text: "BOGOTA, Colombia... millions of Colombians hiked, biked, skated or took buses to work during a car-free day yesterday, leaving the streets o fthis capital city eerily devoid of traffic jams." This excerpt from the article explains some of the advantages of not using a car. All of them sound joyful. Hiking, Biking, Skating and no traffic jams? This sounds like a field day in the city. What could go wrong with all of these delightful activites goin on?