Review of ‘Forecasting Urban Travel: Past, Present and Future,’ by David Boyce and Huw Williams

Book Review:

BoyceWilliamsForecasting Urban Travel: Past, Present and Future, by David Boyce and Huw Williams. 2015. Cheltenham, U.K. and Northampton, Massachusetts: Edward Elgar. 650 + ix. ISBN: 9781848449602.

David Boyce and Huw Williams have written the definitive history of travel demand modeling to date. The book really begins (chapter 2) with Douglass Carroll, whose innovations in Detroit, and then in Chicago, developed the foundational four-step transportation planning forecasting tool that is widely used and abused in metropolitan areas across the globe. The aim at the time was to develop forecasts of future traffic—how many trips, where are they going, how many would drive, and which routes would they use—that could be used to locate and size freeways being deployed with the upcoming Interstate Highway System. In one sense, it was enormously successful, as the model spread from the Midwest of the United States across the globe, and has been used to conduct analyses, inform, and justify projects. It also spurred enormous methodological advances, one of which earned Daniel McFadden a Nobel Prize in economics for his work on developing random utility choice models.

After developing the framework, the book explores the formalization of spatial interaction models, especially the work of Alan Wilson (chapter 3), as well as the emergence of choice models in the 1960s, through development and generalization of the multinomial logit in its many, many forms (chapters 4 and 5), and the unification of the two. I have experience working as a travel demand modeler, so while it was familiar territory, it was also clarifying in many ways. Reading the book, I understood the linkages far more deeply than before. One of the merits of the book is the hiding of most of the mathematics in the end notes. (Note 1) The book also provides a very detailed history of developments in the United Kingdom and some discussion of developments in other European countries, in addition to the history from the United States’ perspective, providing a more global perspective on the issue. I was not aware the East Germans had developed their own modeling methods, and remain curious about practices elsewhere in the Eastern Bloc.

The book turns to the present trend in microscopic models, including activity-based models (chapter 6), which model tours of individuals rather than trips of aggregate flows, and the Transims project (chapter 8). From a methodological perspective, this is clearly an improvement, and the direction most applied models seem to be moving toward. By recognizing time-space constraints as formulated by Ha ̈gerstrand, the models become more realistic. If it were presented clearly to the public, it would probably be more intuitive and comprehensible than traditional aggregate models. This has not improved their predictive value, however, and Transims was, as the book describes, a diversion of resources with little to show for it.

After dealing with the first three steps of the travel demand model, the book then discusses network equilibrium and solution methods for route assignment or route choice (chapter 7). These evolved independently from the work of Beckmann, McGuire, and Winsten in the 1950s (coinci- dentally also in Chicago, though not interacting with Carroll’s group), were operationalized with steadily improving algorithms in the 1970s, and were mainstreamed into practice by the late 1980s. While equilibrium for route choice is now standard (whether or not traffic is in equilibrium, and whether or not route choice depends solely on travel cost), there is no standard “feedback” method to ensure that the travel time inputs to the travel demand process are consistent with the travel time outputs of route choice procedures, one of the many problems with actual transportation modeling practice, and a problem that as the authors note has received insufficient attention in the literature (the authors notably excepted).

Travel demand models have their uses. Long-term forecasting—their putative rationale—is probably the weakest. Yet, this entire enterprise was nominally driven by the desire to forecast travel demand, not simply understand or model it. It is indeed in the title of the book. On that score, the field has, in my opinion, failed miserably. Boyce and Williams note that accuracy is poor, and not improving over time. While one can understand the naivety of early modelers in the 1950s and 1960s (who undoubtedly well understood the limitations), by the 1970s (and certainly by the 2010s), the futility of accurate forecasting should have become apparent to those both within and outside the field. The forecasts are driven by the assumption that behavior in the future, given identical characteristics, will be the same as today. Culture is outside the scope of models, with good reason, but if culture matters, or anything else that is also outside the model’s data, there will be misses. Modelers may claim data issues, or poor inputs, and those certainly matter, yet as the authors note, estimation of models across time is never done in practice. There are always reasons— incompatibility of surveys, time, budget, and so on. The excuse for using cross-sectional analysis in the 1950s was that there was no time series; only one survey (at most) had ever been done in any metropolitan area. The excuse today is what?

In addition to behavior being static in these models, technology is as well. As the book notes, use of stated preference models to examine what would happen given a new technology attempts to push the boundaries of this, but it fails to say what technologies will actually be around, which will affect demand in ways we just have to admit that we cannot accurately foresee. This issue is increasingly important as new modes like shared autonomous vehicles are being considered, and autonomous vehicles (even if unshared) change the character of automobile travel. That a forecasting tool considering 30 years into the future cannot consider the possibility of such change in any reliable way suggests that it is probably not the right tool.

For this reason, these travel demand forecasts, at one time the most sophisticated analyses done by humans with their early use of mainframes (described in chapter 10), fall into the same trap as much simpler forecasts: underestimating growth in the early years of a technology’s life cycle and overestimating in the late stages. Boyce and Williams note the many problems with forecasts toward the end of the book (chapter 11), but remain more optimistic than I would. I believe the field should take its tools and apply them where they might be useful: short-term analyses of minor changes, scenario analyses of alternatives, but most definitely not forecasts. This requires changing evaluation procedures and government regulations. However, there are enough problems today that remain unsolved, so that looking for problems 20–30 years down the road seems futile.

In the end, this book serves as an excellent history of ideas about the research and its application in travel behavior and travel demand modeling forecasting, and should be widely read by researchers and practitioners in the field, and owned by their library. In my mind, however, it is a history of proceeding very deeply down the wrong rabbit hole, of systematic application of mathematical methods providing a veneer of science to cover, in the end, for political decisions.

— David Levinson

The Review appears in Journal of Regional Science June 2016 issue: http://onlinelibrary.wiley.com/doi/10.1111/jors.12273/full


Notes:

1 As Alfred Marshall wrote: “But I know I had a growing feeling in the later years of my work at the subject that a good mathematical theorem dealing with economic hypotheses was very unlikely to be good economics: and I went more and more on the rules—(1) Use mathematics as a short-hand language, rather than as an engine of inquiry. (2) Keep to them till you have done. (3) Translate into English. (4) Then illustrate by examples that are important in real life. (5) Burn the mathematics. (6) If you can’t succeed in 4, burn 3. This last I did often.” pp. 427–428 of Memorials of Alfred Marshall, edited by A. C. Pigou. One edition is: New York, A. M. Kelley, 1966.

Review of The Transportation Experience

Frank Manheim at GMU reviews The Transportation Experience, Second Edition.  [copied below from Journal of Planning Education and Research 36(2) p.271-72 (behind a paywall)]

The Transportation Experience: Second Edition
The Transportation Experience: Second Edition

Garrison, William L., and David M. Levinson. 2014. The Transportation Experience. Oxford: Oxford University Press. 605 pp. $92.00 (paperback). ISBN 978-0-19-986271-9

Reviewed by: Frank T. Manheim, George Mason University DOI: 10.1177/0739456X16644800 

The Transportation Experience offers unique breadth of scholarship in describing the history of US transportation. Its erudition and insightful links with other aspects of societal evolution are improbably combined with an informal, colloquial style that makes most of the book widely accessible. However, a curious omission emerges as the narrative reaches the modern era. The senior author acknowledges in his afterword that he deliberately minimizes engagement with politically controversial subjects.

The first paragraph already demonstrates the book’s flair for dramatic impact. It describes actions of Thomas Jefferson, head of the US Patent Office, on August 26, 1791. Four applicants sought patents for complete steamboat designs. “Solomonically dividing the patent spoils kept any from dominating the market and developing a large enough market to succeed” (3). The multilevel insights from this anecdote reveal that Jefferson, the brilliant inventor, naturalist, and intellectual and political leader, made a decision that impeded people and progress he wanted to encourage. The primary source of such erudition is the senior author, William L. Garrison, a professor emeritus at the University of California, Berkeley. His peripatetic studies over more than a half-century (Garrison was born in 1924) complement the book’s detailed account of transportation with insights from tangential fields like history, engineering, economics, and social psychology.

This second edition is completely restructured, extensively rewritten, and augmented in comparison with the first edition of 2005. In contrast to the first edition’s prefatory discussions, this book has no preface, introduction, or discrete acknowledgments. It is far more tightly organized. After a detailed table of contents, the treatment is divided into parts, thirty-five numbered sections that run through five overlapping “waves” of chronological developments, and “phases of the life cycle,” that the authors initially describe as brainstorming sessions.

Grounded as it is in deep scholarship, the colloquial style of the book probably reflects contributions by the junior author, David Levinson, a civil engineer and professor at the University of Minnesota who has special interest in transportation. But addressing readers more personally also appears congenial to Garrison. He closes by offering an invitation to readers to “have fun imagining alternative development pathways that will exchange today’s problems, both obvious and obscure, for new ones” (p. 524).

Wave 1 (1790–1851) is subdivided into three sections: “Rivers of Steam” describing the early history of the steam

engine, the steamboat, and inland waterways; “Design by Design: The Birth of the Railway”; and “Incentivizing Investment: Roads through the Turnpike Era.” Subsequent waves deal not only with new subjects like maritime transport, including trading companies, ports, cargo and passenger vessels, and biographical detail on the great marine engineers, Marc and Isambard Brunel. They update developments in earlier transportation modes like railroads (Wave 2, 1844–1896) with topics as diverse as “Trial and Error,” “Learning about Freight Rate-Making,” “Cornelius Vanderbilt,” and “Comments by Social Critics.” Waves 3, 4, and 5 encompass the periods 1890–1950, 1939–1991, and “Modern Times,” respectively.

The waves focus on but are not limited to their time period. Events are often placed in historical perspective by chronological profiles extending to the present.

Many of the book’s figures and tables qualify as what l call leveraged illustrations. Such illustrations compress important insights and in-depth research into simple and eas- ily understandable figures. For example, Wave 2 includes a plot of total US railroad route kilometers from 1830 to 2010, peaking in 1920. Subsequent declines in route kilometers have an inflection point marking accelerated losses after 1970. Most other advanced nations experienced losses but none as great as this country.

“Life cycle” discussions clarify factors affecting transportation and related fields. Phase 1 of the life cycle discusses inventing and innovations. Phase 2 introduces the concept of the “magic bullet,” which refers to innovations that make possible reductions in cost, and often make gains in convenience and accessibility. Henry Ford’s assembly line is a classic example. Impactful generalizations allow readers to independently discern nontransportation as well as transportation applications. For example, I identified the supermarket, Amazon, and Ebay as non-transportation magic bullets.

Phase 3 of the life cycle, titled “Aging in Place, Aging sans Grace,” describes a central problem for transportation. “As systems transition from innovation through growth to maturity, the administration of the systems transitions from entrepreneurs and engineers to managers. Organizations become more and more risk averse; taking chances tends to be punished.” Section 18 includes a summary of leading theories and strategies for coping with the problem.

The authors like evocative labels for their waves, such as “Lord Kelvin’s curse” (in Wave 4, 1939–1991). This “curse” is defined as work that puts emphasis on numbers rather than thinking. Among examples, the authors cite the advent of the Universal Urban Transportation Planning System (UTPS), which created a “clean break from precursor planning systems.” However, modern UTPSs “ignored the well-honed planning techniques for arterial roads and local streets lodged in urban public works offices.”

Section 24 provides a brief discussion of theoretical topics such as temporal and spatial dynamics, the network design problem (NDP), “Macro-Economics vs. Life Cycle Economics,” queuing models, metacycles, and historic path dependence. Section 26, “Meta-cycles,” which closes Wave 4, deals with capital, cyclicity, and the new role of innovation in the production function.

“Wave Five: Modern Times” faced a challenge because of difficulty in addressing the vast literature and complex controversies over environmental change and energy in limited space. A good opening of this topic is provided by reference to George Perkins Marsh’s pioneering and influential book Man and Nature (1864), which warned Americans about abuse of the natural environment (the date of its first edition is erroneously cited as 1850). The ensuing treatment provides basic data such as energy consumption and use by auto, air, and rail transportation after World War II, but this section largely ignores a huge rhinoceros in the living room: government policies and sociopolitical issues.

The great strengths of the book are already suggested in its first paragraph. Heading these is its formidable scholarship in transportation history. Next, wide-ranging technologies, evolutions, and human responses encountered in the development of transportation systems are described with an irreverently colorful and informal writing style. The authors have the rare gift of using detail to clarify and enliven rather than to complicate and obscure generic concepts like “disjoint incrementalism.” Disjoint incrementalism refers to improvements or expansion of technology in one area that ignores possible adverse effects on others. It is illustrated by truckers’ adoption of high-pressure radial tires that disproportionately damage roads. No other book offers as great a wealth of historic detail, presented in vital and candid ways. Consistent clarity in explaining terms and concepts while the narrative builds a detailed framework of knowledge makes the book highly recommendable for non- specialists and beginning students as well as a basic historical reference for professional practitioners and academic researchers.

The startlingly and inappropriately minimal space given to law, politics, and governmental policies is due in large part to the authors’ stated principle of not commenting on “today’s debates and actions” (p. 412). The senior author says about this policy in his part of the Afterwords: “I wear one hat when judging whether or not to enter ongoing affairs. I wear a second hat when debating goals, programs, opportunities, etc.”

Garrison’s honesty about avoiding politically contentious subjects is consistent with the book’s open style and contrasts with some academic studies that simply dance around sensitive issues. But what is the point of devoting such concentrated thought and space to nonpolitical transportation issues if they are overridden in importance by government policies and politics? Rietveld and Stough (2007) indicate that it is possible to address sensitive topics like regulatory reform (or deregulation) while retaining scholarly objectivity. These authors as well as Black (2003) review important insights from European nations’ experience, another area largely omitted by Garrison and Levinson. Author Levinson would apparently be readier to grapple with politics, judging from his account in the Afterwords of the failure of the I35W bridge over the Mississippi River at Minneapolis. He cites existence of 72,500 structurally deficient bridges in the United States, concluding that “Americans can seem good at short-term tactics but poor at long-term strategy. This needs to be rectified.”

The critical role of government for good or ill is hard to overestimate. Excessive regulation helped undermine the United States’ passenger rail system (Gallamore and Meyer 2014). The Clean Air Act Amendments (1970 and later) were effective in reducing air pollution but had unintended adverse effects on urban areas’ transportation planning systems (Garrett and Wachs 1996). Uncoordinated proliferation of permitting authorities in response to environmental concern in the 1970s is described by Manheim (2009) as a key factor in delays and increases in the cost of transportation and other major construction projects. The Chrysler building, a revered jewel in New York City, was completed in twenty months from 1928 to 1930. Contrast this with Boston’s scandal-ridden Big Dig. Permitting began in 1982, final approval was received nine years later, and highway I93 was fully opened only in 2005.

The book by Garrison and Levinson can be warmly recommended as a mine of information on US and early UK transportation development in a broadly based historical framework. The twenty-seven pages of references provide documentation of the book’s data. However, they do not provide balanced coverage, leaving out reference to authoritative and influential transportation authorities like William R. Black and John R. Meyer. Finally, the book does not provide adequate treatment of contemporary transportation problems or foreign experience.

References

Black, William R. 2003. Transportation: A Geographic Analysis. New York: Guilford Press.

Gallamore, Robert E., and John R. Meyer. 2014. American Railroads: Decline and Renaissance in the Twentieth Century. Cambridge, MA: Harvard University Press.

Garrett, Mark, and Martin Wachs. 1996. Transportation Planning on Trial: The Clean Air Act and Travel Forecasting (Metropolis & Region). Thousand Oaks, CA: Sage.

Manheim, Frank T. 2009. The Conflict over Environmental Regulation in the United States: Origins, Outcomes, and Comparison with the EU and Other Regions. New York: Springer.

Rietveld, Peter, and Roger Stough, eds. 2007. Institutions and Sustainable Transport: Regulatory Reform in Advanced Economies. Cheltenham, UK: Edward Elgar.

Improving Urban Access: New Approaches to Funding Transport Investment

A new book is out, I had the opportunity to preview and blurb it:

Improving Urban Access: New Approaches to Funding Transport Investment

Edited by Elliott D. SclarMåns LönnrothChristian Wolmar. 2016 – Routledge

 

Reviews

“Improving Urban Access” provides a wide-ranging introduction to the issues of funding and financing urban transport, ranging from how we got into the current predicament to the prospects for a variety of solutions that might make transport more inclusive, efficiently funded, and soundly managed. The ideas discussed here should be deeply understood by everyone concerned with transport policy and planning.” – David M. Levinson, Professor, Department of Civil Engineering, Richard P. Braun/CTS Chair in Transportation Engineering

Improving Urban Access is a must-read for the 21st century generation of transport and urban planners. Lessons learned have called for a bold rethinking of planning and implementation of a highway-centered landscape. With an emphasis on access – where access addresses quality of life and place, old models of mobility give way to rethinking the institutions that serve our growing urban areas, the ways in which citizens can finance new transport modes and how – we can achieve a more equitable social structure.” – Robert E. Paaswell, Distinguished Professor City University, City College of New York, former CEO of the Chicago Transit Authority

“Many public servants are so desperate to “find” additional revenues for urban transportation that they may lose sight of what they are trying to accomplish and why. This book does an excellent job of reminding us that how something is funded directly impacts the societal outcomes we are wishing to achieve, pointing out that careful consideration of funding mechanisms is absolutely critical to success.” – Joshua Schank, Chief Innovation Officer, Los Angeles County Metro, former President of the Eno Center for Transportation

“Transportation policy scholarship is changing slowly but dramatically, and this second stimulating milestone book by these editors charts that transition. Contributors forcefully address the most important unresolved questions as transportation thinking moves from forecasting demand and providing facilities to a new emphasis on access, social and economic equity, and environmental sustainability.” – Martin Wachs, Distinguished Professor Emeritus, Urban Planning and Civil Engineering University of California Los Angles and University of California, Berkeley

The Transportation Experience: Cover Art

The Transportation Experience: Second Edition by William L. Garrison and David M. Levinson
The Transportation Experience: Second Edition by William L. Garrison and David M. Levinson (2014)
Claude Monet  - Gare Saint Lazare (1877)
Claude Monet – Gare Saint Lazare (1877)

 

The cover art for the Second Edition of The Transportation Experience is Gare Saint-Lazare (1877) by Claude Monet. A full discussion of the art can be found at the National Gallery of Art exhibition brochure.

The steam and the perspective, and the common theme of trains and rails evoke the earlier impressionistic (though not necessarily impressionist) Rain, Steam, and Speed by JMW Turner which we used on the cover of the First Edition. Monet’s image is set in a station rather than in motion, and in urban Paris rather than the countryside of England at Brunel’s Maidenhead Railway Bridge, but if you look closely, you see structures in the background of both.

The book is available for order at Oxford University Press,  Amazon and Barnes and Noble

The Transportation Experience - First Edition by W.L. Garrison and D.M. Levinson (2005)
The Transportation Experience – First Edition by W.L. Garrison and D.M. Levinson (2005)
Rain, Steam and Speed - The Great Western Railway by J.M.W Turner (1844)
Rain, Steam and Speed – The Great Western Railway by J.M.W Turner (1844)

 

Garrison, W.L. and Levinson, D.M. (2014) The Transportation Experience: Policy, Planning, and Deployment – Second Edition. Oxford University Press

ISBN-10: 0199862710 | ISBN-13: 978-0199862719 | Edition: 2

 

The Transportation Experience – Reviewer Comments

The Transportation Experience: Second Edition by William Garrison and David Levinson
The Transportation Experience: Second Edition by William Garrison and David Levinson

My author’s copy of The Transportation Experience just arrived, so it is a good time to talk about the book, which will be available is available for pre-order now. Below are comments from reviewers.

Garrison, W.L. and Levinson, D.M. (2014) The Transportation Experience: Policy, Planning, and Deployment – Second Edition Oxford University Press

Publication Date: February 3, 2014 | ISBN-10: 0199862710 | ISBN-13: 978-0199862719 | Edition: 2

“It’s hard to imagine a more comprehensive survey of transportation history than The Transportation Experience. The book guides readers from the days of steam engines and turnpikes to those of high-speed trains and robot-driven cars-blending top academic insight with colorful biographical bites. Whether your interest is infrastructure, public policy, transport theory, or just travel in general, you’ll grow wiser from the journey.” — Eric Jaffe, author of The King’s Best Highway

“Everything you wanted to know about transportation is in this book. It is not only a comprehensive look back at the transit methods that built the nation, but a look forward based on how the lessons from the past can be applied to the modern metropolitan economies. This book could not come at a better time.” — Robert Puentes, Director, Metropolitan Infrastructure Initiative, Brookings Institution

The book is available for pre-order at Oxford University Press,  Amazon and Barnes and Noble

5 or so Books about Minnesota, Transport, and Land Use You Should Read — streets.mn

I have a post up at Streets.MN: 5 or so Books about Minnesota, Transport, and Land Use You Should Read. The whole post is below:

You are reading Streets.MN, you might have something to do with Minnesota, Transport, and Land Use, and you are probably literate. Here are some books you should read.

Main Street by Sinclair Lewis
Main Street by Sinclair Lewis
  1. Lost Twin Cities – Larry Millett
  2. Twin Cities by Trolley by John Diers and Aaron Isaacs
  3. Main Street by Sinclair Lewis
  4. Minnesota in the 70s by Dave Kenney and Thomas Saylor
  5. Potluck Supper with Meeting to Follow: Essays by Andy Sturdevant

What else you got? Add more to the comments:

5 or So Books on Transportation Economics and Policy You Should Read

The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger by Marc Levinson
The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger by Marc Levinson

You are sitting by the fire, in your leather chair that just reeks “old money”, a reading light behind you, in your smoking robe and slippers, Labrador Retriever by your feet, pipe in one hand, a good book in another. What is that good book? Something about transportation economics and policy of course. Here are some of my favorites …

  1. The Box: How the Shipping Container Made the World Smaller and the World Economy Bigger – Marc Levinson (no relation, though I met him once) [review]
  2. Megaprojects and Risk: An Anatomy of Ambition – Flyvbjerg, Bruzelius, and Rothergatter [review]
  3. Mega-Projects: The Changing Politics of Urban Public Investment – Altshuler and Luberoff
  4. Going Private – Jose Gomez-Ibanez and John Meyer
  5. Curb Rights – Daniel Klein, Adrian moore, and Binyam Reja

5 or So Pieces of Children’s Transportation Fiction You Should Read (With Your Kids)

Thomas the Tank Engine by Rev. W. Awdry
Thomas the Tank Engine by Rev. W. Awdry

If you believe your kids should be indoctrinated in transportationism, you will get them appropriate books. While transportation fiction is a narrow category, kids books about transportation are plentiful. Here are some books and stories I liked for which the transportation technologies are important elements and geared toward younger readers.

  1. The Phantom Tollbooth (book and movie)
  2. Go, Dog, Go! – PJ Eastman (the abridged version is almost poetic)
  3. Don’t Let the Pigeon Drive the Bus – Mo Willems
  4. The Railway Series –  Rev. W. Awdry
  5. Richard Scarry’s What Do People Do All Day

Suggest more in the comments

5 or So Pieces of Transportation Fiction You Should Read

HG Wells' Things to Come
HG Wells’ Things to Come

“But I like fiction”  you say. Well transportation fiction is a narrow category. Here are some books and stories I liked for which the transportation technologies are important elements.

  1. The Financier, The Titan, and The Stoic – Theodore Dreiser’s Trilogy of Desire
  2. The Roads Must Roll – Robert Heinlein
  3. The Trail of the Hawk – Sinclair Lewis (not Sinclair Lewis’s best, that would be Main Street, Babbitt, or Arrowsmith, but a really nice picture about the changes brought by the then new car)
  4. The Shape of Things to Come – HG Wells (the movie and book)
  5. The Odyssey – some dude named Homer

Suggest more in the comments