He was seized off a crowded school bus Jan. 29 after authorities say the gunman shot the driver dead and took him to the bunker where he was held until Monday's rescue.

NPR: FBI: Ala. Captor Rigged Bunker, Waged 'Firefight'

And the alternative often is a traffic-slowed bus, or a crowded underground train traversing a highly walkable distance.

WSJ: Timing an Urban Stroll Isn't a Walk in the Park

On a recent day in a train station, commuter Alejandro Gonzales said that a million more people are now crowded onto the subways since Transantiago did away with many of the old bus routes.

NPR: In Chile, Commuters Sue City over Transit System