text: In Bogota, Columbua, there is a program that's set to spread to other countries, millions of Columbians hikes, biked, skated or took buses to work during a car-free day, leaving the streets of this capital city eerily deviod of traffic jams. "It's a good opportunity to take away stress and lower air pollution," said businessman Carlos Arturo Plaza as he rode a two-seat bicycle with his wife.