Project Description

In the United States and Europe, increasing attention is being paid to the measurement of long-distance travel behaviour. Such measurement poses special problems which are not encountered in the measurement of daily mobility in urban areas, which has been the focus of attention of most previous household travel surveys. Because long-distance travel is a relatively rare event, a major issue has been the selection of the period of observation. Unlike daily mobility surveys, where the most common survey period is a single 24-hour period, long-distance travel surveys have used survey periods from several weeks to several months. However, selection of too short a period means that many respondents have no long-distance trips to report, while selection of too long a period means that frequent long-distance travellers have many trips to report, some of which occurred a long time before the conduct of the survey. This results in problems or recall or, in the extreme, problems of non-reported trips or even non-response. As a result, many surveys have used survey periods of 2 to 3 months. However, this method can result in under-reporting of trips from infrequent travellers, who are recorded as non-travellers, and possible under-reporting from frequent travellers because of the recall and response problems mentioned above.

In response to the above-mentioned problems, an alternative survey design was proposed by TUTI which seeks to obtain information from all respondents about the most recent long-distance trip they have made, irrespective of when that trip was made. For frequent travellers that trip may have occurred today, while for infrequent travellers the trip may have occurred months or even years ago. Each respondent reports the details of only their most recent trip. In this way, trip information is obtained from all respondents, while limiting the response burden for the frequent long-distance travellers. The project considers how the data obtained from this survey design can be used to obtain unbiased estimates of long-distance trip rates.