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Prediction, models and data: An analysis of disaggregate choice models
Bibliographic Section
in every instance, in the public interest by the Commission; (9) entry control in all its ramifications has stifled the growth of the contract carrier industry and the individual contract carrier; (10) in recent years, the regulatory environment and Commission policies, pertaining to entry control in the motor carrier industry, is changing, from one which promoted the growth and health of existing firms and fewer firms, to one which promotes entry of a larger number of small firms, especially contract motor carriers; (11) total deregulation is not required to regulate contract motor carriers in the public interest, but changes are required to more effectively regulate contract motor carriers; and (12) the necessity for regulating contract carrier rates and services, including publication of such rate schedules, cannot be economically supported.
245
mechanisms; however, no significant positive associations with service performance were found for these concepts. In fact, internal control mechanisms generally displayed significant negative associations with service. Considering the study’s economic variables, a major finding was that vanlines display a greater sales orientation, a greater profitability, and a worse service performance record. This finding implies that the industry might face certain structural defects. since C.O.D. service deficiencies are not economically sanctioned by the market. Possible institutional arrangements are therefore presented as policy options to improve the linkage between service and financial performance and to dampen vanline sales orientation.
Demand Analysis
Household Goods Carrier Systems: Organized Control of Member Agents and Owner-Operators, Edward Anthoney Morash, 1979, UMI 7926495 (Dissertation at the University of Maryland, College Park, MD 20740). This dissertation is a study of the household goods moving industry, and in particular, a study of the control and operating practices of household goods firms. The major hypothesis tested was that those parent household moving systems which exercise greater external control over member agents and owner-operators exhibit superior service and financial performance. Several subsidiary hypotheses were concerned with the types of external and internal control and their relationships to performance. Another group of hypotheses was directed at testing the relationships between performance and a group of economic and structural variables such as firm size, sales orientation, and firm structure. The primary theoretical basis for the research questions was organizational control theory and particularly the external-internal contingency approach. The independent variables relating to control types were measured by a survey instrument. Of the 332 Class I and II household goods carriers surveyed, 202 responded for a 61 percent response rate. The performance measures were obtained from Interstate Commerce Commission data. The primary statistical approach for the analysis was multiple regression. The major findings of the study were that smaller non-agency carriers made greater use of personal control mechanisms which tended to relate positively with service performance. Moderately sized agency systems with less than 75 agents made greater use of detailed administrative or output control which also related positively to service performance measures. For the largest agency systems, the emphasis was on broad administrative or output control which showed some tendency to be related with effective service performance. Other control concepts which were characteristic of larger agency systems included the exercise of expert power,formal training mechanisms, monetary rewards, and internal control
Prediction, Models and Data: An Analysis of Disaggregate Choice Models, Youssef Dehghani-Ghotbabadi, 1980, UMI 8027598 (Dissertation at the State University of New York, Buffalo, NY 14214). In the study several issues important to travel demand analysis were studied. These included: data accuracy and its effects, model and variable specification, modal aggregation, market segmentation, tests of the IIA property, and forecasting accuracy. The comparison of observed (manually coded) and network based level-of-service attributes showed that especially the excess time components are poorly calculated by the network. However, the total travel time is approximated quite accurately by the network for car and bus modes but not for BART (rail). This was attributed to the difficulties in including access mode and station choices into the network models. Coefficients estimated with the two types of data were not numerically similar. Statistical tests showed that the modal constants were different even though the cost coefficients were different by a fourfold margin in most of the models estimated. The reason for this discrepancy was attributed to the way parking costs have been calculated and assigned to the travellers by the network. Statistical results showed that the most satisfactory specification for travel time components is to lump them together : another interesting result is that the alternative specific constants for rail modes and express bus modes’ constants were found to be valued equally. A simple method was successfully used to aggregate rail and bus modes. The resulting coefficients of corresponding variables among all the models were consistent as they were statistically equal and numerically very close. No clear cut answers were found regarding the advantages of dividing travellers into homogeneous groups. Market segmentation by household income seems to be warranted on the basis of model estimation, while market segmentation by other variables-namely, CBD-bound travellers vs others and car owership variables-did not appear necessary.
246
Bibliographic
It was found that MNL-model is robust with respect to the independence of irrelevant alternatives (HA) property and only sensitive to the aggregation of auto modes but not of bus modes.
The Effects of Personality on Recreational Travel Behavior, Gokmen Ergun, 1979, UMI8008159 (DisUniversity, Evanston, sertation at Northwestern IL 60201). The goal of this study was to investigate the effects of personality on various components of the decision process related to recreation and recreation-travel related choices. Although various components on which personality may have some effect were identified, two of these were selected for inclusion in the research. These were the individual perception process, and the individual evaluation and choice process. Before the effects of personality on two components or the decision were analyzed, it was necessary to undertake a personality inventory related to recreation and the recreation-travel environment. Although some relevant scales were found in some extant inventories, these were lacking some concepts that were directly related to recreation choices. Therefore a major personality scale-construction effort was undertaken to construct these lacking scales. This effort resulted in twelve scales, six of which were selected-by some preliminary correlational analysis-for testing the effects of personality on the recreation-related decision components. The effects of personality variables on perceptions on recreation activities were tested using multivariate multiple-regressions; seemingly-unrelated regressions; multivariate analysis of variance and covariance; and their associated test statistics. These tests showed, quite that personality affects perceptions conclusively, significantly in the hypothesized manner. The effects of personality on rhe individual evaluation and choice process-which was represented by the recreation-activity preferences-were tested by building multinomial logit activity-choice models and using the associated test statistics. Personality variables were used both as alternative-specific additive terms and as segmentation variables. Both of these methods showed that these effects were highly significant and logical.
Generalization of Demand Models for Areawide Travel Forecasting. Fong-Lieh Ou, 1980, UMI 8101011 (Dissertation at the University of Utah, Salt Lake City, UT84412) With the emphasis in recent transportation planning on the needs of fast-response methodology, efforts have been made to test the transferability of travel demand models. There is, however, little evidence that models are transferable between geographical areas. It is the purpose of this research to determine the impact of urban character such as size class, activity concen-
Section
tration, and geographical cluster on urban travel demand, and to incorporate these characters into model development. The emphasis in this study is on the development of a model generalization procedure and the generalized areawide demand models which can be applied to various urban areas. The model generalization procedure begins with parallel steps of variable selection and model structure development. and then estimates and verifies the preliminary models. Following these steps the procedure goes on to develop and validate generalized models. Chow’s test is employed to examine the model stability over time; Ott’s test is utilized to determine the statistical significance of urban character: and the generalized dummy variable approach is applied to account for possible effects of urban character on travel demand. The generalized models are designed to predict areawide trip frequency, trip length, and mode choice for non-metropolitan and metropolitan areas, and to provide estimates on total person trips, person-miles-of-travel, and person-hours-of-travel. These measures are postulated to be dependent upon the activity and transportation system variables and influenced by urban character. For non-metropolitan areas. trip frequency and trip length models are developed. The trip frequency is a function of auto ownership and household size, while the trip length is a function of population. The relationships of these two models are affected by the type of activity concentration and by geographical cluster. For metropolitan areas, demand models are developed for the trip frequency, trip length as well as mode choice. The trip frequency is related to auto ownership, household size, and population, and is affected by geographical cluster. The trip length is dependent upon population, land area, and population density, and is affected by urban size class, activity concentration, and geographical cluster. The travel by auto is explained by auto ownership and population density, the travel by transit is a function of auto ownership, population density, and population, while the travel by walk is related to auto ownership and the supply of transit service. These relationships are by and large affected by urban size class and geographical cluster. The data for the empirical estimation of the models is a nationwide sample of 1960’s. The predictive ability of the models is validated by the backward and forward forecasts. The results of both tests show that the developed models are capable of predicting areawide trip frequency, trip duration, and mode choice for various U.S. urban areas. The accuracy of these forecasts is comparable to that of specific models developed for particular areas as shown in zonal travel demand modeling experience. Demand for Freight Transportation with a Special Emphasis on Mode Choice in Canada, Tae Hoon Oum, 1979, (Dissertation at the University of British Columbia, Vancover, B.C., Canada). This thesis derives a freight transportation demand model consistent with neoclassical economic theory: a
in every instance, in the public interest by the Commission; (9) entry control in all its ramifications has stifled the growth of the contract carrier industry and the individual contract carrier; (10) in recent years, the regulatory environment and Commission policies, pertaining to entry control in the motor carrier industry, is changing, from one which promoted the growth and health of existing firms and fewer firms, to one which promotes entry of a larger number of small firms, especially contract motor carriers; (11) total deregulation is not required to regulate contract motor carriers in the public interest, but changes are required to more effectively regulate contract motor carriers; and (12) the necessity for regulating contract carrier rates and services, including publication of such rate schedules, cannot be economically supported.
245
mechanisms; however, no significant positive associations with service performance were found for these concepts. In fact, internal control mechanisms generally displayed significant negative associations with service. Considering the study’s economic variables, a major finding was that vanlines display a greater sales orientation, a greater profitability, and a worse service performance record. This finding implies that the industry might face certain structural defects. since C.O.D. service deficiencies are not economically sanctioned by the market. Possible institutional arrangements are therefore presented as policy options to improve the linkage between service and financial performance and to dampen vanline sales orientation.
Demand Analysis
Household Goods Carrier Systems: Organized Control of Member Agents and Owner-Operators, Edward Anthoney Morash, 1979, UMI 7926495 (Dissertation at the University of Maryland, College Park, MD 20740). This dissertation is a study of the household goods moving industry, and in particular, a study of the control and operating practices of household goods firms. The major hypothesis tested was that those parent household moving systems which exercise greater external control over member agents and owner-operators exhibit superior service and financial performance. Several subsidiary hypotheses were concerned with the types of external and internal control and their relationships to performance. Another group of hypotheses was directed at testing the relationships between performance and a group of economic and structural variables such as firm size, sales orientation, and firm structure. The primary theoretical basis for the research questions was organizational control theory and particularly the external-internal contingency approach. The independent variables relating to control types were measured by a survey instrument. Of the 332 Class I and II household goods carriers surveyed, 202 responded for a 61 percent response rate. The performance measures were obtained from Interstate Commerce Commission data. The primary statistical approach for the analysis was multiple regression. The major findings of the study were that smaller non-agency carriers made greater use of personal control mechanisms which tended to relate positively with service performance. Moderately sized agency systems with less than 75 agents made greater use of detailed administrative or output control which also related positively to service performance measures. For the largest agency systems, the emphasis was on broad administrative or output control which showed some tendency to be related with effective service performance. Other control concepts which were characteristic of larger agency systems included the exercise of expert power,formal training mechanisms, monetary rewards, and internal control
Prediction, Models and Data: An Analysis of Disaggregate Choice Models, Youssef Dehghani-Ghotbabadi, 1980, UMI 8027598 (Dissertation at the State University of New York, Buffalo, NY 14214). In the study several issues important to travel demand analysis were studied. These included: data accuracy and its effects, model and variable specification, modal aggregation, market segmentation, tests of the IIA property, and forecasting accuracy. The comparison of observed (manually coded) and network based level-of-service attributes showed that especially the excess time components are poorly calculated by the network. However, the total travel time is approximated quite accurately by the network for car and bus modes but not for BART (rail). This was attributed to the difficulties in including access mode and station choices into the network models. Coefficients estimated with the two types of data were not numerically similar. Statistical tests showed that the modal constants were different even though the cost coefficients were different by a fourfold margin in most of the models estimated. The reason for this discrepancy was attributed to the way parking costs have been calculated and assigned to the travellers by the network. Statistical results showed that the most satisfactory specification for travel time components is to lump them together : another interesting result is that the alternative specific constants for rail modes and express bus modes’ constants were found to be valued equally. A simple method was successfully used to aggregate rail and bus modes. The resulting coefficients of corresponding variables among all the models were consistent as they were statistically equal and numerically very close. No clear cut answers were found regarding the advantages of dividing travellers into homogeneous groups. Market segmentation by household income seems to be warranted on the basis of model estimation, while market segmentation by other variables-namely, CBD-bound travellers vs others and car owership variables-did not appear necessary.
246
Bibliographic
It was found that MNL-model is robust with respect to the independence of irrelevant alternatives (HA) property and only sensitive to the aggregation of auto modes but not of bus modes.
The Effects of Personality on Recreational Travel Behavior, Gokmen Ergun, 1979, UMI8008159 (DisUniversity, Evanston, sertation at Northwestern IL 60201). The goal of this study was to investigate the effects of personality on various components of the decision process related to recreation and recreation-travel related choices. Although various components on which personality may have some effect were identified, two of these were selected for inclusion in the research. These were the individual perception process, and the individual evaluation and choice process. Before the effects of personality on two components or the decision were analyzed, it was necessary to undertake a personality inventory related to recreation and the recreation-travel environment. Although some relevant scales were found in some extant inventories, these were lacking some concepts that were directly related to recreation choices. Therefore a major personality scale-construction effort was undertaken to construct these lacking scales. This effort resulted in twelve scales, six of which were selected-by some preliminary correlational analysis-for testing the effects of personality on the recreation-related decision components. The effects of personality variables on perceptions on recreation activities were tested using multivariate multiple-regressions; seemingly-unrelated regressions; multivariate analysis of variance and covariance; and their associated test statistics. These tests showed, quite that personality affects perceptions conclusively, significantly in the hypothesized manner. The effects of personality on rhe individual evaluation and choice process-which was represented by the recreation-activity preferences-were tested by building multinomial logit activity-choice models and using the associated test statistics. Personality variables were used both as alternative-specific additive terms and as segmentation variables. Both of these methods showed that these effects were highly significant and logical.
Generalization of Demand Models for Areawide Travel Forecasting. Fong-Lieh Ou, 1980, UMI 8101011 (Dissertation at the University of Utah, Salt Lake City, UT84412) With the emphasis in recent transportation planning on the needs of fast-response methodology, efforts have been made to test the transferability of travel demand models. There is, however, little evidence that models are transferable between geographical areas. It is the purpose of this research to determine the impact of urban character such as size class, activity concen-
Section
tration, and geographical cluster on urban travel demand, and to incorporate these characters into model development. The emphasis in this study is on the development of a model generalization procedure and the generalized areawide demand models which can be applied to various urban areas. The model generalization procedure begins with parallel steps of variable selection and model structure development. and then estimates and verifies the preliminary models. Following these steps the procedure goes on to develop and validate generalized models. Chow’s test is employed to examine the model stability over time; Ott’s test is utilized to determine the statistical significance of urban character: and the generalized dummy variable approach is applied to account for possible effects of urban character on travel demand. The generalized models are designed to predict areawide trip frequency, trip length, and mode choice for non-metropolitan and metropolitan areas, and to provide estimates on total person trips, person-miles-of-travel, and person-hours-of-travel. These measures are postulated to be dependent upon the activity and transportation system variables and influenced by urban character. For non-metropolitan areas. trip frequency and trip length models are developed. The trip frequency is a function of auto ownership and household size, while the trip length is a function of population. The relationships of these two models are affected by the type of activity concentration and by geographical cluster. For metropolitan areas, demand models are developed for the trip frequency, trip length as well as mode choice. The trip frequency is related to auto ownership, household size, and population, and is affected by geographical cluster. The trip length is dependent upon population, land area, and population density, and is affected by urban size class, activity concentration, and geographical cluster. The travel by auto is explained by auto ownership and population density, the travel by transit is a function of auto ownership, population density, and population, while the travel by walk is related to auto ownership and the supply of transit service. These relationships are by and large affected by urban size class and geographical cluster. The data for the empirical estimation of the models is a nationwide sample of 1960’s. The predictive ability of the models is validated by the backward and forward forecasts. The results of both tests show that the developed models are capable of predicting areawide trip frequency, trip duration, and mode choice for various U.S. urban areas. The accuracy of these forecasts is comparable to that of specific models developed for particular areas as shown in zonal travel demand modeling experience. Demand for Freight Transportation with a Special Emphasis on Mode Choice in Canada, Tae Hoon Oum, 1979, (Dissertation at the University of British Columbia, Vancover, B.C., Canada). This thesis derives a freight transportation demand model consistent with neoclassical economic theory: a