Pendyala, Ram M., Huichun Zhao, Ryuichi Kitamura (1989) Telecommuting and Travel Demand: An Activity-Based Impact Assessment. Institute of Transportation Studies, University of California, Davis, Research Report UCD-ITS-RR-89-02
The secondary objective of the analysis is to identify differences in travel characteristics between those who are scheduled to telecommute, and those who will participate in the Pilot Project as "control group" members. The participants of the Pilot Project consist of state employees who expressed interest in telecommuting in response to the solicitation by the Project coordinator. These employees were all requested to fill out an extensive questionnaire prepared by JALA Associates, the principal consultant for the Pilot Project, to measure "success factors" and evaluate each employee's suitability for telecommuting. Based on the recommendation by JALA Associates and evaluations of the supervisors, final assignments were made by the participating state agencies as to who would telecommute and who would participate as control group members.
Because of this self-selection and assignment process, it is possible that the telecommuters and control group members possess different socio-economic characteristics and mobility orientations. The intent of the analysis is to measure the difference between the two groups at the outset of the study and assure that subsequent assessment will be free of sample selection biases.
The panel survey serves as the primary information source for this travel demand impact assessment. A three-day travel log is used in each wave of the survey. Respondents are requested to record the purpose, mode, beginning and ending time, and other salient attributes of all trips they make on the survey days. The household members of the project participants who are 16 years old and over are also requested to fill out the diary.
The first wave of survey was administered by the state agencies and the questionnaire was distributed in conjunction with telecommuting training sessions. Because of this, the survey dates were scattered over a 6-month period from January through June, 1988, with most diaries filled out in January and June. The subsequent waves of survey will be administered in the same manner and, to the extent possible, will be conducted in the same period of the year as the first wave for each respondent. The quality of the responses in the first-wave survey and the revisions of the survey instruments are documented in a separate report.
Comprised of volunteer participants of the Telecommuting Pilot Project, the sample of this panel survey is not likely to be representative of the population of the State of California. It is therefore important to compare this sample and a state-wide sample in order to infer how employees interested in telecommuting differ in their travel characteristics from the statewide averages.
As an initial attempt, sample statistics from this survey are compared to corresponding statewide figures obtained from the 1976–1980 Statewide Travel Survey. The comparison contained in this report, however, is heavily affected by the difference in sample composition: the sample of this study consists of state employees and their household members who are at least 16 years old, while the statewide statistics are representative of the state population. Further comparisons will be made when statewide statistics comparable to the present sample are obtained from the Division of Transportation Planning.
The rest of this report is organized as follows. The next section offers an overview of the data files used in the analysis of this study. Section 3 presents a comparison of trip characteristics among household members (project participants, their spouses, and their children). This is followed by the comparison between home telecommuters and control group members presented in Section 4. Section 5 describes car ownership and travel mode choice characteristics. Section 6 examines the significance of interrelationship between origin base, destination base, person category, and project participation status (telecommuters versus control group members). Finally, Section 7 offers a summary of the findings and conclusions that may be drawn on the basis of the analysis of the first wave survey results.