Transportation forecasting: A review

TECHNOLOGICAL FORECASTING A N D SOCIAL CHANGE

3, 367-389 (1972)

367

Transportation Forecasting: A Review DALE E. MeDANIEL Legs for the road The road for legs, Resolutely nowhere In both directions. from "The Legs" by Robert Graves Introduction Transportation has become a major force in our society. For at least the past ten years it has accounted for approximately 20 percent of the Gross National Product of the United States.[l] We have undergone what some observers have called a "mobility explosion."[2] There is a growing awareness of the role which transportation plays in shaping the way we live.[3] Man's seemingly insatiable desire to travel has given rise to all manner of speculation about how we might be traveling in the future. [4] At the same time, increasing attention is being devoted to techniques of forecasting, particularly technological forecasting, and long-range planning. [5] This attention isan apparent outgrowth of the realization that technological change is an accelerating process, and that it has seemingly placed in our hands an ability to shape our own future. In the words of Emmanuel Mesthene, "The power of this century's science and technology makes it possible to change the r u l e s . . , in the middle of the game. The temper of the times, in other words, is future oriented."[6] Peter Drucker expresses it somewhat differently when he says, "As an ultimate impact on man and his society, twentiethcentury technology, by its very mastery of nature, may thus have brought man face to face again with his oldest and greatest challenge: himself."[7] With this introduction, it is natural to inquire as to what ways the two forces have been combined. That is, how have technological forecasting and long-range planning been applied to transportation, a recognized major force in shaping our society ? This paper will examine that question. Further, the paper will examine the strengths and weaknesses of forecasting approaches which have been employed to date. Finally, some possibly useful directions for future work in transportation forecasting and planning are suggested. The review will concern itself primarily with the overall dimensions of transportation. It will not focus, except indirectly, on the individual modes of transportation. Neither will it consider individual features of transportation such as types of vehicles or means of propulsion, unless these relate directly to the total transportation spectrum. Finally, the study will deal primarily with movement of people, not goods. It is recognized that divisions such as those bounding this review cannot be so neatly made in practice. One could, for example, contend that it is the incremental changes in vehicles, propulsion systems, etc. which account for changes in transportation as a whole. As a matter DALEE. MCDANIELis General Engineer with the Merchant Marine Technical Division, United States Coast Guard, Washington, D.C. Copyright © 1972 by American Elsevier Publishing Company, Inc. 25

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of fact, Harmer Davis suggests this when he writes, " . . . the problem is one of producing incremental changes in a large, ongoing transportation complex."[8] Lending support to this concern is the fact that innovation is recognized to be an incremental process, not one ofsudden revelation. [9] We shall have more to say about the innovation process shortly. For the moment, while acknowledging possible limitations to the approach adopted, it might be justified on the grounds that only by having some conception of the larger whole can one meaningfully make sense of the individual parts. Or, as some observers hold, if you don't know where you are going, it doesn't matter which road you take. Additionally it can be noted that while there have been numerous incremental changes in the field of transportation, " . . . our urban centers have essentially the same basic modes of transportation as have been considered available since the turn of the century . . ."[10] There have been some, albeit few, studies which have concerned themselves with the total transportation picture. So consideration of the broad field is at least conceptually possible.

Factors Influencing Transportation Forecasting One factor influencing transportation forecasting is the process of technical innovation. The process of innovation has been given increasing attention in recent years. A great deal of this attention has been directed toward a retrospective examination of successful innovations, with the intention of applying findings to future situations. A case study by Elting Morison in 1950 summarizes five elements which were believed essential to successful technical innovation.[l l] It was found by Morison that the idea, the man and the background knowledge had to be brought together in a format which would admit the possibility of change. He also suggested that proposals for change usually occurred in an environment which reflects current knowledge and that resistance to change therefore was likely. Although based on a single case, Morison's findings have been generally confirmed by later studies. Recent work has modeled the process of innovation as three over-lapping stages: idea generation, problem solving, and diffusion.J12] Retrospective studies have tended to suggest that most technical innovations are need oriented. [13] That is, innovations are not usually undertaken simply because they are possible. Further, the need-oriented innovations tended to occur in smaller industries, whereas the technologically oriented innovations tended to occur in larger firms.[14] If these findings are generally correct, they will place great stress on techniques intended either to predict innovation or to channel innovation to a particular end. This is because it is not sufficient to confine the technique to one of considering the technical possibilities. Rather, one must also consider potential acceptance and usage of the development. Acceptance and usage are really inherent in the definition of technical innovation. There can be no innovation unless there is some incorporation into traditional behavior. An innovation may be relatively more or less successful depending upon the level of acceptance, but it must leave the laboratory or the drawing board to be considered an innovation. This leads to an interesting possibility, that of the non-innovation. W. L. Garrison concludes that we have a whole series of non-innovations in transportation, ranging from air ride vehicles to trains in tunnels. All of these are possible but may never be implemented;[15] hence, they are non-innovations. Many forecasting techniques seem to lose sight of the basic distinction between innovation and non-innovation, as we shall see when we examine some of the more specific forecasts. A second factor influencing transportation forecasting is closely related to the first.

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That is, to forecast with any degree of accuracy one must consider the general relationship among factors influencing change. We have seen in the previous paragraphs that efforts have been made to define the process of technical innovation in the context of social, economic, and cultural conditions as well as the general level of knowledge.[16] It becomes possible in this framework to consider short-range technical innovations (5-7 years) by recognizing the time lag between problem solving and diffusion stages of the innovation process and, essentially, holding the society and information levels constant for the purposes of the forecast. This framework has numerous limitations, however, if one wishes to go beyond the short-range projections or if one wishes to direct technological development to a given end. In this case technological possibilities must be considered in the context of society's wants and values, as interpreted by society's institutions. Elsewhere[17] this writer has suggested that such a framework might be as shown in the following diagram:

_r

\I /

POLITICAL I INSTITUTIONS [ ~ X FEEDBACK "\ \ \

,1 /s'/ f H UMAN GOALS (WANTS)

SCIENCE& TECHNOLOGY

~

I PRIMARY INFLUENCE

CULTURE (VALUES)

If one considers political institutions to represent the interpretative process of wants generally, the model becomes suitable for examining the context of technological change at any level. It is possible to focus attention on any of the elements of the diagram, which in practice are not entirely discrete. But a forecast will not be complete unless attention is given to the influence of each of the elements on the process under consideration. This is perhaps even more important for transportation than for other developments because transportation is seldom an end in itself. One does not generally travel simply to be moving, but rather to accomplish some other purpose, e.g., to get to work. Thirdly, transportation forecasting can only be undertaken in the context of transportation history. Without an appreciation for the historical developments in transportation, it is difficult if not impossible to judge the future. Two observations might be made in this context. First, modern transportation is a relatively recent phenomenon. Man really began moving extensively by mechanical means only when the steam engine was finally applied to water transportation (relatively unsuccessfully) by John Fitch in 1786.[18] Until that time, "The national horizon, in the eyes of the mass of the people (in the United States), still remained about two hundred miles from east to west."[19] The steamboat did not, of course come into general usage until around 1830. It was supplanted by the railroad in the 1860s, which was in turn supplanted by the automobile (as the principal means of moving people) around the turn of the century. The most recent mode of travel, the airplane, really only dates from the First World War. Thus, modern transportation, roughly, spans only the past 150 years. The second point of

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historical significance is that successively displacement of the primary means of moving people did not occur instantaneously. Around 1900, despite the fact that coast to coast railroads had been in existence for some 30 years, it was not uncommon for settlers to travel by wagon.[20] As each new mode was introduced, it was resisted by the then predominate mode, not unlike the resistance that Morison found when he studied the introduction of continuous aim firing in the Navy. [21] One would expect that it would require approximately a generation for the change to become accepted. In fact, if the dates of "domination" of the various travel modes are taken to be steamboats--1830, railroads--1860, automobiles--1900, and airplanes--1925, there is a time interval of approximately a generation between each mode. This is, of course, not exactly correct since for example the airplane has not really supplanted the automobile, but it does tell something about the way in which progress in transportation has occurred. By examining the reasons for changing preferences in travel modes, we might learn something of the direction which future preferences could take. We might also note that the really significant developments in transportation, excluding space travel, all occurred in the 100 year interval from 1830 to 1925. Since that time forms of travel have not changed. This has led some observers to caution that transportation development in the future must take a new direction, because the " . . . dramatic gains of the past 50 years cannot be replicated."[22] It does seem important, when forecasting the future, to occasionally glance over one's shoulder at the past. Finally, perhaps as the culmination of the past, transportation forecasting can only be undertaken on the basis of the current transportation patterns. Public acceptance of the various modes, investments in transportation networks, and resistance to change must be integrated into the forecasting pattern. There are other factors which may be identified as being important in transportation forecasting, and even those mentioned here might be classified by others in somewhat different ways. The importance of these elements is not in their exact definition, but rather in the way they influence the forecasting process. As we examine specific transportation forecasts, it may be useful to bear in mind the four features we have identified: the process of innovation, the context of change, the influence of the past, and the limitations of the present.

Review of Transportation Forecasts Forecasting techniques do not fall into neat categories. Depending upon the means of classification chosen, one could say there are two general types or perhaps hundreds. Jantsch has classified forecasting techniques into two categories, exploratory and normative.[23] Exploratory techniques begin with the present and examine in which directions technology is likely to take us. Normative techniques, on the other hand, assume some desirable future state and ask what measures are necessary to achieve that state. Ayres[24] classifies forecasting techniques somewhat differently, using a broader range of categories; he also incorporates various planning techniques which are closely related to, and essential to the implementation of, forecasts. Except for the purpose of giving some order to an otherwise nebulous field, however, specific classification of forecasts is unimportant. Some authors even go so far as to suggest that " . . . the success associated with any approach is more a matter of expertise in its use than in selection of the technique itself."[25] This seems an extreme view for which there would be little objective support--some techniques must be better than others for the specific task at h a n d - - b u t it does indicate the range of opinion on the subject. For the purpose of this review it is convenient to classify transportation forecasts under

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the headings of speculation, expert opinion, trend extrapolation, normative, transportation models, transportation planning, evaluation techniques, and social impact. Specific definitions of the various categories will be included under each heading.

Speculation Speculation is taken to be a personal evaluation of likely developments in transportation by one or more persons, based upon a subjective consideration of possibilities. There is no established framework to the forecasting process; it is more akin to science fiction writing. It is often assumed that the accuracy of such predictions is related to the expertise of the forecaster but this writer has found no objective evidence to support such an assertion. Success seems rather a function of the forecaster's imagination and his grasp of the factors which make technological innovation possible. In any event, no attempt has been made to determine the qualifications of forecasters grouped under this category. Speculation is the easiest of the forecasting techniques to use and is also the most widely employed. It is beyond the scope of this paper to conduct an exhaustive review of speculative transportation forecasts, but several examples should serve to illustrate results obtained by the method. C. A. O'Flaherty, a professor of transportation at Leeds University, England, has made one of the more comprehensive speculative forecasts of urban transportation. Based upon the assumptions that the standard of living will continue to rise; that quick and efficient travel will be a factor in this rise; that the population--particularly the urban population--will continue to increase; that personal transportation will continue to dominate travel; and that emphasis will remain on preservation of the central city, O'Flaherty makes several predictions.[26] Among these are the prediction that public transport will be increasingly justified on a social rather than a strictly economic basis. This is expected because of an anticipated increased recognition that society as a whole will gain from effective public transport.[27] As a result of this prediction, he makes several more specific ones: that high speed trains, VTOL aircraft, and hovercraft will cut into the domination of the automobile; new high speed modes such as the tracked air cushion vehicle and rail car ferry may come into common use; and that a continuous personal transporter will likely be developed.[28] Unless breakthroughs such as these occur, the metropolis may be forced to change its character by the year 2000 simply because transportation is inadequate.J29] Despite these inroads, he predicts that " . . . personal transport in the form of the private car will continue into the twenty-first century."[30] John Rae uses much the same reasoning as O'Flaherty in discussing the central city. He speculates that the only alternative to the automobile is more centralized living, and the auto is more acceptable for most people, ergo we should plan for the demise of the central city.J31] Others take a different tack. John Gibson, in keynoting the 1968 IEEE Symposium on National Transportation Requirements, noted Doxiadis' statement that the only truly viable urban environment was one which could be navigated on foot. Gibson suggests that "Either this should be recognized or the city should be redesigned to take into account rapid transportation."[32] Since people like their autos so much, however, a logical development would be the StaRRcar, a system whereby personal vehicles are under central control while on the main arteries and under individual control while in access routes.[33] But the foregoing are rather mundane speculations involving only urban transportation. Some speculators take a broader view. Hal Hellman constructs a personal scenario

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of all transportation systems in 1990 by which travel is swift, efficient, noiseless and almost totally under automatic control.[34] Putnam Beckwith predicts a continuous cultural homogenization over the next 500 years brought about by inventions (unspecified) which cheapen and increase travel and eventually result in international transportation monopolies.[35] After a comprehensive commentary on the science, or art, of technological forecasting techniques, Robert Prehoda launches into speculation regarding the future of transportation, among numerous other fields. His speculations seem more a shopping list of new technological possibilities than actual predictions. He predicts increased use of pipelines for all manner of goods, levapad (air cushion) monorail, two types of underground rapid "tube" transits, and widespread space travel.J36] His most specific prediction is an increase from 15--45 ~ in capacity of aircraft by 1980, which he thinks will reduce passenger and freight fares by two-thirds and displace trucks and rail.[37] Even these predictions have received rather widespread attention in the literature as being technologically possible.J38] Perhaps the most vivid imagination in this field belongs to Arthur Clarke, who looks forward to urban travel by a special breed of high intelligence animal which can be trained to deposit and collect his passenger, without resort to the need for parking space. Clarke prefers that the animal be herbivorous rather than carnivorous less it take a fancy to its passenger.[39] He also sees a great future for the VTOL aircraft and air-cushion vehicles, which are visualized as travelling over old and crumbling highways.[40] Once he gets warmed to his task, Clarke really turns it on. Next in his speculative bag is control of gravity, which would permit travel at little expenditure of energy. [41] This is pale by comparison to his musing regarding transmutation, which would permit not only instantaneous "travel" but also unlimited reproduction of the "traveler."[42] He is not at all certain about our capability for transmutation but concedes that, "It will be one of history's little jokes if, when we attain this power, we are no longer interested in using it."[43] Clarke is also one of the few speculative forecasters who recognizes the potential impact of communications improvement on transportation, although even he does not seem to view this as a limiting factor. While it makes interesting reading, there is of course little application for speculative forecasting other than to broaden one's mind as to the various possibilities. Some speculative forecasts have, of course, been amazingly accurate, such as Clarke's early prediction of the exact year of the first moon landing. But one success reveals very little regarding the future accuracy of such forecasts. About the only thing that might be said is that if another speculative forecast of moon landings is ever required, Clarke might be consulted. In general, one would probably profit by finding speculative forecasters who are always wrong rather than always right. A hypothesis to this effect, for business forecasting, is developed convincingly in The Peter Principle. Such a forecaster could "guide" your action by allowing you to always do the opposite of what he suggests. Considering the lack of success of most speculative forecasts there should be numerous candidates for the position.

Expert Opinion Expert opinion is probably a special category of speculative forecasting in which the individual claims for himself, or someone claims for him, special expertise in the particular field under consideration. This is also a widely used method of forecasting, the best known technique being Delphi. In Delphi, consensus among predictions by a panel of experts is sought by use of polling and feedback techniques designed to reduce the

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pressure of face to face group influence• At least two Delphi studies have been concerned with transportation forecasting• Both are portions of studies which were used for subsequent manipulations of the Delphi technique. These subsequent manipulations will be discussed in later sections• Presently it is of interest to review some of the Delphi predictions• The first study[44] included four items directly related to transportation• These items and the mean date at which the experts predicted a 50 percent likelihood of occurrence are as follows: • Widespread existence of regional high-speed transportation systems such as VTOL/STOL, G E M , 200 mph trains, and so on.

1990

• Widespread use of automobile engines, fuels, or accessories which permit operation without harmful exhaust•

1980

• Widespread use of surface effects ships for ocean transport

2000

• Routine use of reusable ballistic suborbital transports for military or commercial passenger and cargo transportation

2010

The second Delphi application was prepared by two experts in lieu of a panel for illustrative purposes in another connection.[45] The forecast list contains 72 items directly related to transportation and associated societal adjustments• While it is not a " f o r m a l " Delphi application some of the predictions are nonetheless interesting• In lieu of predicting the likely date of occurrence, these forecasts predict the probability with which an event is expected to occur within the next 20 years. Some of the events and their probabilities are as follows: • Automated highways which would track and control the speed and direction of vehicles traveling over them. • A storage battery which can power an automobile at 80 mph, over ranges up to 200 miles, weighing less than 200 pounds• •

Non-deflating tires•

.30

.90 .50

• Increased use of VTOL/STOL.

.80

• Increased use and performance of sub-surface trains for commuting at peak speed of over 100 mph.

.80

• Increased use and performance of private autos•

.90

• Increased desire for passenger comfort•

.70

The presumed advantage of the Delphi technique over speculation is that it is a consensus of experts in the field• This presupposes that because experts have knowledge of technological possibilities in the area that they are in a better position to predict the future• It fails to account for the fact that the very factors producing change may well lie outside of the field itself• The technique also sidesteps the issue of whether or not experts are any better at predicting than the novice• There are numerous examples which would give rise to doubts that they are better forecasters.J46] Even if these objections were overcome there is a more basic limitation to the method. As with speculative forecasting the basis upon which the prediction is made is subjective• That is, the predictor weighs in his mind those factors which he believes will influence innovation and makes his prediction on that basis. He has subsequent opportunities to revise his prediction in light of feedback from other panel members. This makes it

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impossible, of course, to determine the basis upon which the final prediction was made or what weight was given to which factors. I f two separate panels of experts made the same predictions under such conditions it would have to be attributable more to coincidence than to exactness of technique. There are certain appeals to the method, however, not the least of which is that it is fun to participate in such an exercise• This is no small matter. If people are to become seriously interested in thinking of the future, the exercise cannot be dull• Additionally, it causes the participants to focus on particular questions, which is important for the attention that it brings to the need for making decisions which will shape our future. Finally, by use of a number of persons, even though their weightings may be subjective, there is a greater possibility that all relevant factors will be considered•

Cross hnpact Matrix This is not really a method of forecasting• It is more a method, once a forecast or forecasts have been made, for determining the influence of one event on another• It is intended to overcome some of the subjectivity of forecasting methods• As T. J. G o r d o n and H. Hayward note, "A shortcoming of this (Delphi) and many other forecasting methods . . . is that potential relationships between the forecasted events may be virtually ignored and the forecasts might well contain mutually reinforcing or mutually exclusive items."[47] In order to avoid this, a method of systematically evaluating potential relationships was developed• This method, called cross impact matrix analysis, displays all events being forecast in the form of a matrix, and the influence of each item on each other item in the matrix is estimated. The second Delphi experiment on transportation forecasting previously discussed was used to evaluate the cross impact matrix method• The results are interesting. For those items previously listed, their initial and final (after cross impact analysis) probabilities are given below• It will be recalled that the probabilities are the likelihood that the event will occur within the next 20 years•

hlitial

Final

• Automated highways which would track and control the speed and direction of vehicles traveling over them.

.3000

.9430

• A storage battery which can power an automobile at 80 mph, over ranges up to 200 miles, less than 200 lbs.

.9000

.9100

• Non-deflating tires•

.5000

.8770

• Increased use of VTOL/STOL.

.8000

.9460

• Increased use and performance of subsurface trains for commuting at peak speed of over 100 mph.

.8000

.9270

• Increased use and performance of private autos.

.9000

.9260

• Increased desire for passenger comfort•

.7000

.9240

A further analysis of the transportation impact matrix was undertaken by arbitrarily increasing certain matrix entries, such as home computers, to evaluate the sensitivity of the "transportation world" to increasing automation• Three items were most effected by this increase• The need for transportation decreased, long distance commuting decreased and use and performance of StaRRcars increased. The first two events were intuitively expected, the third unexplained.[48]

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Richard Rochberg has done further work with the cross impact matrix method in connection with transportation forecasting. Rochberg considered the 72 transportation. events studied by Gordon and Hayward and attempted to define the matrix in terms of pivotal events.J49] A pivotal event is one which has the greatest impact on other events in the matrix. Rochberg used two separate measures of this. The first measure was intended to determine those events which, if they occur, would introduce the greatest degree ofcertainty or uncertainty about the future (as defined by the matrix). The major events in the matrix were found to be:[50] Introducing uncertainty • New materials for ultra light-weight construction • Increased use and performance of VTOL/STOL • Increased desire for convenience Introducing certainty • Increased use and performance of mass ACVs • Increased use and performance of autos • Society's need for transportation decreases The second measure was intended to determine those events which contain the greatest amount of information, without regard to whether they introduce certainty or uncertainty• These events were :[51 ] •Increased use and performance of autos • Increased desire for comfort • Increased desire for convenience • Increased desire for favorable environmental factors• The fact that the events selected by the technique used seem intuitively reasonable and the fact that two items appear on both lists gives Rochberg encouragement• There are a number of limitations to the cross impact matrix technique• Information derived from the analysis is, of course, no better than the information introduced into the matrix• If there are errors or improper assumptions in the data used, one would expect the same errors and improper assumptions to be reflected in the data coming out. Additionally, the expression used to calculate the cross impact is, at least to present, arbitrary• As Gordon and Hayward acknowledge, there is an " . . . uncertain accuracy of the P'vP (cross impact) relationship• The quadratic form was selected for convenience and because it intuitively appeared to have the proper s h a p e . . , other forms should be tested."[52] Perhaps a more serious limitation is the assumption of some causative relation among the elements, particularly if value changes are not included as elements in the matrix• That is, while the occurrence of one event may make another event more feasible technically, it is not intuitively obvious why the probability of the second event should increase if the event is constrained primarily by lack of public acceptance• In transportation, for example, if the concentration of the population is such that high speed trains will not receive wide usage, and this is the causative event, it is difficult to see how development of linear electric motors would increase the probability of high speed trains• Perhaps this is the same reservation raised as with the Delphi method.

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The evaluations are subjective. This does not mean that the Delphi or the cross matrix techniques are not interesting and useful. It simply means that they must be used with care.

Trend Extrapolation Trend extrapolation is the simplest form of forecasting which makes use of objective data. Basically one simply examines the past, to whatever depth seems appropriate; observes the trends; and projects those trends into the future. Trends may be either projected as a direct continuation of the past, or certain qualifying assumptions may be introduced to project trends which deviate from the past in some specified manner. Additionally, one may correlate a "family" of trends to project the growth in some functional area. One of the best known "family" extrapolations in the area of transportation is that of speed. Graphs showing the growth in speed of travel since the beginning of man appear in a number of publications. Ayres uses this example to illustrate the importance of choosing proper coordinates when extrapolating trends graphically. [53] Perhaps because of the wealth of numerical information in the field of transportation, trend extrapolation has found great favor among the forecasters in this field. A complete review of projections using this method is not possible, but several of the larger studies deserve mention. In 1963, Resources of the Future made projections of the adequacy of America's natural resources between the years 1960 and 2000. Transportation was one of the factors projected. This projection was made based upon the historical relationship of transportation and other factors of the economy, size of population, volume of production, etc.[54] Three levels of projection were made: high, median, and low, based upon the overall level of growth. The starting date was 1963. It is instructive to review some of the projections for 1970.

Total Stock of Personal Vehicles--1970

Actual--1968

Projections (millions)[55] L 81.0 M 83.3 H 91.0

84.0 (Source: Transportation Facts and

Revenue Passenger Miles by Mode--1970 Projections (billions)[56] Rail L 12.1 M 14.1 H 17.8 Bus L 15.8 M 19.1 H 22.3 Air L 60.6 M 66.6 H 75.8

Actual--1969 (est.)

Trends)

12.0 declining (Source: as above)

26.0 rising

102.0 rising

Thus at the end of only seven years, only one of these four major measures of transport is within the projected range.

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An earlier study conducted by Dewhurst and Associates employed similar techniques to predict the changes in transportation between 1950 and 1960.[57] The results were of approximately the same accuracy as the Resources for the Future study, except the Dewhurst projections were in more general terms. Dewhurst was correct in predicting increased auto and airline travel, but erred in predicting major improvements in and usage of urban mass transportation. Among the specific projections, a prediction of slight decline in rate of automobile ownership (to 59 million in 1960)[58] was not realized. The rate remained about constant and there were approximately 62 million autos registered in 1960.[59] Only in the past few years has the rate of increase shown any signs of tapering off. The most comprehensive projections related specifically to transportation were were prepared under the direction of A. H. Norling of United Research, Inc. under contract to NASA.J60] The basic purpose of the study was to determine areas where air transportation might be of growing importance. However, all modes of transportation were considered in great detail. Projections were made to the year 2000. The approach was similar to that adopted for the previously mentioned studies, except that transportation was related to a greater number of external factors. The overall growth factors considered were: demographic, economic, geographic, societal, political, and technological. Also incorporated into the analysis were the followingtransportation service and demand factors: class of traffic, type of movement, origin-destination characteristics, volume, distance, speed, value of service, reason for travel, convenience, and safety. Where possible, these factors were given numerical bases determined by past experience. Where an objective measure was not possible, subjective estimates were made. Separate forecasts were made for intra-urban, interurban, and international travel. The report is extremely impressive in the amount of data which has been incorporated into the estimates. In the final analysis, for most projections subjective factors were found which might increase or decrease historical trends and consequently the trends were simply projected directly. Considering the volume of data apparently included in the analysis, the results are disappointing. The following example is illustrative.

Projected Common Carrier Passenger Miles (Billions)[61 ] 1970 1980 1980

Air Surface Air Surface Air Surface

54 47* 91 52* 91 55*

Actual--1969 (est.) 102 increasing 42 declining (Source: Transportation

Facts and Trends)

* Adjusted to commondata base One would not expect that projections made on the basis of past trends would be exact, but the wide margin of error in the examples noted and the complete reversal of trends in some instances points clearly to the limitations of the trend extrapolation technique. In concentrating almost entirely on the past, other factors influencing transportation development are ignored. This brings to mind a criticism which Edward B. Roberts has made of exploratory forecasting (of which trend extrapolation is but

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one type). Roberts suggested that exploratory forecasting used very simple techniques to treat a wealth of data. Normative forecasting, which we shall consider momentarily, on the other hand, uses very elaborate techniques to treat a dearth of data.[62] Another difficulty of trend extrapolation, at least in its raw form, is that it assumes the external factors to be "fixed". For the purposes of planning, one is interested in knowing in what ways various levels of investment will affect the trends. Prehoda gives this brief attention. [63]

Normative Forecasth~g As mentioned in previous paragraphs, normative forecasting presumes that you know where it is that you would like to go and the forecast reveals how this destiny might be achieved. Some criticism of previous applications of this approach by Roberts have already been noted. Only one example, and it subsequent to the criticism, has been found which applies a normative approach to the whole of transportation. G. Bouladon has used the normative approach to identify future gaps in the transportation hierarchy. [64] Fundamental to Bouladon's approach is the assumption that " . . . the choice (of modes) depends . . . on total transport time. Time is our most previous possession."[65] From this assumption, a fundamental law linking time and distance is proposed and present modes of transportation plotted against the "desired" characteristics. By this method it is found that walking, the auto, and subsonic air transport are effective means of travel for certain distance blocks, but that other distance blocks are not served by an effective mode. The blocks which aren't served lie between walking and the auto, the auto and subsonic air, and above subsonic air. Only a continuous conveyor type system will be satisfactory for the first block. The second may be served by VTOL/STOL, high speed trains, or air cushion vehicles. Of course the upper block requires supersonic or hypersonic aircraft. Bouladon continues with the thesis that the ever increasing demand made by users for relatively faster travel over the same distance can be explained by the general rise in average income, because in his view people equate time with cost. Based on this presumption, the "transport function" which relates time to distance is seen as changing over time. Bouladon holds that such changes can be anticipated and his graphs suggest ways of accomplishing this. The approach used by Bouladon is very attractive. It fits the entire transportation system into a single, neat spectrum. Using time as the basis for calculations and equating cost with time also has a great deal of appeal for many. For example, John E. Gibson endorses such a view when he says,"I propose the following intuitive truth. It should take you a given lapsed time to go from 'here' to 'there', independent of the distance between 'here' and 'there'. And that elapsed time should not exceed 4 hours."[66] Gibson avoids cost considerations almost entirely, since he proposes that our goal might be to make all transportation free by the year 1985.[67] The only apparent deficiency is that the assumptions seemingly do not correspond to the facts. Travel decisions are, perhaps unfortunately, not made simply on the basis of time. There are a number of excellent surveys of the attitude of travelers. [68] Lansing, for example, lists three major headings which determine passenger preference: availability, financial considerations, and quality and preferences. [69] Norling rejects Bouladon's other assumption (cost may be equated with time) after a lengthy analysis, concluding, "The value placed upon time may vary widely by individual, and in many cases, that value may be zero."[70] Even though the immediate study may be questioned on several grounds, as a first step in use of the normative approach Bouladon has made a valuable contribution.

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Transportation Models Apparently with the advent of electronic computers transportation models have" enjoyed increasing popularity. There are numerous types of models for varying purposes. In general they are attempts to represent mathematically various segments of the transportation system. Although there is a great deal of literature on the subject, most of that reviewed deals with types of models and model formulation. Few attempt to apply the models to an actual situation although some trials have been made. As might be expected in a developing field, there is a great deal of criticism of the initial efforts. Martin Wohl, for example, faults most of the work involving transportation modeling for assuming the external variables such as technology and trip demand to be fixed. In reality, he argues, any change resulting from the model study may well affect these factors. The model should, therefore, be dynamic. That is, it should contain a feedback cycle which will place the factors in equilibrium.[71] Eugene Canty finds the techniques still somewhat primitive.[72] If one is concerned with technological forecasting as a major influence on transportation planning, or if one is concerned with R & D investment for transportation developments, James Quinn would deal modeling an even more serious blow. According to Quinn, mathematical formulations are almost worthless. The requisites are a knowledge of the scientific field under study, a real sense of the economic implications of the science, and imagination without star gazing.[73] Intuitively, however, there seems to be no innate reason why modeling would not be a useful tool if one understood all of the parameters involved. At least one effort has been made to raise mathematical modeling an order of magnitude above traditional network simulation. Peter Fielding reported in 1966 on A F T (Analysis of Functions of Transportation) which was then being undertaken for the Bureau of Public Roads. This was an attempt to model "the essential characteristics of U.S. t r a n s p o r t a t i o n . . . (thereby) answering overall transportation system problems."[74] No results of the analysis are given in the article and apparently these first efforts were less than a spectacular success since no further reference to the work appears in the literature. Little can be said about modeling as a general approach to transportation forecasting. It would seem to have some potential but the magnitude of the data required for any large scale analysis would be enormous. Unless the technique begins to grapple with some of the value problems and other major influencing factors it will likely be confined to examining transportation flow in limited areas and even then be of questionable service.

Transportation Planning This is really a nebulous category intended to include those few efforts designed to incorporate transportation forecasting into the planning process. Each of the studies listed under this heading is concerned witha limited sector of the transportation problem, either geographically, modally, or conceptually. Because of their limited scope the studies will not be treated in detail. Rather, we shall be concerned only with the techniques employed. A comprehensive, six-year study was undertaken by the Port of New York Authority to determine transportation needs of that area in the year 1980.[75] In this study, transportation was considered but one component of the entire economic system of the area.[76] Transportation was considered in relation to population change, economic growth, population distribution, and similar factors. Potential technological changes are discussed at some length in the report, but as far as can be determined were not

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incorporated into the projections. The actual basis of the projections is not entirely clear but it appears to be primarily trend extrapolation of presumed transportation determinants. Even with an analysis as comprehensive as this one, it is stated that, "The report does not presume to set forth a program outlining the transportation facilities that the region will require by the year 1980."[77] Since this study required six years one wonders how long would be required for such a program to be developed. Similar studies have been conducted for other regions, including the TALUS study for Detroit and the Bay Area Transportation Study for San Francisco. [78] In the case of the TALUS study, "The heart of the planning process is a series of mathematical models which express relationships between variables and permit us to describe the region in synthetic terms and predict the effect of alternative plans on development of the region."[79] A study of freight transportation in the year 2000 in the Great Lakes area has also been completed. Again, this is based primarily upon extrapolation of trends.[80] With regard to modal projections, aviation has received the most attention. The Federal Aviation Agency issues periodic ten-year forecasts.[81] The basis of these forecasts are not readily apparent. Attention has also been given to national aviation goals.[82] This report is notable for the lack of attention which it devotes to other means of transportation. A. E. Raymond sees aviation at a cross roads of decision where further development may either be aimed at increasing speed or increasing capacity and reducing cost.[83] Of the two, he suggests adopting the latter. Finally, Norman Asher, et al., have predicted the demand for supersonic transportation, based upon population, per capita income, fares, and trip times.[84] They conclude that an SST is economically desirable. There have been two major conceptually oriented problem studies. The first is the Northeast corridor project, which resulted, among other things, in the institution of high speed train service between New York and Washington. Studies involved in this project have not been reviewed in detail although the literature contains considerable information. [85] The second extensive series of studies was aimed at ameliorating the growing urban transportation problem. This program was begun under the direction of the U.S. Department of Housing and Urban Development before this activity became assigned to the U.S. Department of Transportation. Contracts for various aspects of the study, including goals, technological development and transportation modeling, were given to a number of research establishments. The resulting reports contain an enormous amount of information applicable to all levels of transportation.[86] The results of these studies were digested and incorporated into a single volume, Tomorrow's Transportation. [87] Future systems recommended by this report are: dial-a-bus systems (demand activated bus systems); personal rapid transit (private vehicles operating on exclusive guideways); dual mode vehicle systems (private vehicles capable of operating on a street or an automated network); automated dual mode bus (similar to the previously described system, except for large capacity vehicles); pallet or ferry systems (car carrying trains); fast intra-urban transit lines; and systems for major activity centers (moving belts, capsule transit, or network cab transit).[88] The action program recommended by the study is to undertake research and development projects (the Federal role) intended as a major guiding stimulus to solution of urban transportation problems. The composite of the program, which includes much more than future systems, is intended to achieve eight transportation objectives enumerated in the report.j89]

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Techniques and projections used in development of the various action plans are almost as numerous as the plans themselves. One feature seemingly common to all of: the plans is that they are based upon the analysis of those in the planning cycle. Only a single final plan, if any, is recommended. This would satisfy B. A. Schriever who suggests that transportation planning is rather like planning for other physical subsystems such as water and sewage. [90] The wishes of the populace should be taken into account, but they should not participate directly in the planning process, where they can contribute little. C. A. O'Flaherty places the emphasis in a different context in observing, "All (engineers, planners, etc.) must accept that their function is not to tell members of the public what is good for them but rather to interpret their wishes and desires and to help provide those which represent social progress."[91 ] Hans Heymann, Jr. goes even further to say that the role of the planner is to clarify the trade-offs among the objectives, that is, "How much of one goal might we be willing to trade offto obtain more of another?"[92] According to Heymann the planner has no magic to resolve this question and yet he has never seen a plan which represents a range of alternatives for public discussion.[93] After a brief review of the literature it appears that Heymann's observation is still valid. While it is possible to sympathize with Schriever in his view that people get in the way of an efficient planning process, it must also be recognized that if we are serious about the business of shaping our future some means must be found to include effective public input of goals and objectives: not present goals and objectives, but those that are anticipated in the future. Such a process would take a lot of adjustment on the part of both the public and planners; it is, however, realizable. This does not necessarily mean a popular election for each plan; most of the public would not even be interested. It does mean an,opportunity for those groups which are interested to see the anticipated results of alternatives decisions and to express their views.

Evaluation Techniques Discussion of a selection among alternatives leads directly to consideration of means by which those alternatives might be evaluated. The most common method for doing this is cost-benefit analysis, in which the direct and indirect costs and benefits of each alternative are measured. This then is used as a basis for selection, the alternative with the greatest cost/benefit generally being accepted. First use of such analysis for government projects was probably made by the Army Corps of Engineers. It later became popular with the Defense Department and has since become partially incorporated into the government wide PPBS. Greater use of this technique for evaluating transportation alternatives has been suggested by a number of writers, among them William D. Franklin,[94] Eugene Canty,[95[ and Martin Wohl.[96] Others, such as H. W. Bruck have endorsed the general idea, Bruck by holding that we need better methods of evaluation, particularly of weighing factors such as flexibility.[97] The method is not without its critics, one of whom contends that had cost-benefit analysis been employed, the railroads would never have been built.[98] It is presumed that the critic assumes the present railroad system to be a social blessing. Some analysis technique is undoubtedly required if one is to compare alternatives and it seems that the cost-benefit method is as good as any other, presuming that the factors included in the analysis and the relative weighing of these factors is made explicit, and preferably subject to the same public scrutiny as the alternative plans. There are, however, other evaluation techniques, as will be observed shortly.

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Social Impact Perhaps a better title for this section, since it follows a commentary on cost-benefit analysis, would be social benefit. Whatever the name, some effort has been made to develop a system whereby the social impact of new developments might be evaluated. Two recent studies[99] have employed the Delphi technique for obtaining such estimates An earlier work[100] used a simple polling technique to the same end. One of the later studies, conducted by Gordon and Ament, was discussed during examination of the Delphi technique in a preceding section. It will be recalled that the mean date of occurrence for four transportation events was predicted by a Delphi panel of experts. Next the experts were asked to evaluate how likely it is that occurrence of the event would cause each of several tabulated consequences. Finally, the experts were asked whether these consequences would, in their view, be favorable, unfavorable, or neutral. The table on page 385 lists results of selected predictions. This approach seems a possibly powerful tool for helping to determine which among a multitude of transportation alternatives are most worthy of more detailed evaluation.

Other Possible Techniques A number of transportation forecasting techniques have been examined. It has been noted that these techniques tend to focus upon the projection of the past or to unduly simplify the transportation future. What is really required, if one is to shape the future, is a system that allows integration of some future goals into some present framework. There are some additional techniques which have been used for other purposes which deserve consideration for possible use in transportation. Marvin Cetron describes one technique which has found some application in evaluating U.S. Navy research and development projects.[101 ] This is an integrated system which begins with a statement of national policy, a state of the art technology forecast, and the present environment. These statements are then translated into an estimate of wants, present capabilities and resources, or a needs and deficiencies analysis conducted. The results of this are measured against expressed national goals and if necessary recycled from the beginning. Once the statements are compatible with national goals, the task is further broken down into technical objectives and eventually an R & D program. Most of this process is carried out by computer program. [102] The weakness of the system, if there is one, is in the subjective determination of national goals and wants and in their translation to sub-objectives. Ayres discusses this possible flaw in connection with a similar program P A T T E R N (Planning Assistance Through Technical Evaluation of Relevance Numbers), a system developed for use by military planners. On the first breakdown from national objectives to three sub-objectives, the planners assigned relative weights to the factors which were apparently far from the actual weighting given to the factors by the President in subsequent actions.[103] A similar technique, PROBE II is being refined for industrial use. The PROBE system relies upon the Delphi technique to translate goals into actual R & D planning.[104] Donald L. Pyke suggests that the various categories of forecasts should not be considered mutually exclusive, but that a whole range of forecasts should be applied to each attempt to determine long-range impact.J105] The categories of techniques which Pyke suggests, together with some examples of each category are as follows :[I06] Extrapolative techniques: trend analysis, trend correlation, scenario construction Speculative techniques: morphological analysis, conjecture (experts, Delphi) Explicative techniques: relevance trees, logic networks

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Correlative techniques: mapping, cross impact matrix, input-output Selective techniques: relevance trees, cost benefit, model simulation, decision theory, systems analysis This is simply a logical breakdown of the integrated systems described in the preceding paragraph, but it is helpful to consider each set of actions in discrete segments so that the results of each segment, and the effect of varying the parameters Of that segment might be readily determined. It is noteworthy that few have appeared in the review of transportation forecasting. Toward a New Technique

Several factors influencing transportation forecasting have been identified. These are the process of innovation, the relationship among factors influencing change, the context of transportation history and current transportation patterns. In reviewing various forecasting techniques it has been observed that they tend to concentrate on extrapolation of the past and ignore innovation, or upon innovation and ignore the past. It has also been seen that one needs to take account of expected travel preferences, and that ideally it is desirable to present a range of possible transportation alternatives together with their projected effects. Finally, some possible integrative methods for accomplishing these ends were noted. It seems to this writer that a successful forecast must start with both clearly defined objectives and techniques suitable to the time frame of the forecast. As we noted previously, beyond a time frame of, say, 5-7 years use of extrapolative techniques becomes very tenuous. At the same time, normative techniques may oversimplify the end objectives of the forecast. Additionally, in all likelihood, normative forecasts underly and probably inadvertently reflect the value system of the forecaster. Between these two limitations lies the dilemma of the forecaster. The short-range (5-7 year) forecast represents, in effect, what already is. Society and its institutions have already made the decisions and allocated the funds which will determine the short-range future. Major changes in this future are unlikely, and extrapolation of the past can be undertaken with a reasonable degree of confidence. Once it is attempted to forecast the future beyond the short range, one must deal increasingly with societal decisions. Long-range planning for major systems, such as transportation, are concerned primarily with societal decisions. This is apparently not recognized by most long-range forecasts. Traditionally, long-range forecasting techniques have assumed that experts make the best forecasters Even when expert opinions are combined so that a future-consensus is reached, it is virtually impossible to take account of societal decisions. Even when it is possible, basic assumptions are made about what decisions society should make. It seems to this writer that for the purposes of long-range planning the expert has been misplaced in the forecasting system. The role of the expert should be an enabler rather than one who unilaterally "casts" the future or even decides its parameters. That is, the future is a series of events to be created by a combination of forecasts and plans, not something which is created solely by the past or the vision of forecasters. If this is so, and it certainly must be if we assume that the future is ours for the shaping, then long-range forecasting must consist of a combination of both normative and exploratory forecasts. Further, it is possible to use normative forecasting techniques to establish the long-range objectives which society seeks to achieve. 26

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Forecasting methods presently used are suitable for this purpose if they are imaginatively employed. For example, it is proposed that Delphi techniques would be more useful if they employed lay participants rather than experts. These participants, through the usual Delphi feedback system, would agree upon a balance of normative objectives which society should work toward in some future year, say 2000. In effect, through the Delphi panel, a future quality of life would be defined in terms of its major parameters (security, health, etc.). A consensus on the relative importance of these parameters would be reached. Further, the lay participants could be asked to evaluate and agree upon the positive or negative impact which potential transportation developments (e.g., increased speed) might have on the possible achievement of these objectives. Thus, lay participants would define the forecasting and planning parameters for the expert. Experts would evaluate these agreed objectives and potential impacts in light of potential short-range transportation innovations and develop a series of alternative transportation "futures". These futures, which would be based upon the present mix of transportation systems, would then be evaluated by the Delphi lay participants to determine how well each alternative meets the previously agreed normative objectives. Through this process it should be possible to determine which potential transportation developments are most likely to create the future transportation system desired by society, as defined by the Delphi panel. This information would then be used as an input to the traditional decision-making processes involving all of society's institutions. This technique requires some exploration to determine its practicality, but there are no immediately apparent reasons to believe that it would not be viable. It is not to be expected that a Delphi consensus, no matter how representative the participants, will exactly represent that of society. The panel, however, is only an expediency--society makes the final choice. Assuming its practicality, the technique overcomes many disadvantages of past techniques. It marries normative forecasting, which permits channeling transportation developments to desired societal objectives, to exploratory forecasts, which reflect the present and the past. It also establishes the expert in a role of advisor and enabler, rather than predictor--a role which could never be fully realized without a great deal of unintended subjective valuations. It also recognizes that man is fully in charge of using technology to his own ends, and not the converse. Finally, through the use of Delphi consensus techniques to define societal objectives and through attempts to measure alternative transportation futures against these objectives, one is confronted with the painful but necessary compromises which must be resolved before progress is possible. It is only through a technique such as this that the usefulness of transportation forecasting will be fully realized.

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385

Table

Value Impact of Possible Transportation Developments (Adapted from T. J. Gordon & Robert H. Ament, Forecasts o f Some Technological and Scientific Developments and Their Societal Consequences) Predicted Year I

Potential Development Widespread existence of regional high-speed transportation systems such as VTOL/STOL, GEM, 200 mph trains and so on.

Widespread use of automobile engines, fuels or accessories which permit operation without harmful exhaust

Widespread use of surface effects ships for ocean transport

Routine use of reuseable ballistic suborbital transports for military or commercial passenger and cargo transportation

1990

1980

2000

2010

Potential Effect

Likelihood z Consequence 2

Dispersion of cities

3

4

Great increases in in congestion in major urban cities

2

2

Increase in air traftic control problems

3

2

Increased traffic congestion

3

2

Delay in developmen t o f high-speed transport

2

3

Continued economic domination of automobile industry

3

3

Diminished for canals

need

2

4

Effective, desirable passenger transport at distances up to 100 miles

3

4

A smaller world, at least to some people.

2

4

The development of anti- ballistic rocket techniques by countries which wish to deny landing sites to these vehicles

2

3

i Mean year of predictions for 50 ~o probability of occurrence of development 2 Scales:

Likelihood

Consequences

4--Very certain 3--Probable 2--Possible l - - A l m o s t impossible

5--Very favorable 4---Favorable 3--Little or no importance 2--Detrimental I--Very detrimental

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References I Transportation Association of America, Transportation Facts and Trends, Seventh Edition, Washington, D.C. (1970), p. 3. 2 Harmer E. Davis, "Urban Transportation Planning--lntroduction to Methodology", in Defining Transportation Requirements, ASME, New York (1968), p. 10. 3 Melvin Kranzberg, "The Social Impact of Transportation Technology: Some Lessons of History" in Essays on Transportation Problems hi the 1970s (George Smerk, Ed.), Bureau of Business Research, Indiana University, Bloomington, Ind., pp. 4-35. 4 There are numerous examples of such speculation. Two typical ones are: Frederick C. Appel, "The Coming Revolution in Transportation", National Geographic 136, 301 (1969) and Arthur Clarke, Profiles of the Fature, Bantam Books, New York (1963). 5 See, as examples, Robert U. Ayres, Technological Forecasthtg and Long-Range Plannhtg, McGrawHill Book Company, New York, (1969) and Robert W. Prehoda, Designing the Future, Chilton Book Company, New York (1967). 6 Emmanuel G. Mesthene, "The Impact of Science on Public Policy", Public Admhlistration Review 27, 97 (1967). 7 Peter F. Drucker, Technology, Management and SocieO,, Harper and Row, New York, (1970), p. 5. 8 Davis, op. cit., p. 10. 9 Sumner Myers and Donald G. Marquis, Successful Industrial Innovations, National Science Foundation, Washington, D.C. (1969), p. 31. 10 Lester A. Hoel, "'Transportation Technology and Systems Planning", Traffic Quarterly 22, 167 (1968). I I Elting Morison, "A Case Study in Innovation", in Research, Derelopment and Technology hmoration (James R. Bright, Ed.), Richard D. Irwin, Inc., Homewood, I11. (1964), pp. 100-115. 12 James M. Utterback, "The Process of Innovation: A Review of Some Recent Findings", paper presented at Conference on Technological Forecasting: Concepts and Methods, June, 1968. 13 As examples see Myers, op. cit., p. 38 and Utterback, op. tit., p. 11. 14 As examples see Myers, op. cit., p. 38 and Willard J. Mueller, "Origins of DuPont's Major Innovations, 1920-1955" in Research, Development and Technological Innovation (James R. Bright, Ed.), Richard D. Irwin, Inc., Homewood, III. (1964), pp. 383--401. 15 W. L. Garrison, "Innovation of New Transportation Systems", in (Ref. 2) Definhtg Transportation Requirements, pp. 4-8. 16 Utterback, op. cit., p. 4. 17 Dale E. McDaniel, (1971, unpublished), p. 26. 18 Seymour Dunbar, Histot3, of Travel #~ America, Bobbs-Merrill, Indianapolis (1915). 19 Ibid., p. 231. 20 Oscar Osborn Winther, Tire Transportation Frontier: Trans-Mississippi West 1865-1890, Holt, Rinehart, and Winston, New York (1964). 21 Morison, op. cir. 22 Hans Heymann, Jr., Transport Technology and the Real World, Rand Paper P-2755, Rand Corp., Santa Monica, California (1963), p. 8. 23 Erich Jantsch, Technological Forecasting #t Perspectire, OECD, Paris (1967), p. 31. 24 Ayres, op. cir. 25 Arthur P. Lein, Paul Anton, and Joseph W. Duncan, Technological Forecasthrg: Tools, Techniques and Applications, AM A Management Bulletin No. 115 (1968), p. 17. 26 C. A. O'Flaherty, Passenger Transport Present and Future, Leeds University Press, London (1969), p. 34. 27 Ibid., p. 36. 28 Ibid., pp. 39-57. 29 Ibid., p. 53. 30 Ibid., p. 61. 31 John B. Rae, "Transportation Technology and the Problems of the City", Traffic Quarterly 22, 299 (1968). 32 John E. Gibson, "National Goals in Transportation", IEEE Proceedings 56, 380, 384 (1968). 33 Ibid., p. 383. 34 Hal Hellman, Transportation in the Worm of the Future, M. Evans and Company, New York (1968). 35 Putnam Beckwith, Tire Next 500 Years, Exposition Press, New York (1967), p. 33. 36 Prehoda, op. cit., pp. 158-163. 37 Ibid., p. 163. 38 For example, see M. A. Sulkin, et, al., Frontiers o f Technology Study, North American Rockwell Corporation, Los Angeles (1968), Vol. I-III.

T R A N S P O R T A T I O N FORECASTING: A REVIEW 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68

69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84

387

Clarke, op. cit., p. 24. Ibid., pp. 39-40. Ibid., p. 59. Ibid., pp. 70-81. Ibid., p. 81. T. J. Gordon and Robert H. Ament, Forecasts of Some Technological and Scientific Developments and Their Social Consequences, Institute of the Future, Middletown, Conn. (1969). T. J. Gordon and H. Heyward, "Initial Experiments With the Cross Impact Matrix Method of Forecasting", Futures 1,100 (1968). For example, see Ayres, op. cit., pp. 18-2g. Gordon and Heyward, op. cit., p. 100. Ibid.,p. ll4. Richard Rochberg, "Information Theory, Cross-Impact Matrices, and Pivotal Events," TechnoL Forecasting 2, 53 (1970). Ibid., p. 59. Ibid., p. 60. Gordon and Heyward, op. cit., p. 115. Ayres, op. cit., p. 21. Hans H. Landsberg, Leonard L. Fischman, and Joseph L. Fisher, Resources in America's Future: Patterns o f Requirements and Availabilities 1960-2000, Johns Hopkins Press, Baltimore (1963), p. 128. Ibid., p. 641. Ibid., p. 648. J. Frederick Dewhurst and Associates, America's Needs and Resources, The Twentieth Century Fund, New York (1955). Ibid., p. 292. Transportation Association of America, op. cit., p. 30. A. H. Norling, Future U.S. Transportation Needs, United Research, Inc., Cambridge, Mass. (1963). Ibid., p. VI-63. EdwardB. Roberts,"Exploratory ForecastingandNormativeForecasting:ACriticalAppraisal", in Research, Development and Technological hmovation (Ref. 11), pp. 245-261. Prehoda, op. cit., p. 22 G. Bouladon, "Technological Forecasting Applied to Transport", Futures 2, 15 (1970). Ibid., p. 17. Gibson, op. cit., p. 381. Ibid., p. 380. For two examples, see John B. Lansing and Dwight M. Blood, The Changing Travel Market, Braun-Brumfield, Inc., Ann Arbor (1964), and Robert K. McMillan and Henry Assel, National Survey o f Transportation Attitudes and Behavior (Report No. 49), Highway Research Board, National Academy of Science, Wash., D.C. (I 968). Lansing, op. cit., p. 41. Norling, op. cit., p. VI--44. Martin Wohl, "Another View of Transport Systems Analysis", in IEEEProceedings 56, 446 (1968). Eugene T. Canty, "Future Transportation Systems Study", Traffic Quarterly 22, 3 (1968). James Brian Quinn, "Top Management Guide for Research Planning", in Research, Development and Technological hmovation, (Ref. I I ), pp. 677-700. Peter G. Fielding, "DevelopingTransportation Systems Analysis as a Basis for Policy Guidelines", in 1966 National Transportation Symposium ASME, New York (1966), pp. 83-96 The Port of New York Authority, Comprehensive Planning Office, Metropolitan Transportation-1980, New York (1963). Ibid., p. 4. IBM., p, vii. Commentaries on the Detroit and San Francisco studies are contained in Irving J. Rubin, "TALUS: The Detroit Regional Transportation and Land Use Study", pp. 424-434, and John C. Beckett, "The Bay Area Transportation Study", pp. 435-473, respectively in IEEE Proceedings 56 (1968). Rubin, op. cit., p. 427. Sir James Easton, Transportation o f Freight in the Year" 2000, Great Lakes Area Trade Development, The Detroit Edison Company, Detroit (1970). Federal Aviation Agency, Aviation Forecasts, Fiscal Years 1967-1977, Wash., D.C. (1967). Federa• A viati•n Agency• Rep•rt •f the Task F•rce •n Nati•nal Aviati•n G•als• Wash.•D.C.( • 96• ). A. E. Raymond, Over" the Horizon in Air Transportation, Rand Paper P-3396, Rand Corporation, Santa Monica, Calif. (1966). Norman Asher, William F. Blazer, William A. Cox, Richard F. Muth, and Walter Oi, Demand Analysis for Air Travel by Supersonic Transport, Institute for Defense Analysis (1966).

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85 For example see Robert J. Hansen, "Planning for High Speed Ground Transportation", pp. 472-486 and George R. Herbert, "High Speed Ground Transportation--A Research Challenge", pp. 487-492 in 1EEE Proceedings 56, (I 968). 86 There were a number of individual studies connected with the project. Those most relevant to technological development and transportation objectives are Consad Research Corporation, Transit Usage Forecasting Techniques: A Review and New Dh'ections, Consad Research Corporation, Pittsburgh, Penn. (1968), Stanford Research Institute, Future Transportation Systems: Desired Characteristics and Future Transportation Systems: Technological Assessment, Stanford Research Institute, Menlo Park, Calif. (1967); and M. A. Sulkin, et. al., Frontiers of Technological Study (Ref. 38). 87 U.S. Department of Housing and Urban Development, Tomorrow's Transportation, Wash., D.C. (1968). 88 Ibid., p. 58-77. 89 Ibid., p. 79. 90 B. A. Schriever, "The Critical Path in Planning" in Definhag Transportation Reqtdrements, ASME, New York (1969), pp. 1-3. 91 O'Flaherty, op. cit., p. 71. 92 Heymann, op. cit., p. 10. 93 Ibid., p. 9. 94 William D. Franklin, "Benefit-Cost Analysis in Transportation: The Economic Rationale of Resource Allocation", Traffic Quarterly 22, 69 (1968). 95 Canty, op. cit., pp. 3-17. 96 Martin Wohl, "Transportation Concepts and Issues", in 1966 Transportation Symposium, ASME, New York (1966), pp. 71-78. 97 H.W. Bruck, "Problems of Planning for the Future", in 1966 Transportation Symposium (Ref. 96), pp. 79-82. 98 Edward N. Hall, "Transportation in Technically Developed Societies", 10th Israel Conference on Aviation and Astronautics, Tel-Aviv (1968); Federal Clearinghouse for Scientific and Technical Information, No. N68-29529. 99 Raul de Brigard and Olaf Helmer, Some Potential Societal Developments--1970-2000, Institute for the Future, Middletown, Conn. (1970), and T. J. Gordon and Robert H. Ament, Forecasts of Some Technologicaland Scientific Developments and Theh" Societal Consequences (Ref. 44). 100 Nicholas Rescher, "A Questionnaire Study of American Values by 2000 A.D.", in Values and the Future Baier & Rescher (Eds.), The Free Press, New York (1969), pp. 135-147. 101 Marvin J. Cetron, "A Method for Integrating Goals and Technological Forecasting into Planning", Technol. Forecasting 2, 23 (1970). 102 Ibid., p. 30. 103 Ayres, op. cit., p. 172. 104 Harper Q. North and Donald K. Pyke, "Technological Forecasting to Aid R & D Planning", Proceedings of the Twenty-Second National Conference on the Administration of Research (1968), pp. 59-69. 105 Donald K. Pyke, "Technological Forecasting: A Framework for Consideration", Futures 2, 327 (1970). 106 Ibid., p. 381.

Additional Bibliography Boorer, N. W., "The Future of Civil Aviation", Futures 1, 206 (1969). Boyd, Alan S., "The United States Department of Transportation," IEEE Proceedings 56, 396 (1968). Breur, Robert and Schafer, J. H., "Transit Evaluation, Demand and Nondemand Aspects", in Defining Transportation Requh'ements, ASME, New York (1969), pp. 24-32. Brigham, Georges, "Transportation Tomorrow", Science and Technology, 86, 50 (1969). Enzer, Selwyn, "A case Study Using Forecasting as a Decision-Making Aid", Futures, 2, 341-362 (1970). Gilifillan, S. Colum, "The Prediction of Technological Change", in James R. Bright, Research,Development and Technological Innovation, Richard D. Irwin, Inc., Homewood, III. (1964), pp. 738-754. Klein, George E., "Evaluation of New Transportation Systems" in Defining Transportation Systems Requirements, ASME, New York (1969), pp. 70-82. McHale, John, The Future of the Future, George Braziller, New York (1969) Miller, James R., III, Assessing Alternative Transportation Systems, Rand Memorandum RM-5685DOT, Rand Corporation, Santa Monica, Calif. (1969). Nelson, Richard R., Merton, J. Peck, and Kalachek, Edward D., Technology, Economic Growth and Public Policy, The Brookings Institution, Wash., D.C. (1967).

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Richards, Brian, "Urban Transportation and City Form", Futures 1,239 (1969). Sarnoff, David, "By the End of the Twentieth Century", Fortune 64, 116 (1964). Schon, Donald A., Technology and Change, Delta, New York (I 967). Seifert, William W., "The Status of Transportation", IEEE Proceedings 56, 385 (1968). Simms, Richard, "Role of Technological Forecasting in Transportation", Defining Transportation Requirements, ASME, New York (1969), pp. 145-152. Turoff, Murray, "The Design of a Policy Delphi," Technol. Forecasting 2, 149 (1970). Wohl, Martin, "Thinking Out Loud About the Ground Transportation Problem", in Aviation andthe Nation: Measuring the Challenge of a Changing World, Connecticut General Life Insurance Company Hartford, Conn. (1967).