both options will be available. just like uber and taxis are available right now.

but cars will suffer the biggest change. the part for humans will be separated from the rest of the car because there won't need to be a connection between human and motor, and those human parts will be safer. if you are a big company, dealing with thousands thousands of cars daily, it will be better for repairs and cleaning the human used part in a facility specially for that purpose.

also, expect byo-metrics to be the way you can use these kind of services. iris, finger/hand print, face recognition, even dna match in the foreseeable future. say goodbye to body privacy.