If user could use settings to set something like "use toll roads if it shortens the time on the road for at least XX minutes" or "use toll road if fuel economy if more then $XX". Waze gives us multiple routs from A to B, sometimes it is better to use toll road, sometimes it cuts only about 5-6 minutes from the trip (or less) - still not the reason to use toll road, too expensive for this outcome. But sometimes toll road is way better, so we don't want to forbid waze to suggest us toll-roads. I think you have all the data and tools you need to make this feature possible.
Great idea! I do this manually each day as my commute can take place on either a toll or non toll road. If my time savings on the toll road is less than 10 minutes then I take the non toll road (cost benefit analysis). If the time savings is more than 10 minutes then I'll take the toll road, since this variance suggests a lot of traffic or an accident.
I also pick up my daughter from extended care at her grade school. Time is a factor and of the essence, since I don't want to be late.