Rental Cars and Toll Plazas

Another thing I noticed today was while driving the Illinois Tollway, it occurred to me that there are a lot of exit ramps that:

• Require exact change
• Have no attendant on-duty

So how are you supposed to pay the toll if, say, you're a tourist who has no idea in advance that you're going to need 80¢ here and 35¢ there? The Illinois Tollway page has this to say:

Failure to pay tolls will result in a Notice of Toll Evasion, where the toll plus a $20 fine is levied. Those who do not follow the due process outlined in the Notice could eventually face loss of license plate or driver's license through the Secretary of State's office. Video Surveillance cameras are located at all plazas to record toll violators.

Now, riddle me this:

Why haven't the tollway agencies and their "pass" programs (IPass, E-ZPass, etc.) worked together with rental car agencies so that people renting cars don't have to worry about tolls? Why couldn't I have a rental car that has an IPass box of some sort permanently attached and then, at the end of my rental, Hertz asked the IPass folks "How much has this car's tag been charged since the time he rented the car?" and simply add that amount to my rental bill?

You could even offer the option to disable the in-car IPass if you wanted, for instance for people who are renting a car, but who have their own IPass they would rather use (perhaps to take advantage of a lower-cost commuter rate-plan, or because they have a special "free access" pass like the one retired Thruway people get).

IPass would get their cut of more tolls, rental agencies' customers would be happier (and also, rental car companies would have less hassle to go through trying to track down renters of cars which were used in toll-evasion), and the tollways would likely have fewer offenders and thus also get increased revenue.

It seems to me that this would be a perfect synergy between the different organizations to get maximum value.