Arnold Schwarzenegger, former Governor of California poses gives a thumbs-up on a bicycle during a photo call in London, March 31, 2011. September 22 is World Car Free Day. The event promotes using mass transit, cycling and walking, and the development of communities where jobs are closer to home and shops within walking distance. Whether a show or not, many politicians and socialites have been seen riding bicycles in public to promote environmentally friendly ways of travel. [Photo/Agencies]

Former US president George W. Bush prepares to exercise by bike in Maryland, May 5, 2007. [Photo/Agencies]