I work in public transit so I want to highlight 
public transit's contribution to saving our planet.  An individual switching to public transit can reduce his or her daily carbon emissions by 20 pounds; that’s more than 4,800 pounds a year.  This is more than the combined carbon emissions reduction that comes from using energy-efficient light bulbs, adjusting thermostats, weatherizing one’s home, and replacing an older refrigerator with a high efficient refrigerator.  Canon G10, 1/200 sec at f/8.0, ISO 200, 12mm equivalent focal length/