An Analysis of Variability of Travel Behavior within One-Week Period based on GPS
In 1997 the Department of Transportation carried out a one-week study in Lexington, Kentucky in which the cars of 100 households were equipped with GPS and in-car computers. Every stop was logged by the GPS receiver and the purpose of the stop was recorded at real time on an in-car computer. The final report of the study gave descriptions of travel behavior but performed little analysis on the data so collected. Provided a CD-Rom data record of all the transactions from DOT, we proposed to address questions such as (1) How does the week period influence different types of people's travel activities in a general way?; (2) How does the week period influence the variation of people's travel choices on different days of week?; and (3) to what extent is the automatic-device-collected data more accurate than the data collected by using traditional methods?
In this paper, two physical measurements of trips (duration and frequency) are analyzed to differentiate people's activity patterns among the days in a week period in terms of types of activities pursued. MONOVA analysis is applied first to illustrate the day-to-day activity variability across the week. Then time series analysis is used to further reveal the temporal characteristics of the trip series. Accompanying these, the advantages and disadvantages of using GPS-integrated devices as a means of collecting travel activity data are analyzed.