almost always a schedule problem. With 5 kids at home, my wife and I need to plan out the "how to get the kids home". She is usually good about letting me try to ride to and from work, but I have been known to ride home from work to pick up a child one mile from my work 5 min later. Great gas savings to justify the bike purchase. I also may have meetings I cant get to early enough and wouldn't look good in cycling bibs. This happens to me about once a week. The days I drive I make that my resupply clothes and lunch, then take home the laundry and tupperware. I usually get in 80-100 miles a week.