Publication Detail

Time Use: Workshop Report

UCD-ITS-RP-02-18

Reprint

Time use is synonymous with activity engagement; activities an individual engages in over a period of time; say, a day, can be precisely described by knowing how the individual uses time, and his time use can be reconstructed by compiling the set of activities he pursued chronologically. In this sense, time use analysis is nothing new to the field of travel behaviour analysis. In fact, activity-based analyses of travel behaviour should be examining the individual's use of time, both in home and out of home. Many so called "activity-based" analyses of travel behaviour, however, are based on travel survey data that contain information on trips and their purposes, but not on activities engaged in at home, or on multiple activities pursued at a destination. For this reason, these studies have been criticized as only paying lip service to activity-based analysis. The reason for this is obvious; data are rarely available that can be applied to a full-fledged analysis of activity and travel behaviour. Indeed it is difficult to locate a data set that contains information on activities, both in home and out of home, their locations, and attributes of the trips made to the activity locations at levels of detail needed for travel behaviour modeling.

Time use surveys and data are rather new to the field of travel behaviour analysis. While there have been a number of comparable studies across many countries, and standard categories have been proposed for activity type classification, it is only recently that travel behaviour researchers have directed their attention to time use data. In fact this conference may be the first occasion where a number of studies of travel behaviour that are based on time use data are presented. Using travel survey data in an activity-based analysis of travel behaviour involves the critical limitation that there is no information on in-home activities. Consequently no analysis can be performed on the substitution of activities between in home and out of home. This is critical because it pertains to the generation of trips; to address the issue of why people travel the way they do and gain a thorough understanding of travel behaviour, it is imperative that all activities pursued by an individual, both in home and out of home, be observed and investigated. While recent travel surveys have attempted to capture in-home activities, they are not as thorough as time use surveys in capturing activities, for both in-home and out-of-home activities. The most complete account of the individual's activity engagement can be found in time use data.
Published in Perpetual Motion: Travel Behavior Research Opportunities and Application Challenges, ed. H.S. Mahmassani, Elsevier Science Ltd., chapter 16.