Personal Rapid Transit and Urban Development

by J. Edward Anderson

The pattern of development and redevelopment that may be induced by a particular form of public transit is of prime importance to urban planners and concerned citizens. The streetcar produced strip development along its tracks. Since World War II, the automobile system has taken over as the major factor in the growth pattern of cities. The result has been what has become known as "urban sprawl" and is considered by many to be undesirable. Before examining the effect new transit systems may have on urban development and redevelopment, it is necessary to examine what it is that is undesirable about urban sprawl and what if anything can be done about it. My observations on this question come from discussions with planners and geographers, from literature, and from several decades of observation as an urban resident, which has included many years of living in both high-rise apartment buildings in the city and in the first-tier suburbs.

Urban sprawl in the United States has resulted from the compounding of individual decisions as to where to live and from the lack of enforceable land-use plans. The automobile has been a prerequisite to urban sprawl but, by itself, could not have produced it. In my experience, the fundamental driving force has been simply the desire for privacy, fresh air, closeness to nature, and a nice place for one's children to run and play. In the early days of the auto, only the wealthy could afford both a home in a nicely wooded area on the outskirts of town and a car for transportation to the office. The wealthy have influenced town politics and so were able to get better and better roads to their isolated communities. As these communities grew, they built schools and of course they made certain that these schools were of high quality.

Two more driving forces then came into play. First, the desire of parents who could not quite afford it to take advantage of the better education they felt their children could get by attending suburban schools; and second, the fact that taxes were lower outside the city limits. After World War II, GI home loans with low down payments and low interest and similar auto loans were the final factors needed for development of a market for single-family suburban homes for people of average income. Land developers were ready to supply the market and, from the viewpoint of most of them, profits would be maximized if every possible lot were developed. Community objectives like parks and playgrounds appear to not have been of prime concern to private developers. Also, these facilities do not contribute directly to the tax base. From the viewpoint of the individual family, the move to the suburbs was a thrilling event. It would have been difficult indeed to persuade people that there could have been anything wrong with it.

Urban sprawl does, however, produce detrimental effects. Some of them are the following:

1. The cost per dwelling of utilities is higher in the lower-density suburban communities. When people first moved to the suburbs the pattern was to have one's own cesspool and well. Power lines were provided to meet the demand. As lots filled up, cesspools became overloaded and wells contaminated. Pressures built for sewers and water lines as well as for better roads, schools and playgrounds thus causing property taxes to go up, reflecting the real costs of low-density living. As a minimum, it would seem desirable for metropolitan authorities to fully inform families of the obligations they will incur in moving to a new suburb. A problem now is that the family is simply not aware of the total financial burden it is assuming when making the down payment. To so inform people would of course run counter to past policies of encouraging maximum growth.

2. Low-density housing tends to isolate families and to decrease the sense of community. In families that have been able to afford only one car, the wife is much more isolated than when she lived in town and could walk to many places of interest. Margaret Mead has written and lectured in depth on this topic. Quite evidently an important additional factor in this isolation is the frequency with which Americans move.

3. The cost per ride of providing public transit is inversely proportional to population density. Thus, bus systems that were economically viable in the inner city could not survive in the suburbs. Lack of public transportation increases the isolation of those with no access to an automobile.

4. Conservationists have warned that too much valuable farm land is going into housing and have calculated that if this land continues to be gobbled up for a few more decades at the present rate, the United States will have to worry about an insufficient supply of good farm land. For example, many formerly fertile agricultural valleys in California are now smog-filled suburbs.

5. The lack of regional planning in the United States has resulted in far too few good parks in the suburban areas. As a counter example, in Minneapolis, foresighted community leaders over eighty years ago caused the city to purchase lands around a chain of lakes on the periphery of the city. Many scoffed at such a ridiculous waste of public funds, but these lands now form a chain of parks that are a prime asset to the whole community. They not only have recreational value, but have been an obvious factor in keeping many of the more affluent within the inner city. The parks have been a magnet to attract desired development. It is a real loss to the whole metropolitan area that more recent community leaders did not follow the example of there forefathers. As a result, there are far too few parks in the suburban areas of the Twin Cities. I have been persuaded that the current form of urban development is detrimental and that policies should be developed to shape growth in desirable ways. The basis for these policies should be a very thorough quantitative understanding of the underlying factors that have determined current growth patterns, and that may determine growth patterns in the decades ahead. It is important to appreciate that for many reasons the future will not be a mere extrapolation of the growth trends of the past. I am also very aware of the quantitative arguments of people like Peter Gordon and Harry W. Richardson in their online paper entitled "Are Compact Cities a Desirable Planning Goal?" [1].

People behave in their own best interest as they see their interest, not as some planning group may see it. Some of the policies I believed, at least when I first wrote this report, should be developed (and in some areas are being developed) are the following:

Identify and purchase appropriate lands for parks and playgrounds.

Develop information for potential suburban homeowners in order to inform them of the full potential cost of moving to the suburbs.

Review and approve, by a central and democratically elected authority, all requests to build roads, transit lines, sewers, water lines, and power lines; and identify areas in which such approval will not be granted.

Concentrate non-residential activities in well-located major centers of predetermined maximum daytime population. The maximum population of each should be determined from consideration of the ability to supply all utilities including transportation. These maxima should apply to the downtown as well as to other major centers. The philosophy of the greatest possible growth of any one center should be abandoned as being socially undesirable to the community at large.

Establish through research the desirable range of population densities. We have pointed out difficulties with too low a population density. Too high a population density is also socially undesirable.

Create a transportation plan with sufficient capacity to provide the needs of the above policies. Since the flow in any transportation corridor is proportional to the average trip length, a pricing system should be worked out to discourage longer trips.

Within a framework of policies such as those suggested above, it is meaningful to discuss the possible effect of a particular mode of transportation on urban development. A public transit system may have a significant influence on urban development if it can attract a significant fraction of the total number of trips within the urban area, not just to the downtowns; and if it can help reverse the major driving forces that cause people to want to move out.

In our auto-oriented cities, no conventional transit system is able to fulfill these criteria in a significant way. Bus lines can be changed too easily to influence development decisions. Also, the service concept of conventional bus lines fails to address the needs of people and therefore fails to attract a significant fraction of the trips. People are asked to bend their habits to meet the needs of the system, i. e., waiting for vehicles, picking up and letting off other people unconnected with one's own trip, and transferring. New service concepts like door-to-door subscription service or dial-a-ride may increase transit ridership--a desirable goal--but they are too much like the auto to produce changes in development patterns. Studies of the influence on development of potential new on-line-station, fixed-guideway transit, i. e., rapid rail or so-called "light rail" transit, come to similar conclusions because the cost per ride is too high in low and medium density communities to build a sufficiently extensive system. The cost per ride is too high both because of high construction cost and because the service concept is too inferior to the auto to attract many trips. These systems may cause some concentrated development near downtown stations, but will do practically nothing about urban sprawl.

Now consider Personal Rapid Transit . If PRT does influence urban development and redevelopment in significant ways it will first have to be a very successful system in terms that will be reflected in the cost per ride. For many reasons, we believe the cost per ride will be close to if not below a reasonable fare, particularly if the system is used for movement of both people and goods. In the following discussion, it is assumed that this is true and that properly designed overhead guideways will be acceptable at least along major arterial streets, freeways, and rail tracks; since only then can PRT affect development decisions. Only by going to a different level will it be possible the affect congestion. In the downtowns, these guideways may be as close together as two blocks, but in residential areas the lines more likely would be placed along arterials one half to one mile apart. A major point is that the location of the lines should be determined in accordance with an overall development policy and only with concurrence of the affected residents.

If PRT becomes accepted, there will be pressure to extend the lines farther and farther into the suburbs. But, if this is done according to a carefully developed plan, then it need not produce the undesirable features of urban sprawl. Because the system would be designed to be physically attractive and quiet, residential communities could be planned and built near the lines to minimize the walk to the stations. The spaces farthest from the lines could be planned as open spaces for a variety of purposes. Small electric cars and bicycles could provide access for those too far from the lines to walk. With a network of high-capacity PRT lines in the inner city, the use of automobiles would reduce. This would reduce the negative side effects of the auto, i. e., noise, air pollution, physical blight, accidents, excessive land use, etc. Many parking lots could be restored to green areas. Streets could be narrowed and partly converted into linear parks thus further reducing auto traffic and increasing the beauty of the city. The result would be a city that would begin to attract and hold people rather than drive them away.

Downtowns could restrict the use of automobiles without causing economic stagnation because people would have a viable alternative mode of travel, indeed an alternative far more convenient as a means of access to downtown than exists today. With easy access to the downtowns and other major centers, people would go to them because of the attractions they offer. It would thus seem that PRT would satisfy the needs of downtown interests as well as the interests of the community at large. Coupled with other policies, PRT appears capable of producing significant positive influences on the whole community.

I am reminded of a statement by Daniel H. Burnham in the preface of a report of a comprehensive city plan developed for Chicago in the early years of the 20th Century : "Make no little plans; they have no magic to stir men's blood and probably of themselves will not be realized. Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will never die, but long after we are gone will be a living thing, asserting itself with ever-growing insistence. Remember that our sons and grandsons are going to do things that will stagger us. Let your watchword be order and your beacon beauty."

This paper is based on the Appendix to a statement on National Transportation Policy the author gave to the Subcommittee on Department of Transportation and Related Agencies Appropriations, U. S. House of Representatives, March 6, 1974.




Last modified: October 17, 1998