It would be great if, instead of just on/off to avoid toll roads, users could customize how much money they'd be willing to spend to save a certain number of minutes.
This could be put into the UI as a slide bar—with the option to put in a manual number—that ranges from "Always Avoid" on one end (equivalent to $0/min) to "Always Permit" on the other end (equivalent to "infinite"/min).

As an example: I'm more than willing to avoid a toll if it costs more than $1 for 5-minute savings (e.g I would avoid a $1 toll if it only saved 3 min to use it), but if that $1 toll saves me more than 5 min (or $2 for 10+ min, etc.), I'd love to take the toll road instead.