My household is 'car-lite', we have one older, high mileage beater that is used for errands/group trips.
Previously, we had two cars. The motivation was two-fold. In 2010 a household, family member suffered some severe health issues. Selling one of the cars (the one still carrying a monthly payment) became a financial imperative.
I continued to drive the remaining car for a few months, but then the introduction of using a bike came out of simple logistics. My son was scheduled for a job interview mid-morning.
If I had the car at work, he would be unable to go to the interview. I opted to ride my bike to the bus-stop.. which has since grown to full on commuting.
Over time, I've actually come to prefer using the bike.