I think the point is: As long as the person is with you, they share the fuel cost. You already decided to use a car, so you're driving, but the other person is now able to split the cost with you and hitch a ride.

Unfortunately the reality of the situation is: Even with Uber / Lyft there are instances of groping and rape. Once you are in someone's car they have power over you. They don't have to stop. They can threaten to crash the car, etc. And without any vetting this is a risky move.

This can absolutely not survive without some sort of support.

While others say "people already hitchhike" the truth is yes, and there's no liable company so people get paranoid and such. This app will enable a bigger scale which causes more issues.