Three national sources of data provide information on the journey to work:
1. The Census Bureau administers the decennial census "long form," which contains several questions on the journey to work, to approximately 1 in 6 households (about 15 million in 1990). The census provides the most detailed demographic and geographic information on commuting behavior. The decennial census includes the Census Transportation Planning Package, a set of special tabulations on commuting for state, county, county subdivision, places over 2,500, and traffic analysis zones.
2. The American Housing Survey (AHS) contains many of the same commuting questions as the decennial census. Every odd year, the Census Bureau conducts the AHS for the Department of Housing and Urban Development with a sample of about 53,000 households nationwide.
3. The Federal Highway Administration conducts the Nationwide Personal Transportation Survey (NPTS) approximately every 5 years. (The NPTS is now part of the National Household Travel Survey.) In 1995, the NPTS surveyed a national sample of about 42,000 households. Respondents recorded all trips, including work trips, made on a single day in a trip diary. The diary provided data on work trips (if the respondents went to work on that day) and their relationship to other activities and trips that day. Demographic and geographic data were collected for all respondents.