Ilan Salomon

How derived is the demand for travel? Some conceptual and measurement considerations

This paper contests the conventional wisdom that travel is a derived demand, at least as an absolute. Rather, we suggest that under some circumstances, travel is desired for its own sake. We discuss the phenomenon of undirected travel – cases in which travel is not a byproduct of the activity but itself constitutes the activity. The same reasons why people enjoy undirected travel (a sense of speed, motion, control, enjoyment of beauty) may motivate them to undertake excess travel even in the context of mandatory or maintenance trips. One characteristic of undirected travel is that the destination is ancillary to the travel rather than the converse which is usually assumed. We argue that the destination may be to some degree ancillary more often tan is realized. Measuring a positive affinity for travel is complex: in self-reports of attitudes toward travel, respondents are likely to confound their utility for the activities conducted at the destination, and for activities conducted while traveling, with their utility for traveling itself. Despite this measurement challenge, preliminary empirical results from a study of more than 1900 residents of the San Francisco Bay Area provide suggestive evidence for a positive utility for travel, and for a desired travel time budget (TTB). The issues raised here have clear policy implications: the way people will react to policies intended to reduce vehicle travel will depend in part on the relative weights they assign to the three components of a utility for travel. Improving out forecasts of travel behavior may require viewing travel literally as a “good†as well as a “bad†(disutility).

Telecommunications and travel relationships: a review

Abstract A large body of research on the interactions of telecommunications and transportation has emerged in recent years, an outcome of the pace of development in electronics technology. Three types of interactions are noted: substitution, complementarity and enhancement, by order of their popularity. The paper reviews the knowledge on the relationships between the two systems through the analysis of applications of telecommunications technology for remote work, teleconferencing, teleservices, mobile communications and electronic mail transfer. It points to the importance of assessing future modifications of travel rather than focusing on the promises of substitution. The review also assesses the methods applied in this area and suggests further research, in view of some conceptual and practical issues.

Modeling the desire to telecommute: The importance of attitudinal factors in behavioral models

This paper begins to operationalize a previously published conceptual model of the individual decision to telecommute. Using survey data from 628 employees of the City of San Diego, hypothesized drives to telecommute and constraints on/facilitators of telecommuting are measured. A binary logit model of the preference to telecommute from home is estimated, having a p2 of 0.68. The explanatory variables include attitudinal and factual information. Factor analysis is performed on two groups of attitudinal questions, identifying a total of 17 (oblique) factors which can be classified as drives and constraints. Additional measures are created from other data in the survey, usually objective sociodemographic characteristics. Variables representing at least four of the five hypothesized drives (work, family, independence/leisure, and travel) are significant in the final model. Variables from four of the ten groups of constraints (job suitability, social/professional and household interaction concerns, and a perceived benefit of commuting) are significant, primarily representing internal rather than external constraints. The results clearly demonstrate the importance of attitudinal measures over sociodemographic ones, as the same demographic characteristics (such as the presence of children, commute time) will have different effects on preference for different people.

Modeling the choice of telecommuting: setting the context

In this paper a conceptual model of the individual decision to telecommute is presented. Key elements of that decision, including constraints, facilitators, and drives, are defined and the relationships among them described. The major types of constraints (if negative) or facilitators (if positive) include external factors related to awareness, the organization, and the job, and internal psychosocial factors. The major types of drives are work, family, leisure, ideology, and travel. It is argued that the absence of constraints is a necessary but not sufficient condition for telecommuting to be adopted by an individual. The presence of one or more drives, assumed to be associated with some dissatisfaction, is necessary to activate the search for a solution to that dissatisfaction. The choice set contains those alternative solutions perceived to be feasible by the individual. It may or may not contain telecommuting (depending on whether all constraints are nonbinding or not), and probably contains other alternatives having nothing to do with telecommuting. Each alternative is evaluated in terms of how effectively it satisfies the drive, and the individuals attitudes toward it. The alternative (or bundle of alternatives) which maximizes individual utility becomes the preferred behavioral pattern. However, short-term constraints may prevent the preferred behavior from being chosen. The process is a dynamic one, in which previous choices affect attitudes and constraints and alter drives. Work directed by the authors is under way to operationalize the conceptual model.

The impact of gender, occupation, and presence of children on telecommuting motivations and constraints

Accurate forecasts of the adoption and impacts of telecommuting depend on an understanding of what motivates individuals to adopt telecommuting and what constraints prevent them from doing so, since these motivations and constraints offer insight into who is likely to telecommute under what circumstances. Telecommuting motivations and constraints are likely to differ by various segments of society. In this study, we analyze differences in these variables due to gender, occupation, and presence of children for 583 employees of the City of San Diego. Numerous differences are identified, which can be used to inform policies (public or organizational) intended to support telecommuting. Most broadly, women on average rated the advantages of telecommuting more highly than men – both overall and within each occupation group. Women were more likely than men to have family, personal benefits, and stress reduction as potential motivations for telecommuting, and more likely to possess the constraints of supervisor unwillingness, risk aversion, and concern about lack of visibility to management. Clerical workers were more likely than managers or professionals to see the family, personal, and office stress-reduction benefits of telecommuting as important, whereas managers and professionals were more likely to cite getting more work done as the most important advantage of telecommuting. Constraints present more strongly for clerical workers than for other occupations included misunderstanding, supervisor unwillingness, job unsuitability, risk aversion, and (together with professional workers) perceived reduced social interaction. Constraints operating more strongly for professional workers included fear of household distractions, reduced social and (together with managers) professional interaction, the need for discipline, and lack of visibility to management. Key constraints present for managers included reduced professional interaction and household distractions. Lack of awareness, cost, and lack of technology or other resources did not differ significantly by gender or occupation. Respondents with children rated the stress reduction and family benefits of telecommuting more highly than did those with no children at home. Those with children were more likely than those without children to be concerned about the lack of visibility to management, and (especially managers) were more likely to cite household distractions as a constraint.

MODELING THE CHOICE OF TELECOMMUTING: 3. IDENTIFYING THE CHOICE SET AND ESTIMATING BINARY CHOICE MODELS FOR TECHNOLOGY-BASED ALTERNATIVES

In previous papers in this series we have presented a conceptual model of the individual decision to telecommute and explored relationships among constraints, preference, and choice. In a related paper we developed a binary model of the preference for home-based telecommuting. Noting that there is a wide gap between preferring to telecommute (88% of the sample) and actually telecommuting (13%), in this paper we develop binary logit models of telecommuting adoption. Two approaches to dealing with constraints are compared: incorporating them directly into the utility function, and using them to define the choice set. Models using the first approach appear to be statistically superior in this analysis, explaining 63–64% of the information in the data. Variables significant to choice include those relating to work and travel drives, and awareness, manager support, job suitability, technology, and discipline constraints. The best model was used to analyze the impact of relaxing three key constraints on the 355 people in the sample for whom telecommuting was previously identified to be a preferred impossible alternative (PIA). When unawareness, lack of manager support, and job unsuitability constraints are relaxed, 28% of the people in the PIA category would be expected to adopt telecommuting. The importance of behavioral models to forecast telecommuting adoption accurately is emphasized and is suggested to have wider implications for predicting technology-based activity changes.

Telecommuting: The employee's perspective☆

Abstract Available telecommunication technology enables the substitution of commuting by “telecommuting”, or working at home, for a wide range of white collar occupations. Research on the potential of this phenomenon along with some ongoing experiments point at an array of social and personal benefits that may be realized by this working arrangement. An assessment of the possible implications of work-at-home on the individual employee indicate that the burden on him or her may be greater than the benefits accrued and, therefore, the journey to work may be a more desirable act than traditionally perceived by transportation planners. This paper focuses on two aspects of the work-at-home arrangement. Previous research on the sociology of work as well as preliminary empirical results indicate that 1) social interaction at work and 2) the need to separate home and work roles are important elements for the individual worker. The fact that work-at-home will affect these attributes, is likely to discourage wide-scale transition to this arrangement, despite the availability of the technology. Most research published to date on the subject is qualitative in nature, as only little empirical evidence is available. The objective of this paper is to stress, based on a wide literature review, the need for a thorough behavioral evaluation of the available technology to provide a sound basis for decision making on implementation of the technology.

Technological change and social forecasting : the case of telecommuting as a travel substitute

Telecommuting, along with other telecommunications services, is often suggested to be a solution to congestion-related transportation problems. Forecasts of telecommuting and its impacts have typically overestimated the adoption of this arrangement. The paper reviews the problems of forecasting a complex solution to social problems. It critically assesses the wide range of forecasting approaches applied to telecommuting and the reasons for the upwards bias. The appeal of the concept, combined with various interests are among the reasons for the optimistic forecasts. Methodologically, forecasts of telecommuting tend to emphasize technological change while underestimating the social implications which determine the adoption of such technologies. A choice theory is suggested as an alternative approach which can address issues related to human behavior in the context of technological change. The explanatory power of choice models is demonstrated and suggested for future analysis of technologies which entail extensive adaptation for adopters and institutions.

MODELING THE CHOICE OF TELECOMMUTING: 2. A CASE OF THE PREFERRED IMPOSSIBLE ALTERNATIVE

A conceptual model of the choice to telecommute was advanced in an earlier paper. In this paper we present empirical data from a nonrepresentative sample of 628 City of San Diego employees on key variables and relationships in that model. The relationships among possibility, preference, and choice are examined. A key finding is the existence of a large group of people (57% of the sample) for whom telecommuting is a preferred impossible alternative. Dichotomous and continuous constraints are distinguished, and three dichotomous constraints are defined. ‘Lack of awareness’ is active for 4%, ‘job unsuitability’ for 44%, and ‘manager disapproval’ for 51% of the sample. For 68% of the sample, at least one of these constraints is active. Even among those for whom none of the dichotomous constraints is in force, most people do not choose telecommuting because of the presence of active continuous constraints. For only 11% of the entire sample, telecommuting is possible, preferred, and chosen. The potential impacts of self-selection bias are estimated, and sampling bias is qualitatively assessed. This analysis provides a crude but useful estimate of the potential of telecommuting in the population, and more specifically, the relative share of potential telecommuters who are prevented by key dichotomous constraints from choosing that option.

A FRAMEWORK FOR STUDYING TELESHOPPING VERSUS STORE SHOPPING

Abstract Transportation and geography studies of shopping behavior focus on destinatiion choice assuming a trip had to be made. New telecommunications technologies enable home-based “teleshopping” to substitute for store shopping. This paper develops a framework for studying the choice between modes of shopping. Shopping activity is defined as information acquisition that precedes purchasing. But, shopping seems to fulfill some psychological and recreational functions in addition to obtaining information. An integration of perspectives from different disciplines results in a conceptual structure which forms a basis for empirical studies of the impact of telecommunications technologies of human travel and activity patterns.