Below are links to interesting transportation websites:

Calculate Your Commute
Emissions Calculator www.travelmatters.org
Commute Cost Calculator: rideshare.511.org/calculator

Walking, Biking and Trails
Colorado Walks: www.coloradowalks.org
National Center for Biking and walking www.bikewalk.org
American Hiking Society: www.americanhiking.org
 
Carpooling
Nationwide Carpool Matching: www.erideshare.com
Carpool Etiquette: www.carpool.ca/carpool_etiquette.asp
Skier-specific carpooling: www.skicarpool.com
 
Transit
Colorado Association of Transit Agencies: www.coloradotransit.com
American Public Transit Association: www.apta.com