A Comparative Analysis of GPS-Based and Travel Survey-based Data

This paper examines the driver demographics, driver travel characteristics, and driver adherence to survey protocol considerations that impact the likelihood of under-reporting in a household travel survey. The research considers both the likelihood of vehicle driver trip under-reporting as well as the level of vehicle driver trip under-reporting using a joint binary choice-ordered response discrete model. The empirical analysis uses the Global Positioning System (GPS)-equipped sample of households from the 2004 Kansas City Household Travel Survey who also provided travel diary information. The empirical results provide important insights regarding under-reporting tendencies in household travel surveys. In particular, young adults less than 30 years of age, men, individuals with less than high school education, unemployed individuals, individuals working in clerical and manufacturing professions, workers employed at residential land-uses, individuals who make many trips, travel long distances and trip-chain, and respondents who fail to use a travel diary to log their travel before telephone retrieval of their patterns are associated with higher under-reporting. Also, the underlying factors influencing whether an individual under-reports or not are different from the factors impacting the level of under-reporting.