I think it must depend on where you live. I'd always prefer to ride my bike to work, but with kids' schedules and my wife and I both working it's not always possible. I only ride to work 3x a week, sometimes 4.

My ride is 14 miles, takes about 45 minutes. If I have to drive I take a different route - about 8 or 9 miles, and about 12 minutes. If I lived where there's traffic and that 8 or 9 miles took an hour, I'd get rid of the car entirely - and be happy about it.