[RobertClark]

Sharing a car would certainly be a good way to share the costs of a car, provided that everybody abided by the agreement on how to split the costs.

This has been done for several decades, although not formally. They used to call them 'neighborhood cars'. I remember hearing the term many times when I was a teenager. They would purchase a car, splitting the payments or up front cost among 5 to 10 houses in the neighborhood and then set a useage agreement. Needless to say, it usually never ended well.

[Jonty30]

I suspect such shared deals rarely do work out well. It’s hard, when you’re paying part of the bill to not want to be the main guy who uses it.