Pain and Joy of a Panel Survey on Transport Studies

[EN] Over ten years ago, it was established that the most frequent reason that motivates a panel survey on transport studies is theevaluation of a change in the transportation system, or a specific transportation-planning project, especially when the projectinvolves novel elements. From a statistical viewpoint, a panel survey has the definite advantage to offer more accurate estimatesof changes than cross-sectional surveys for the same sample size. Observing travel patterns of individuals and households overseveral consecutive days, has offered insights into activity scheduling and travel planning. Variability in travel patterns hasimportant policy implications as well, but how much effort is worth to design a panel survey?To evaluate the effects of the transport policies introduced in Madrid during the last five years, a ‘short-long’ panel survey wasbuilt, based on a sample of a Madrid-worker subpopulation most affected by those recent changes in transport policy. The paperdescribes both the design and construction of the panel based on GPS technology, and presents some results based on an analysisof its two waves; for example, it registered an increment of public transport use and walking trips in 10%. The panel overcomesthe known attrition problem thanks to providing incentives, maintaining contact, using the same interviewer for the samerespondents, and conducting face-to-face interviews.