Comparative experimental application of alternative travel diaries in Cape Town and Dar es Salaam

Abstract

Paper presented at the 28th Annual Southern African Transport Conference 6 - 9 July 2009 "Sustainable Transport", CSIR International Convention Centre, Pretoria, South Africa.

Internationally, travel diaries of various forms have served as the principal means of collecting revealed preference travel data. Household interview travel survey experiences in African cities,however, have demonstrated that the collection of travel diary data is problematic for both respondents and interviewers. This paper reports on the development of a travel diary instrument for use in a planned 24-hour recall home interview survey in Cape Town, Dar es Salaam and Nairobi. As part of the development of this survey instrument an experiment was undertaken to assess the appropriateness and feasibility of different travel diary forms. In other parts of the world travel diaries have taken three main forms: trip-based, activity-based and place-based diaries. Variations of these three basic diary forms include: the recording of trips in either tabular or sequential question format; the prospective or retrospective request for respondent recall; and the use of memory joggers. The paper describes the impact of alternative travel diary forms on respondent burden, trip and trip stage recall rates, interviewer cognition and item recording or nonresponse errors, and respondent cognition and item recording errors. On the basis of the experiment findings, it is concluded that place-based diaries in sequential question format, with associated memory joggers, are likely to yield highest rates of trip recall and lowest rates of measurement error and item non-response in city contexts with respondent populations similar in socio-demographic nature to those in Cape Town and Dar es Salaam.