Abstract
Stated choice experiments are used regularly as part of the evaluation of major transport infrastructure investments, and their design can have an important effect on the accuracy of demand forecasts. Research in the field of behavioral economics has shown that format details can significantly influence how people respond to questions. The increasing ubiquity of the Internet and smartphones has produced rapid changes in survey data collection methods and has implications for stated choice experiment formats. The foregoing trends suggest that there may be opportunities to improve the stated choice formats in common use. However, it will be difficult to improve these formats without systematic, controlled experiments. Four existing publications reporting full-scale controlled comparisons of alternative formats for stated choice exercises were found, and this study presents another such experiment. Timelines are a graphical way of presenting travel time components, similar to a stacked bar chart. The use of timelines was tested as part of an Internet-based stated choice survey of car drivers in Lima, Peru. The questionnaire included a route choice exercise and a mode choice exercise. The respondents were assigned randomly to one of two formats: the timeline format and a text-only format. The timeline and the text-only choice models are similar for both choice exercises. There are indications that the timeline format makes complex choices easier. The time to choose was significantly lower with the timeline format in the mode choice exercise, and the timeline format produced significant constants for the new modes, unlike the text-only format.
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