Use of Special Survey Materials. The empirical results from this study indicate that an
important predictor of trip under-reporting is the extent to which a respondent travels. Those who travel
more have a higher propensity to under-report trips. This empirically supports the findings of prior
studies, most of which related the increased travel to heavier respondent burden (and thus suggested
missed trips were the respondent’s way of ending the survey interview early). While the relationship
between respondent burden and trip under-reporting is well accepted, there is another component to this
relationship that should be considered – the design of the travel log.