National Household Travel Survey
The design was a list-assisted random digit dialing (RDD) computer-assisted telephone interviewing (CATI) survey conducted over an entire year. Travel data was collected from the civilian, non-institutional population of the United States.
This survey was designed as a list-assisted random digit dialing survey, to yield an equal
sample of households with landline telephones. The national sample was increased in 20 Add-on
areas: Phoenix AZ, Tucson AZ, California, Florida, Georgia, Iowa, Cedar Rapids IA, Indiana, North
Carolina, Piedmont Region NC, Omaha NE, New York, South Carolina, South Dakota, Tennessee, Texas,
Virginia, Vermont, Chittenden County VT, and Wisconsin. The target sample size was 25,000
completed households for the national sample.