I found out, that of you ommit to MANUALLY add Vignette/Toll pass/HOV pass, your navigation will be put into "Avoid highways" mode. It is a bit frustrating for all who travel a lot abroad to manually add highway passes/Vignettes for each and every highway portion we intend to drive.
My suggestion is Waze should INFORM you for needed Vignette, and you should be able to either IGNORE this (still navigating higways) or to simply (one -click) ADD needed vignette to list of passes you own. That way it would be unser-friendly. For now, when process is manual and you have gozillion of vignettes to chose from, it is very time consuming and for me a deal-breaker to use this app at all.