We explore how car-sharing services like Zipcar are changing urban mobility patterns and helping people reduce or eliminate personal car ownership while maintaining flexibility for special trips. • Car sharing complements public transit with each shared vehicle taking up to 13 privately owned cars off the street • 83% of Zipcar members don't own cars, and 27% sell their cars within a year of joining • 63% of car-sharing members are regular transit riders who use cars for occasional needs • M...