A critical appraisal of the use of simple time-money trade-offs for appraisal value of travel time measures

Stated choice surveys have established themselves as the preferred approach for value of travel time elicitation with the help of choice models. However, major differences exist in the approach used across regions and contexts. In Europe (particularly Northern Europe), value of travel time is often estimated in large national studies, which continue to rely extensively on simple time-money trade-offs. On the other hand, studies in Australia and South America in particular tend to have a more local focus and follow the notion that more complex setups are preferable. The European studies however are also those where the results are actually used in cost–benefit analysis and data from European studies have formed a testbed for many advanced model specifications. The present paper aims to provide a critical appraisal of the use of simple time-money trade-offs, drawing from our experience in recent European studies. We highlight a number of issues, in terms of differences in valuations across formats as well as a lack of clarity on how respondents actually interpret travel time in these simple time-money trade-offs.