J. Edward Anderson

Department of Mechanical Engineering

University of Minnesota

September 23, 1970




Opinions expressed in this paper are those of the author and do not necessarily reflect collective opinions of any group.



            The Greeks had a philosophy they identified as “The Golden Mean.”  In one sense or another, too little or too much of anything was harmful.  In whatever he did, the wise man strove for the right balance – The Golden Mean.  Today, this ancient philosophy finds its expression in the term “optimum solution.”


            A prime example of a solution to a problem gone far beyond the optimum, away from The Golden Mean, is the automobile as a means of urban transportation.  Unfortunately, indications are that this solution will be carried much further yet from optimum at great expense to urban dwellers before it is forced into a sensible balance with other solutions – other transportation modes.  This is happening because we have no effective built-in mechanisms to seek and maintain optimum solutions to urban problems.  Forces for continuing present trends for the economic benefit of a few at the expense of the public as a whole are powerful.  In key decision-making processes at all levels of government, these forces have held sway over the forces of constructive change.  In urban transportation, as well as in other problems, we are being driven further and further from The Golden Mean.  Without a very considerable increase in the forces of change, the consequence of our dependence upon the automobile in urban life many be the stagnation and death of our central cities. 


            The current literature is replete with examples of the ill effects of the automobile.  Economically, billions of dollars each year are squandered because high-priced businessmen have to crawl through traffic to jobs, appointments, airports, etc.; because trucks get bogged down in downtown traffic; because potential shoppers just don’t make the trip downtown.  Millions of thankless hours are consumed by mothers locked into the task of children’s chauffer.  While attending school, young people are forced to work long hours just to maintain their automobiles.  Streets are designed with no thought to anything but auto traffic so that kids have few places to ride their bicycles and cause their parents endless worry as they walk to school, if there even is a place to walk.  Old people drive long after they should.  Even though drunks cause over half the 50,000 yearly auto deaths, judges fail to revoke their licenses because that would remove their means of access to the job.  The poor, who we think of once in a while, are simply left out of many opportunities.  More or less unwittingly, “the system” has forced almost everyone who can drive into an automobile.


            Valuable land is taken off urban tax rolls to build urban freeways, communities are divided, neighborhoods are uprooted, and residents are subject to tiresome freeway noise.  Parking lots require so much expensive land in the major activity centers that it has become economical to construct huge parking garages at a cost per space comparable to the cost of the auto itself.


            Urban man drives to his job, usually by himself, in a 7 x 17 foot sheet-metal monster that rarely travels over ten miles per gallon of gasoline and is so fragile it is extensively damaged in a collision over two miles an hour, thus skyrocketing insurance costs.  He struggles to maneuver his oversized machine into a parking space where it occupies valuable land and where it rests idle all day long.  The vast squandering of nonrenewable resources in metals and oil implied by such an inefficient means of transportation is now only perceptibly being recognized.  We operate as if there were no tomorrow.


            The fact that the automobile is by far the major urban air polluter has been recognized for some time.  People who were caught in the thermal inversion on the East Coast early this summer know what it means to be without fresh air.  But at the same time the American is bound economically, socially, and in many cases psychologically to his automobile and he is powerless by himself to bring about effective change.


            The huge corporations that make up the auto industry will not make significant changes until they have no alternative.  For example, it may be that oil could be sold in large quantities for something besides motor fuel (say, for making plastics); but the huge investment in gasoline cracking plants, distribution systems, and service stations is highly specialized and would represent an immense economic loss if the demand for gasoline subsided.  Automobile companies depend for their profits on production of large and increasing quantities.  If these profits decrease, stockholders no longer get the high return they expected, and as a consequence they sell their stocks.  This depresses the value of the stock, which is usually held in large amounts by corporate executives. Thus, these men have a strong personal interest in maintaining the system.  The auto industry produces 22,000 cars a day now and expects to be up to 41,000 cars a day by 1980.  They are supported by manufactures of tires, carburetors, generators, spark plugs, and hundreds of other specialized items.  All of these companies, all of the retail dealers and the service garages would fear a significant economic pinch if anything occurred to substantially reduce the demand for automobiles.


            Vast establishments led by the Federal Highway Administration are involved in furthering the construction of roads; and, of course, the road construction industry feels dependent for its survival on the planning of more and more of these roads.  The system perpetuates itself by means of trust funds supported by gasoline taxes; which, short of changing State Constitutions, can be used only for roads.  We are locked on a course that is steadily eroding the quality of life in our cities.    


            Up to a point, the automobile and its support system was close to an optimum solution to the problem of mobility, at least for those who could drive.  Now, however, in the larger cities of the United States, the auto is assuming the characteristics of a Frankenstein monster.  We feel uncomfortable, many of us, about building more roads, more cars, and selling more gasoline. On the other hand, the system for providing all of these things has been institutionalized to perpetuate itself.  Substantial changes are now very difficult politically since they will require real or perceived adjustments on the part of millions of people.


            What can be done?  How can environmental disaster be avoided?  Can it be avoided without producing economic disaster?  Let’s look at some of the things that are being tried.  We can show that most of these are feeble attempts – ineffective nibblings at the core of the problem.


            First, because of the problem of pollution from auto exhausts, the need to replace the internal combustion engine is urgent.  “Fixes” for these engines work well, unfortunately, only when the engines are new. The potential gains will be wiped out by increasing numbers.  Nothing at all is done this way to relieve the problem of congestion or the requirement for more and more parking garages.     


            Alternate modes of transportation need to be introduced.  Most cities turn to the bus.  The bus is a stopgap to provide badly needed transportation for those who cannot or do not wish to drive.  It could reduce congestion if people were coerced in large numbers to ride it.  While we may come to this by default at the expense of a considerable reduction in the quality of life, under present circumstances most people, as long as they can choose freely, will choose the private auto.  The bus stops and starts many times giving a slow, tedious, often nauseating ride.  It is second-class transportation no matter how many embellishments are added.   In addition, it pollutes the air, it mixes with street traffic, and it adds to congestion.  The bus is no threat to the auto industry. 


            Because of the inherently poor image of bus service, transportation consultants propose conventional rail systems on exclusive rights-of-way, i.e., metros or subways.  By placing the stations one to two miles apart, average speeds up to about 40 mph can be obtained, but at the price of limited access.  A cross-town trip is still a tedious stop-start journey.  The capacity of these systems is very high – up to 60,000 people per hour, but unfortunately, so is the cost – on the average about $20,000,000 per mile.  As a comparison urban freeways can carry a maximum of about 2000 cars per hour per lane and cost from about $5,000,000 to $30,000,000 per mile. 


            New York City is the only urban area in the United States in which the population density is high enough to justify conventional rail transit.  To make it economically sound elsewhere would require forced incentives to live in high-rise apartments near the stations.  Short of this, conventional rail reminds one of shooting rabbits with an elephant gun.  These systems are simply too expensive for the level of patronage they can attract.  If enough lines were built in the average United States metropolitan area to get people where they wanted to go, the cost would be way beyond reason, the disruption would be equal to that of installing freeways, and the patronage would be way below capacity.  As a result, the number of miles of lines usually proposed is so small that an insignificant percentage of the population can make use of the systems. For reasons like this, bond issues for rail transit have failed recently in Los Angeles, Atlanta, and Seattle.  Rail transit is no threat to the auto industry.


            Notwithstanding or perhaps because of the ineffectiveness of conventional hardware to serve the real transportation needs of the urban dweller, the vast majority of the funds in the Mass Transit Bill currently under discussion in the Congress are earmarked for conventional hardware.  Even in the case of research and training grants awarded by the Department of Transportation to major universities, the emphasis is to be place on training, not on research.  Without research, of course, most of the training will have to relate to conventional transportation modes.


            Just as the saddle shops of yesteryear were threatened by the horseless carriage, effective solutions to public transportation in urban areas will be perceived as a threat to the existence of the auto and associated industries in their present forms.  Effective solutions are in advanced states of development in many places in the United States, and their developers have many, many stories to tell about the very strong, often irrational resistance from people associated with the conventional transportation industry.  Before discussing these new solutions, it is important to stress that as a mater of policy their deployment should be required to proceed sufficiently gradually so that necessary economic and social adjustments can be made.  A transition to more efficient forms of transportation will, however, free a significant portion of individual income for other uses. By thus freeing a part of man’s burdens, the introduction of new-concept transportation systems would seem to inaugurate a new era in the history of transportation development.  In a free market, what is more economical will be inevitable.  In today’s climate, “more economical” must, of course, include externalities, i.e., indirect social costs.


            A solution to the problem of urban transportation will have to bring about a substantial reduction in the level of air pollution, decrease congestion, minimize direct land use for transportation facilities, avoid disrupting and dividing communities, be fast, convenient, and comfortable enough to attract riders away from their automobiles in significant numbers, and it must be reasonable in cost.  Technology exists today to build systems that will meet these requirements.  It is available as a result of advances in control theory and practice, digital computers, reliability of components, failure analysis, and systems analysis.  Primarily, it is available because a small number of capable inventors envisioned the need some years ago and developed their ideas to the point where their systems can now be ordered and installed within a period of two years.


            The idea is as follows:  To compete with the auto in trip speed, the public system would consist of cars running on a separate guideway.  To avoid the need to stop at intermediate stations the stations would be place on sidings or bypasses so that each trip on a line could be nonstop from origin to destination.  To produce minimum physical impact on the environment and to minimize cost, the fixed guideway should be as small as possible.  Typically, the car would hold from four to eight people.  This has the happy consequence that the vehicle becomes more personalized, more like an automobile.  For this reason, this form of transit is called Personalized Rapid Transit (PRT).[1]  To obtain needed capacities at high levels of safety and reliability, the cars would run at close headways under redundant automatic control.  To minimize pollution, the motors would be electric and in fact need ratings of only about 25 hp.  Electric power would be required, which, of course, pollutes; but the pollution can be much more carefully controlled in a large plant that can be located away from major population centers.


            The public transportation system would consist primarily of a network of PRT lines connecting major activity centers and spaced from about one to three miles apart in accordance with the population density.  Since frequent station spacing does not affect the trip speed, stations could be placed about a quarter of a mile apart with closer spacing in the major activity centers.  Many locations near stations would exist for people to live who would desire direct access to the system.  For those who live too far from a station to walk, the existence of the PRT network makes the electric automobile entirely practical.  In this case the range required of such a car is well within the capability of a modest number of conventional batteries.  For work trips, subscription bus service could carry people to the PRT stations; for miscellaneous travel, dial-a-bus systems and public electric automobile system could be established.  The whole system would consist of PRT lines plus these auxiliary electrically driven vehicles.  Stations would be designed to maximize the convenience of the mode transfer.  The capacity of the PRT lines would be equivalent to that of about four freeway lanes in each direction but would consume about one tenth the space of a freeway and with some systems much less.  The per-mile cost of these lines would be well below the minimum cost of urban freeways.  Existence of such system in urban areas could bring about an optimum balance between public and private transportation.  People would be free to use their own cars but would have a viable alternative available to them.


            PRT is neither a pipe dream nor a paper concept.  At least five such systems are in such an advanced state of development that demonstration lines could be built and operating within two years. These systems are called Dashaveyor, Hovair, Monocab, Starrcar, and Uniflo.  A number of firms have system in earlier states of development.  At the present time, Starrcar has been selected for a demonstration at the University of West Virginia, Monocab and Dashaveyor are competing for a demonstration at the Dallas-Fort Worth Airport and it was recently announced that Monocab will be installed by private developers in Las Vegas.  Hovair is currently being considered for a demonstration in Denver.  Uniflo is being considered for a demonstration at the University of Minnesota.


            With all this activity, one is entitled to ask, “What’s the problem?”  The problem is that these developments are still limping along primarily on private funds.  While the Department of Transportation has awarded some modest contracts, the infusion of funds into effective new system is far short of the need.  The transportation situation is extremely urgent, but there is nothing close to a national commitment to develop systems like PRT.  PRT could be the backbone of an effective solution to the problem of urban transportation.  It is the hope for revitalized urban living spaces.  As such, it does threaten the vast established auto industry.  Opposition to development of PRT manifests itself in many subtle forms.  Without strong political backing, it could fade away from a lack of investment capital. 


            Proper development of PRT requires a much stronger commitment within the Department of Transportation than exists today.  To develop such a commitment may require influential political leaders from the nation’s metropolitan areas to pound on desks in Washington and demand action.  But to develop the knowledge and to bring this knowledge to the attention of our leaders requires continued programs to develop PRT.  We can only hope that the modest efforts now underway can be the catalyst to an effective national commitment.


            While developments on the physical hardware of PRT and auxiliary systems continue, broader implications of the introduction of this technology need to be considered.  Although PRT is designed to counter the harmful side effects of present transportation systems, one should not push for rapid development without considering the broad economic and social implications.  As mentioned previously, if an effective PRT system is built, it will reduce the number of jobs available in the auto manufacturing and servicing industry.   Since PRT is a much more efficient form of transportation than the auto, it is improbable that it would directly produce as many jobs as it would displace.  For this and other reasons, PRT and auxiliary systems should be introduced gradually within a framework of comprehensive urban planning so that practical experience with their impacts can be absorbed before going too far.  At the same time it may take strong pressure to introduce PRT fast enough to reverse the trend of decay of our central cities.


            On the national level, the development of PRT and its auxiliaries should be given the status of a national goal.  The major developmental systems should be demonstrated as soon as possible in realistic urban settings.  Through symposia, reports, etc., data from these demonstrations should be analyzed and made available to urban areas.  To do these things will require that the Congress form a NASA-type organization for ground transportation – a need that is long overdue.  The precedent for this action has been established through the Urban Mass Transportation Act of 1964.  In this act Congress requested a project “to study and prepare a program of research, development, and demonstration of new systems of urban transportation that will carry people and goods within metropolitan areas speedily, safely, without polluting the air, and in a manner that will contribute to sound city planning.  The program shall (1) concern itself with all aspects of new systems of urban transportation for metropolitan areas of various sizes, including technological, financial, economic, governmental and social aspects; (2) take into account the most advanced available technologies and materials; and (3) provide national leadership to efforts of states, localities, private industry, universities, and foundations.”  


            On the state and metropolitan-area level, the problem is too urgent to wait for development of a national commitment.  Since it is the metropolitan areas that will suffer from inaction, governments within these areas needed to get to work to generate a national commitment, to prepare to use information generated from demonstration programs, and to learn how to achieve an optimum balance between transportation modes.  A NASA-type ground transportation administration at the Federal level is needed, but it is not enough.  Because the results are intended to be infused intimately into the urban areas, many people within those areas will have to be trained to plan for, install and operate the new systems.  Because of strong career commitments, lack of knowledge, preoccupation with immediate problems, etc., it is not at all clear that established metropolitan organizations will be effective in planning for and studying the impacts of radically new systems, even if they are to be introduced gradually.


            Before trying to set up new organizations, the metropolitan governments should consider the possibility that the universities located within them may be the natural spawning ground for new transportation systems.  Only within the universities is it possible to find an abundance of first-class talent accustomed to working on new things and the variety of talents needed to consider all of the technical, economic, social, political, and environmental impacts of something as comprehensive as urban transportation.  The university is, of course, primarily a training ground, a fact that renders it the more suited to participation in this task.


            The Aerospace industry should also be of great help.  Aerospace engineers are accustomed to working on broad new system problems, as a result of which they have not become ossified from fascination over particular solutions to problems.  In choosing groups of systems engineers to do new things, the most important factor to consider is the psychological attitude of the group toward the problem.  If they really want to make it work, they will find a way; if they don’t, they will be very clever only in inventing reasons to the contrary.  At one time makers of wooden sailing ships were the greatest experts in transportation technology.  Would you have gone to them with an idea for iron steam-driven ships?  I think not.


            In summary, the state of urban transportation is critical.  Conventional alternatives cannot rescue cities from strangulation due to smog and congestion. Only by shifting to new forms of urban transit can our cities maintain their viability. The backbone of these new forms is Personalized Rapid Transit, a system under extensive private development in the United States.  Because of strong legitimate interests in the present transportation systems, strong and visionary political leadership will be needed to effect the necessary change.


[1] For a more complete description see J. E. Anderson “Personalized Public Transportation for the Twin Cities,” Mechanical Engineering Department, University of Minnesota, March 1970.


Last modified: January 06, 2008