It's definitely possible; if you talk to parents who live in cities they'll generally be happy to describe how they do it.
(Raised two kids from 0 to 5y and 7y without a car. Started splitting a car about 6 months ago when we had a third child. Lots of walking, double decker stroller, bus, subway, and bike trailer.)
(Raised two kids from 0 to 5y and 7y without a car. Started splitting a car about 6 months ago when we had a third child. Lots of walking, double decker stroller, bus, subway, and bike trailer.)