Tolls: who pays?

Today I took a trip where I asked the driver to take a toll road. The toll was not on the route that the driver was planning to take based on his Waze directions, which showed a completely different route. The driver was very accommodating and said that it was no problem. I asked if he pays the toll or if Uber covers the toll and it gets passed on to me and he didn’t know. He makes a phone call and speaks to someone.

As we approach the exit for the toll road he now says he doesn’t feel comfortable taking it because he will be charged an administrative fee for not having an EZPass (he shows me a past statement on his phone with the $12 fee). I told him I would include in the tip an amount to cover the $3 toll and the $12 administrative fee, but that he was free to decide what to do.

He decides to take the toll road and when I arrive I give him a $25 tip on the $17 trip.

Here’s my question: how should these situations be handled?

Is Uber going to somehow become aware of the toll and charge it to me? Are drivers not allowed to deviate from the scheduled directions and take a toll road? If a driver does have an EZPass (or doesn’t but takes the toll road anyway) do they have to pay it out of pocket? If so, does Uber reimburse them or is this tip reimbursement the solution? Should I assume that tolls are off limits for Uber rides?

Thanks.