A travel survey (or travel diary or travel behavior inventory) is a survey of individual travel behavior. Most surveys collect information about an individual (socio-economic, demographic, etc.), their household (size, structure, relationships), and a diary of their journeys on a given day (their start and end location, start and end time, mode of travel, accompaniment and purpose of travel).
Major travel surveys are conducted in metropolitan areas typically once a decade. Some regions, notably metropolitan Seattle, Washington conduct a panel survey, which interviews the same people year after year, to see how their particular behavior evolves over time.