My wife and I share a single car in Salt Lake City and have done so in other places, included Washington DC and semi-rural West Virginia. This setup is ideal, because we can coordinate our use of the car and combine that with biking/walking and public transportation. We also have a 2 year-old son who goes to pre-school every day and has to get dropped off an picked up by car. Sharing w/i a couple or family is a really good way to reduce car usage but retain the benefits of having a car. I'm definitely a proponent of reduced usage combined with biking/walking and public transportation.