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Urban travel demand: A behavioral analysis
Bibliographic Section
Urban Travel Demand: North-Holland
283
A BehaviaraI Analysis, Thomas A. Domencich and Daniel McFadden, Publishing Company, Amsterdam, xv + 215 pp. 1975, $24.95.
Reviewed by Steven R. Lerman, Department of Civil Engineering, Massachusetts Institute of Te&nolonv. Cambridge,MA02139,U.S.A. Transportation planners are continually confronted with the need to make and use forecasts of future urban travel. In this book, the authors present a modelling approach which radically ditIers from travel demand forecasting methodologies currently in widespread use and develop a convincing theoretical and empirical case for changing current practice. The book itself is a significant revision of an earlier study released in 1972, and it is unfortunate that this volume was not published sooner. Those currently active in the field of travel demand research are by now fairly well-acquainted with much of the theory developed by the authors. However, for those who are interested in understanding and utilizing choice models, the book represents one of the few complete, rigorous treatments of the subject area. The entire book revolves on the single, intuitively obvious concept that the demand for travel arises from the choices made by individual travellers and households. As a consequence, it seems almost as obvious that travel models should, to the greatest extent feasible, describe this decision process. Such models are defined by the authors to be behavioral models, and have also appeared in the literature as disaggregate choice or disaggregate behavioral models. This modelling approach has in the past been directed principally towards studying mode choice decisions. The authors, however, extend this perspective by examhung (at least from a theoretical perspective) the entire spectrum of decisions relevant to transportation planning ranging from workplace and residential location to trip frequency, destination, mode, time of day and mode choice for non-work trips. It is worth noting that the hook is directedprimarily towards economists. Transportation planners will undoubtably have some ditliculty with some of the jargon used in the theoretical development of the modelling
approach, and readers who are unfamiliar with econometric theory may wish to skip some sections entirely. Nevertheless, the essential elements of Domencich and McFadden’s contributions can be gleaned without a detailed comprehension of the analytic details. Perhaps this work’s only substantive flaw lies in the empirical study used to illustrate the theory proposed. There are relatively subtle but sign&ant inconsistencies between the stated theory and the actual models estimated. The authors propose a way to decompose a single, comprehensive choice model dealing with all aspects of travel behavior into a sequence of models which can be estimated sequentially; each stage of the model has some composite measure created from the prior stage’s results. However, in actual practice the authors used a different composite measure which is just&d as a tlrst order approximation to the correct measure. This approximation is not computationally more convenient and has fairly significant errors under some circumstances. In addition, some of the models in the sequence do not match with those suggested by the theory. These shortcomings, however, are minor and arise principally because the empirical study is somewhat outdated. More recent studies have corrected some of these flaws, but little would be added to the book by the authors’ reestimating their models. Domencich’s and McFadden’s key contribution is a long overdue, comprehensive treatment of the theory of disaggregate travel demand models from the econometrician’s perspective, not a major empirical study. If many researchers, including this reviewer, are correct in their belief that disaggregate modelhi will be at the core of the next generation of travel demand forecasting models, this book will undoubtedly prove to be a seminal work in the evolutionary process of demand model improvement.
Roads and the Urban Envlrenment, Organization for Economic Cooperation and Development, 2, rue AndrbPascaL75775 Cedex 16, France, 190pp., 1975. Price $7.00. Reviewed by Werner Brilon, Institute for Traffic Engineering, University of Karlsruhe, D-7500Qrlsruhe, Germany The book is a collection of 37 brief papers on the environmental effects of road traffic. Among these effects, noise, vibration, air pollution, regulatory aspects and planning approaches play key roles. The papers were presented at an OECD symposium held in Madrid in October 1974. The symposium served the purpose of promoting the international exchange of information in the field of environmental research. The same intention is served by the book. of all the environmental effects of road trafhc, noise is
the factor to which most attention has been paid. One fundamental problem is the characterization of trafhc noise by evaluation indices. There is a tendency to make increasing use of the A-weighted time equivalent level, because of its practicability and its potential for noise prediction. However, there is no agreed solution to the relative valuations of noise at different times of the day. One proposal made wanted to describenoise by one single value over a 24 hour period. Further effort should be directed at a uniform noise index formula capable of
Urban Travel Demand: North-Holland
283
A BehaviaraI Analysis, Thomas A. Domencich and Daniel McFadden, Publishing Company, Amsterdam, xv + 215 pp. 1975, $24.95.
Reviewed by Steven R. Lerman, Department of Civil Engineering, Massachusetts Institute of Te&nolonv. Cambridge,MA02139,U.S.A. Transportation planners are continually confronted with the need to make and use forecasts of future urban travel. In this book, the authors present a modelling approach which radically ditIers from travel demand forecasting methodologies currently in widespread use and develop a convincing theoretical and empirical case for changing current practice. The book itself is a significant revision of an earlier study released in 1972, and it is unfortunate that this volume was not published sooner. Those currently active in the field of travel demand research are by now fairly well-acquainted with much of the theory developed by the authors. However, for those who are interested in understanding and utilizing choice models, the book represents one of the few complete, rigorous treatments of the subject area. The entire book revolves on the single, intuitively obvious concept that the demand for travel arises from the choices made by individual travellers and households. As a consequence, it seems almost as obvious that travel models should, to the greatest extent feasible, describe this decision process. Such models are defined by the authors to be behavioral models, and have also appeared in the literature as disaggregate choice or disaggregate behavioral models. This modelling approach has in the past been directed principally towards studying mode choice decisions. The authors, however, extend this perspective by examhung (at least from a theoretical perspective) the entire spectrum of decisions relevant to transportation planning ranging from workplace and residential location to trip frequency, destination, mode, time of day and mode choice for non-work trips. It is worth noting that the hook is directedprimarily towards economists. Transportation planners will undoubtably have some ditliculty with some of the jargon used in the theoretical development of the modelling
approach, and readers who are unfamiliar with econometric theory may wish to skip some sections entirely. Nevertheless, the essential elements of Domencich and McFadden’s contributions can be gleaned without a detailed comprehension of the analytic details. Perhaps this work’s only substantive flaw lies in the empirical study used to illustrate the theory proposed. There are relatively subtle but sign&ant inconsistencies between the stated theory and the actual models estimated. The authors propose a way to decompose a single, comprehensive choice model dealing with all aspects of travel behavior into a sequence of models which can be estimated sequentially; each stage of the model has some composite measure created from the prior stage’s results. However, in actual practice the authors used a different composite measure which is just&d as a tlrst order approximation to the correct measure. This approximation is not computationally more convenient and has fairly significant errors under some circumstances. In addition, some of the models in the sequence do not match with those suggested by the theory. These shortcomings, however, are minor and arise principally because the empirical study is somewhat outdated. More recent studies have corrected some of these flaws, but little would be added to the book by the authors’ reestimating their models. Domencich’s and McFadden’s key contribution is a long overdue, comprehensive treatment of the theory of disaggregate travel demand models from the econometrician’s perspective, not a major empirical study. If many researchers, including this reviewer, are correct in their belief that disaggregate modelhi will be at the core of the next generation of travel demand forecasting models, this book will undoubtedly prove to be a seminal work in the evolutionary process of demand model improvement.
Roads and the Urban Envlrenment, Organization for Economic Cooperation and Development, 2, rue AndrbPascaL75775 Cedex 16, France, 190pp., 1975. Price $7.00. Reviewed by Werner Brilon, Institute for Traffic Engineering, University of Karlsruhe, D-7500Qrlsruhe, Germany The book is a collection of 37 brief papers on the environmental effects of road traffic. Among these effects, noise, vibration, air pollution, regulatory aspects and planning approaches play key roles. The papers were presented at an OECD symposium held in Madrid in October 1974. The symposium served the purpose of promoting the international exchange of information in the field of environmental research. The same intention is served by the book. of all the environmental effects of road trafhc, noise is
the factor to which most attention has been paid. One fundamental problem is the characterization of trafhc noise by evaluation indices. There is a tendency to make increasing use of the A-weighted time equivalent level, because of its practicability and its potential for noise prediction. However, there is no agreed solution to the relative valuations of noise at different times of the day. One proposal made wanted to describenoise by one single value over a 24 hour period. Further effort should be directed at a uniform noise index formula capable of