other revisions include stipulations that all future requests for interchanges must come from government agencies and requiring more financial information and payback schedules.

I had no idea this is how things work but I am not surprised. Having studied the early years of some of the Illinois toll roads, particularly I-294, I-88, and I-90, it is remarkable to me how few full interchanges were built originally. For example, I-88 only had a few full interchanges, meaning that motorists could get on or off the tollway going any direction, between the Cook County line and Aurora. Since then, things have changed as the population further west of Chicago has increased. These changes included a new full Winfield Road interchange in the 1990s (which helped spur the growth of the Cantera property which has become quite important to Warrenville), an added full interchange at Route 59 (originally it only had two ramps), and a new interchange at Eola Road to help handle the growth in the Aurora area. Of course, not all of the interchanges have been improved: exits like Route 53 are still limited. Additionally, if you drive on other toll roads like the Indiana, Ohio, and Pennsylvania Toll Roads/Turnpikes, the exits are quite infrequent as it would cost a lot more money to build interchanges where the population may not support it.