Another big example is written my Andrew Selsky, and he states, "In a program that's set to spread to other countries, millions of Colombians hiked, biked, skated, or too buses to work during a car-free day yesterday, leaving the streets of [Bogota, Colombia] eerily devoid of traffic jams." Densely populated cities and highways are extremey dangerous, both for cars that may get into accidents and for the pedestrians that may be present.