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An operational measure of individual accessibility for use in the study of travel-activity patterns
Book Reviews
of travel for the specific park. In contrast, when travel distance becomes great, the relationship becomes positive. When the spatial structure variables are included in a recreation travel model, the results of this study indicate that the model improves not only in terms of goodness-of-fit but also stability.
63
efficient pricing of private parking and public roadways would augment information-based strategies in improving the effectiveness of regional ridesharing programs.
Multiple stops and retail choice: Their intraurban variations. lakahashi, Shigeo, Ph.D. UniversiThe influence of organizational structure on mode choice for the journey from home to work: Three essays on urban transportation analysis. Ferguson, Erik Tillman, Ph.D. Universify of Southern California, 1988. Chairman:
Peter Gordon (Copies available exclusively from Micrographics Department, Doheny Library, USC, Los Angeles, CA 90089-0182, U.S.A.) The influence of organizational structure on mode choice for the journey from home to work is analyzed using the 1977 and 1983 Nationwide Personal Transportation Studies, a 1985 survey of Southern California employers, and a 1986 survey of Los Angeles employers and employees. Organizational structure is defined in terms of the size, composition and internal policies of firms, households, and carpools. The formation of carpools is a product of urban form, pricing, transaction, and information costs. As organizational size increases, the likelihood of carpooling tends to increase. This is a function of economies of scale in the formation of carpools, related to firm size through internal information and external (spatial) transaction cost advantages. As the homogeneity of organizational composition increases, the likelihood of carpooling tends to increase. The more similar organizational members are in terms of location and travel behavioral needs and requirements, the more likely they will be to carpool. Organizational policies may influence the formation of carpools positively or negatively, depending on the manner in which specific policies mediate relations between organizational members and potential carpool partners. Carpools are dynamic, in that they tend to be more unstable over time than other modes of travel. Factors affecting short-term mode stability are different from those affecting long-term mode stability. Programs and policies with significant long-term effects are not always revealed as such in short-term project evaluations. Carpool potential is limited by the spatial and temporal distribution of activities within urban areas, but can be increased through policies which acknowledge and incorporate the influence of organizational structure on mode choice decisions. Coordination of regional, local, public, and private aspects of employer-based ridesharing programs is essential for the promotion of efficient levels of carpooling on a systemwide basis. Coordinated strategies should focus on the reduction of information and transaction costs associated with the formation of carpools through a combination of personalized and computerized matching services. More
ty of Kansas, 1988. 157 pp. Advisor: Valerie Preston
Order Number DA8903 165 On shopping trips, multiple stops are popular and seem to influence the choice of shopping destinations. With little empirical evidence, it remains unclear how consumers’ efforts to combine stops on a trip affect their decisions about places to visit. The study confirmed empirically that consumers assigned substantial weight to the utility of possible future stops when choosing the next stop. A retail choice model does not represent consumers’ decisions properly when the effects of multiple stops are not considered. Inclusion of multiple stops is important to improve retail choice models, yet additional factors also need to be considered to improve the models. The extent to which multiple stops and the friction of distance affected retail choices varied according to consumers’ residential location, income, and family structure. Multiple stops are an especially important determinant of retail choices for consumers in households with few shopping opportunities nearby home, higher incomes, and children. Most of these consumers are less sensitive to travel time than others who have ample shopping opportunities near home, higher incomes, and children. Segmentation of consumers is recommended to improve the performance of a retail choice model. From a long-term perspective, a fundamental understanding of the decision-making process that underlies retail choices is necessary to develop a model that explains intraurban variations in retail choices.
An operational measure of individual accessibility for use in the study of travel-activity patterns. Villoria, Olegario Guerrero, Jr., Ph.D. The Ohio State University, 1989. 175 pp. Advisors: Zoltan A. Nemeth and Mark R. McCord Order Number DA891 37 10
Spatial, temporal, and transportation constraints affect the formation of travel-activity patterns by limiting individual urban accessibility. To enable the study of the relationships between these constraints and travel-activity patterns, it is necessary to have an operational measure of individual accessibility. However, current measures of accessibility are deficient in their representation of the collective and inter-related influence of these constraints on travel-activity be-
64
Book Reviews
havior. Hence, the objective of this research is to suggest and empirically demonstrate the use of a more adequate measure of individual accessibility in the study of travel-activity patterns. This measure is called time-space reach (TSR) and is based on Hagerstrand’s time-space prisms concept. The rationale for the use of TSR, and its conceptual and quantitative formulation, were based on fundamental tenets and ideas from activity-based travel behavior research and time-space geography. The empirical demonstration utilized data from a one-day travel-activity diary for 5,126 urban residents of Davao City (Philippines). Individual TSR values were calculated and statistically analyzed in relation to available variables such as location, occupation, vehicle ownership, and income. The results of this analysis were found to be reasonable. The TSR values were then used to assess the importance of accessibility as a determinant of travel-activity patterns. First, cluster analysis was performed to classify individual daily travel-activity patterns into a relatively small number of distinct clusters. The analysis yielded 20 clusters which were further aggregated into 5 groups based on similarity in activities undertaken. Finally, the 5-cluster scheme was used as the dependent variable in performing linear logit analysis, where TAR and 8 commonly hypothesized determinants (i.e. occupation, gender, lifecycle stage, age, vehicle ownership, income, possession of driver’s license, and household location) are the independent variables. The results indicate that TAR is at least as important as the known principal determinants of travel-activity patterns (i.e. occupation, gender and age). This research has shown conceptually and empirically that TAR is an operational measure of individual accessibility that can be used in studying the influence of spatial, temporal, and transportation constraints on travel-activity patterns.
A study of the Los Angeles Coastal Transportation Corridor Specific Plan. Blankson, Charles Codman Taylor, Ph.D. University of California, Los Angeles, 1989. 238 pp. Chair: Martin Wachs Order Number DA9007 108 The Coastal Transportation Corridor Specific Plan (Ordinance Number 160, 394) was enacted by the Los Angeles City Council on October 22, 1985, to deal with traffic from new projects planned for the cities of Venice, Mar Vista, Palms, Westchester and Playa de1 Rey. The objective of the study was to evaluate the trip reduction goal of the ordinance. To do this, we selected a sample of 8 buildings with 117 firms and 1216 employees. The sample was made up of 3 buildings with 44 firms and 620 employees subject to the ordinance, and 5 buildings with 73 firms and 596 employees not subject to the ordinance. The results of the study indicate that developers subject to the ordinance are more likely to provide preferential parking in their projects for ridesharers, bicycle racks
for employees, and transportation coordinators. Employers in buildings affected by the ordinance offer free parking at work to a much smaller proportion of their employees than employers in buildings not affected by the ordinance. Among those who pay to park at work, employees in buildings subject to the ordinance pay higher fees than those in buildings not subject to the ordinance. The facilities and services provided by developers and employers subject to the ordinance seem to have affected, somewhat, the commuting patterns of their employees. Twice as many workers in buildings subject to the ordinance rideshare to work, although they constitute only a small proportion of the work force. Slightly fewer employees in the buildings subject to the ordinance drive alone to work than their colleagues in buildings not subject to the ordinance. Despite these findings, the conclusion of the study is that the ordinance has not and may not be able to reduce trip generation. The study is important because many cities, including other areas of Los Angeles, are in the process of enacting similar programs. Furthermore, the City of Los Angeles is on the verge of revising the Coastal Corridor Ordinance. Evaluative studies such as this one provide a data base for use in evaluating measures which may or may not be used in future ordinances.
Toward a comprehensive understanding of rideshare promotion: The use of evaluation research. Horan, Thomas Anthony, Ph.D. Claremont Graduate School,
1988. 160 pp. Chairman:
Robert
Allen Keith Order Number DA8900970 With traffic congestion becoming a serious problem in many metropolitan areas, rideshare promotion is increasingly being viewed as an important congestion reduction strategy. Since the oil embargo of 19731974, the primary governmental mechanism for promoting ridesharing has been through rideshare agencies (RSAs). These RSAs work mainly with local employers to promote ridesharing to employees. Recent evidence suggests that RSAs could be more effective if they worked to develop comprehensive employer rideshare programs, rather than focusing predominantly on the provision of matchlists to employees. This study, drawing upon the “theory-driven” approach suggested by Chen and Rossi (1983), delineated a program model for a more comprehensive rideshare promotional effort, and then executed an evaluation based upon several hypothesized relationships. Entitled “The Client Development Model,” this model specified the expected influence of rideshare program implementation-as well as the influence of exogenous employer and employee characteristics - on employee rideshare behavior. An RSA study located in Orange County, California served as the setting for the study. Multistage sampling procedures were used to select a systematic sample of both
of travel for the specific park. In contrast, when travel distance becomes great, the relationship becomes positive. When the spatial structure variables are included in a recreation travel model, the results of this study indicate that the model improves not only in terms of goodness-of-fit but also stability.
63
efficient pricing of private parking and public roadways would augment information-based strategies in improving the effectiveness of regional ridesharing programs.
Multiple stops and retail choice: Their intraurban variations. lakahashi, Shigeo, Ph.D. UniversiThe influence of organizational structure on mode choice for the journey from home to work: Three essays on urban transportation analysis. Ferguson, Erik Tillman, Ph.D. Universify of Southern California, 1988. Chairman:
Peter Gordon (Copies available exclusively from Micrographics Department, Doheny Library, USC, Los Angeles, CA 90089-0182, U.S.A.) The influence of organizational structure on mode choice for the journey from home to work is analyzed using the 1977 and 1983 Nationwide Personal Transportation Studies, a 1985 survey of Southern California employers, and a 1986 survey of Los Angeles employers and employees. Organizational structure is defined in terms of the size, composition and internal policies of firms, households, and carpools. The formation of carpools is a product of urban form, pricing, transaction, and information costs. As organizational size increases, the likelihood of carpooling tends to increase. This is a function of economies of scale in the formation of carpools, related to firm size through internal information and external (spatial) transaction cost advantages. As the homogeneity of organizational composition increases, the likelihood of carpooling tends to increase. The more similar organizational members are in terms of location and travel behavioral needs and requirements, the more likely they will be to carpool. Organizational policies may influence the formation of carpools positively or negatively, depending on the manner in which specific policies mediate relations between organizational members and potential carpool partners. Carpools are dynamic, in that they tend to be more unstable over time than other modes of travel. Factors affecting short-term mode stability are different from those affecting long-term mode stability. Programs and policies with significant long-term effects are not always revealed as such in short-term project evaluations. Carpool potential is limited by the spatial and temporal distribution of activities within urban areas, but can be increased through policies which acknowledge and incorporate the influence of organizational structure on mode choice decisions. Coordination of regional, local, public, and private aspects of employer-based ridesharing programs is essential for the promotion of efficient levels of carpooling on a systemwide basis. Coordinated strategies should focus on the reduction of information and transaction costs associated with the formation of carpools through a combination of personalized and computerized matching services. More
ty of Kansas, 1988. 157 pp. Advisor: Valerie Preston
Order Number DA8903 165 On shopping trips, multiple stops are popular and seem to influence the choice of shopping destinations. With little empirical evidence, it remains unclear how consumers’ efforts to combine stops on a trip affect their decisions about places to visit. The study confirmed empirically that consumers assigned substantial weight to the utility of possible future stops when choosing the next stop. A retail choice model does not represent consumers’ decisions properly when the effects of multiple stops are not considered. Inclusion of multiple stops is important to improve retail choice models, yet additional factors also need to be considered to improve the models. The extent to which multiple stops and the friction of distance affected retail choices varied according to consumers’ residential location, income, and family structure. Multiple stops are an especially important determinant of retail choices for consumers in households with few shopping opportunities nearby home, higher incomes, and children. Most of these consumers are less sensitive to travel time than others who have ample shopping opportunities near home, higher incomes, and children. Segmentation of consumers is recommended to improve the performance of a retail choice model. From a long-term perspective, a fundamental understanding of the decision-making process that underlies retail choices is necessary to develop a model that explains intraurban variations in retail choices.
An operational measure of individual accessibility for use in the study of travel-activity patterns. Villoria, Olegario Guerrero, Jr., Ph.D. The Ohio State University, 1989. 175 pp. Advisors: Zoltan A. Nemeth and Mark R. McCord Order Number DA891 37 10
Spatial, temporal, and transportation constraints affect the formation of travel-activity patterns by limiting individual urban accessibility. To enable the study of the relationships between these constraints and travel-activity patterns, it is necessary to have an operational measure of individual accessibility. However, current measures of accessibility are deficient in their representation of the collective and inter-related influence of these constraints on travel-activity be-
64
Book Reviews
havior. Hence, the objective of this research is to suggest and empirically demonstrate the use of a more adequate measure of individual accessibility in the study of travel-activity patterns. This measure is called time-space reach (TSR) and is based on Hagerstrand’s time-space prisms concept. The rationale for the use of TSR, and its conceptual and quantitative formulation, were based on fundamental tenets and ideas from activity-based travel behavior research and time-space geography. The empirical demonstration utilized data from a one-day travel-activity diary for 5,126 urban residents of Davao City (Philippines). Individual TSR values were calculated and statistically analyzed in relation to available variables such as location, occupation, vehicle ownership, and income. The results of this analysis were found to be reasonable. The TSR values were then used to assess the importance of accessibility as a determinant of travel-activity patterns. First, cluster analysis was performed to classify individual daily travel-activity patterns into a relatively small number of distinct clusters. The analysis yielded 20 clusters which were further aggregated into 5 groups based on similarity in activities undertaken. Finally, the 5-cluster scheme was used as the dependent variable in performing linear logit analysis, where TAR and 8 commonly hypothesized determinants (i.e. occupation, gender, lifecycle stage, age, vehicle ownership, income, possession of driver’s license, and household location) are the independent variables. The results indicate that TAR is at least as important as the known principal determinants of travel-activity patterns (i.e. occupation, gender and age). This research has shown conceptually and empirically that TAR is an operational measure of individual accessibility that can be used in studying the influence of spatial, temporal, and transportation constraints on travel-activity patterns.
A study of the Los Angeles Coastal Transportation Corridor Specific Plan. Blankson, Charles Codman Taylor, Ph.D. University of California, Los Angeles, 1989. 238 pp. Chair: Martin Wachs Order Number DA9007 108 The Coastal Transportation Corridor Specific Plan (Ordinance Number 160, 394) was enacted by the Los Angeles City Council on October 22, 1985, to deal with traffic from new projects planned for the cities of Venice, Mar Vista, Palms, Westchester and Playa de1 Rey. The objective of the study was to evaluate the trip reduction goal of the ordinance. To do this, we selected a sample of 8 buildings with 117 firms and 1216 employees. The sample was made up of 3 buildings with 44 firms and 620 employees subject to the ordinance, and 5 buildings with 73 firms and 596 employees not subject to the ordinance. The results of the study indicate that developers subject to the ordinance are more likely to provide preferential parking in their projects for ridesharers, bicycle racks
for employees, and transportation coordinators. Employers in buildings affected by the ordinance offer free parking at work to a much smaller proportion of their employees than employers in buildings not affected by the ordinance. Among those who pay to park at work, employees in buildings subject to the ordinance pay higher fees than those in buildings not subject to the ordinance. The facilities and services provided by developers and employers subject to the ordinance seem to have affected, somewhat, the commuting patterns of their employees. Twice as many workers in buildings subject to the ordinance rideshare to work, although they constitute only a small proportion of the work force. Slightly fewer employees in the buildings subject to the ordinance drive alone to work than their colleagues in buildings not subject to the ordinance. Despite these findings, the conclusion of the study is that the ordinance has not and may not be able to reduce trip generation. The study is important because many cities, including other areas of Los Angeles, are in the process of enacting similar programs. Furthermore, the City of Los Angeles is on the verge of revising the Coastal Corridor Ordinance. Evaluative studies such as this one provide a data base for use in evaluating measures which may or may not be used in future ordinances.
Toward a comprehensive understanding of rideshare promotion: The use of evaluation research. Horan, Thomas Anthony, Ph.D. Claremont Graduate School,
1988. 160 pp. Chairman:
Robert
Allen Keith Order Number DA8900970 With traffic congestion becoming a serious problem in many metropolitan areas, rideshare promotion is increasingly being viewed as an important congestion reduction strategy. Since the oil embargo of 19731974, the primary governmental mechanism for promoting ridesharing has been through rideshare agencies (RSAs). These RSAs work mainly with local employers to promote ridesharing to employees. Recent evidence suggests that RSAs could be more effective if they worked to develop comprehensive employer rideshare programs, rather than focusing predominantly on the provision of matchlists to employees. This study, drawing upon the “theory-driven” approach suggested by Chen and Rossi (1983), delineated a program model for a more comprehensive rideshare promotional effort, and then executed an evaluation based upon several hypothesized relationships. Entitled “The Client Development Model,” this model specified the expected influence of rideshare program implementation-as well as the influence of exogenous employer and employee characteristics - on employee rideshare behavior. An RSA study located in Orange County, California served as the setting for the study. Multistage sampling procedures were used to select a systematic sample of both