On private property, toll regulation according to a market seems fair enough under a free-enterprise system.
On public property, toll roads are always unfair unless the toll rate is virtually insignificant to all potential users. Any other explanation does appear deceptive, whether intentional or not.
Therefore it is usually just destructively extractive for the average users to fund roads on public property exclusively by tolls alone.
When the public tolling entity is under the jurisdiction of electable officials in a working democracy, the proper response is for a disruptive candidate to campaign on a platform of eliminating toll roads altogether. With public support this could include public purchase of private toll roads according to eminent domain if a price affordable to the citizens can not be negotiated.
Other things being equal, this type candidate should be able to prevail in cases where toll rates are particularly significant to the citizens in general.
Assuming of course free enough enterprise and democracy working well enough . . .