I unfortunately live in an area where cars are a necessity.
Transit is not an option. Though the nearest bus stop is 0.6 miles from my house, I would have to take three buses to cover that 3.3 miles, which would take 1 hour and 10 min.
While it is only 3.3 miles from my home to my office, and there are bike lanes much of the way, I have seen too many motorists use the bike lanes to pass motorists on the right. Also, the distance is too short to bother changing into cycling gear, but far enough that riding here in my work clothes would mean arriving very sweaty - especially in the summer heat.
Also, in the nine years we've lived here, the area has blown up, so I am no longer comfortable riding my bike near my house after work. So, I end up doing all my mid-week training on the rollers. On most weekends, I can get out of the house without a problem, except for in the fall, when one of the local colleges have a noon kick off.