Design of stated adaptation experiments: discussion of some issues and experiences

Stated preference experiments have become commonly used methods of data collection in transportation research and the increasing importance of individual choice processes in travel behaviour research instigates the use of stated adaptation experiments. Two complementary stated adaptation approaches can be distinguished. The first approach follows the traditional stated preference methods and focuses on the statistical analysis of the variables that affect the individual choice processes; the second approach is not based on strict rules of experimental design and is mainly descriptive in nature. Based on a detailed description of two experiments of the first type, the design and implementation of such experiments are discussed. The most important lesson from our experiences with these stated adaptation experiments is the design of the hypothetical situations: the situations should be realistic for the respondents as well as useful for statistical analyses. Although this is not an easy task, the implementation of the experiments by means of an interactive Internet-based survey is found to be very helpful: such surveys are able to dynamically collect and process personalized data that can be used to design realistic and statistically sound hypothetical situations.