In my family, we have one car for 4 licensed drivers. We brought up our children cycling, and now that they're older (one is a Junior in High School and the other is a Freshman in college), they have continued the good habit. I commute by bicycle to work year round, regardless of weather, unless the roads are treacherous. My commute is 8 miles.
Nowadays, if I lived in a large city with mass transit, I would combine mass transit with a nice folding bicycle. Jim Gagnepain