People (like me) often drive or ride a bus or train part of the way for their commute for a variety of reasons... in SoCal it's not uncommon for a commute to be 40-60 miles so riding a bike the entire distance is impractical. In my case there are no safe routes to ride all the way to work (freeways, narrow/busy canyon roads) so I haul my bike through the dangerous parts then ride the remaining distance to work and back.