We're a one-car family. I ride almost exclusively; the wife mostly drives, but she often has the kids with her. We're looking to get her an electric assist bike to do some shopping around town, but frankly, she lacks the confidence to cycle more (in Charlottesville, VA -- reasonably bike friendly, but hard to get to a lot of places).
Congestion really isn't an issue -- I live 3 miles from my office -- but easy parking downtown is nice.