Conducting a household travel survey with GPS: reports on a pilot study

In late 2008, a team of consultants was put under contract by the Ohio Department of Transportation to conduct a GPS survey of households in the Greater Cincinnati area of southwest Ohio, northwest Kentucky, and southeast Indiana. A pilot survey was conducted in March-April 2009, and this paper reports on the outcome of that pilot study. In this paper, the procedures for recruitment of households, delivery and collection of GPS devices, and the rates of completion of the survey are described. A prompted recall survey, using a web-based survey is also described. The purpose of the web-based prompted recall survey is to collect sufficient data to allow improvement and addition to existing processing software, so that the GPS data will provide sufficient information to allow travel demand models to be estimated, as well as informing various policy issues. Preliminary results from the pilot survey indicate some issues with completion of the GPS task and also with the prompted recall survey. These issues have suggested the use of variable incentives in the main survey to improve overall response levels and significant changes to the prompted recall survey, which have been implemented. Statistics are also provided on some of the sociodemographic characteristics of the pilot sample, and this is compared to Census data for the Greater Cincinnati area. However, it was not expected or intended that the pilot sample would be a representative sample of the population. Preliminary analysis of the data collected by GPS indicates a substantially higher rate of trip-making than has been measured in the past, using conventional diary methods. While this latter result was expected, the magnitude of the increase is larger than expected.