Walking and bicycling are minor components of passenger travel in terms of total miles traveled or trips taken. According to the 2001 National Household Travel Survey (NHTS), walking accounted for 0.7 percent of person-miles of daily1 (mostly local) travel (26.2 billion miles), and bicycling accounted for 0.2 percent (6.2 billion miles) in 2001. By trips, walking accounted for 9 percent (35.3 billion trips) and bicycling, 1 percent (3.5 billion trips) of daily trips  (figure 2-4).
However, the shares of walking and bicycling vary by distance traveled. Of all trips under a mile, for instance, one-quarter are taken on foot and another 2 percent are made by bicycle (figure 2-5). These shares drop off sharply as trip distance increases.
Trip purpose is another element of a person’s decision whether or not to walk or use a bicycle. Trips to visit friends and relatives and for other social and recreational purposes (e.g., to go to the gym, attend a movie, go to a bar, visit a park, or visit a library) are often made on foot, especially shorter trips (figure 2-6). For instance, 39 percent to 43 percent of these trips of a mile or less are accomplished by walking. However, people are much less likely to walk a mile or less to see a doctor or dentist (7 percent) or to shop (13 percent). The share of walking trips dips below its overall share (9 percent) at about 3 miles. Bicycling as a share of all trips by distance and purpose shows the same overall tendency as does walking, although its share of trips for social and recreational purposes between 3.1 miles and 4.0 miles in length is twice (2 percent) its share of all trips..
1. U.S. Department of Transportation, Bureau of Transportation Statistics, Federal Highway Administration, 2001 National Household Travel Survey, January 2004 dataset, available at http://www.nhts.ornl.gov/2001/index.shtml, as of June 2004.
1 See Section 5, “Variables Influencing Traveling Behavior” for a discussion about the definition of daily travel.