Stated choice surveys have been used in many countries all over the worldas an important tool to assess the Value Of Travel time. Such surveys generally collect information about the travel behaviour as well as about a recently experienced trip and socio-economic characteristics of the respondents. The core of the survey questionnaires consists of a series of choicesets in which the alternatives are characterized by at least two attributes, i.e. trip duration and monetary cost, mostly compared to those of somerecently experienced reference trip. The value of travel time is commonlyassessed by analysing all answers independently, with a multinomial logitmodel based on the premises of Random Utility Maximization theory. Many travel behaviour analysts found that a considerable share of the respondents to such stated choice surveys systematically selected those alternativeswith the 'best score' on one attribute only. Their opinions differ on howto cope with this so-called 'strong lexicographic answering'. This paper compares the individual responses to the 1988 and 1997 Dutch national Value Of Travel time surveys following the premises of Extended Prospect theory. This implies that the choice/answering sequences of the individual respondents rather than their separate answers are treated as the basic unit of analysis, and presumes the co-occurrence of survey population segments that apply different choice behaviour strategies and different attribute valuation approaches. The paper demonstrates that the strong lexicographic answers should better be included in the analysis. It also shows that the commonly followed MNL analyses of individual choice decisions underestimatethe value of travel time compared to an approach that presumes intrapersonal consistency in the answering of the stated choice questions. For the covering abstract see ITRD E135582.
Abstract