Why don't people carpool and use public transportation?

[Drolefille]

The only place I've lived with half decent public transport was St. Louis, and the metrolink there was really not useful. The stops were generally in bad neighborhoods and never actually went from those neighborhoods to places where people would work. Downtown is alright, but if you didn't need to go there, you didn't need to take the metro. They're getting a bit better, but not enough.