Why, After Decades, Has Personal Rapid Transit Not Yet Been Widely Accepted?

by J. Edward Anderson, Ph.D., P. E.

April 19, 1997

I am frequently asked: If PRT is such a good idea and one that has been around for decades, why hasn't it been widely accepted? There was considerable interest in PRT in the late 1960s and early 1970s, so much that the idea caused several proposed heavy rail projects to be stopped. Capital grants had become available for conventional rail systems and the promoters of such systems, who had the dominant lobbying power in transit circles, found that PRT adversely affected their plans. They therefore persuaded Congress to eliminate the competition of a compelling new idea. But, the need for PRT could not be eliminated, and it is now in a state of reemergence.

Early Interest in PRT

In 1964 Congress created UMTA (the Urban Mass Transportation Administration), not only to revive dying municipal bus companies, but to fund the deployment of BART-type rapid rail systems in cities all over the United States. Evidently the lobbyists for the status quo did not perceive that the new organization would get involved with new systems, and they failed to stop placement of a paragraph in the UMTA Act that directed that new systems be studied. Of 17 studies authorized, one can still be found in libraries in summary form [1]. Its key conclusions are the following:

"In general, the results of our analysis made clear that, even with the most optimistic view of what might be achieved through improvement of the existing methods of transportation, such improvement cannot satisfy the real needs of our cities in terms of service."

"Computer models of cities suggest that in certain circumstances installing novel `personal transit' systems may already be more economic than building conventional systems such as subways."

On January 21, 1972 the New York Times [2] announced that the Nixon Administration was embarking on a program "for using technology to improve our everyday lives." The first project named was the development of a high-capacity PRT system.

This announcement followed:

a) Completion in 1968 of the above-mentioned studies on new personal transit systems funded by UMTA at $500,000 each, which showed strongly positive benefits from the deployment of PRT systems;

b) Start of federally-funded work on the Morgantown so-called PRT system;

c) Reports of extensive work on PRT in many places around the world, as reported in November 1971 at the National Conference on Personal Rapid Transit; and

d) Detailed study of PRT by a group of NASA engineers working in the Executive Office of the President, including study of the excellent work which the Aerospace Corporation had been doing on a small-guideway, high-capacity PRT system, which had minimal visual impact and modest costs.

(The Aerospace Corporation had perhaps the finest group of system engineers in the world. Their PRT work was outstanding and was so recognized by the White House, whose initiative was directed at further development of the Aerospace PRT system .)

In March 1973 UMTA Administrator Frank Herringer testified to the House Appropriations Committee [3] that "...a high-capacity PRT could carry as many passengers as a rapid rail system for about one quarter the capital cost."

The record of those hearings contains a quantitative comparison of PRT and conventional rail systems that supports this statement. Herringer went on to say: "A DOT program leading to the development of a short, one-half to one-second headway, high-capacity PRT system will be initiated in fiscal year 1974."

The Aerospace Corporation would have led this development program.

In September 1973, after experiencing long waits at gasoline stations and being informed in the Denver Post and the Rocky Mountain News in great detail about automated, small-vehicle, nonstop, origin-to-destination service possible with the true PRT concept, Denver citizens voted a one-half percent sales tax with the understanding that the result would be the development of a PRT system for Denver.

Between 1970 and 1973, a group at the University of Minnesota, funded by the Minnesota State Legislature, had been studying all of the PRT programs then underway throughout the world. In December 1973 that group recommended that the Aerospace Corporation work was the most promising and that a prototype of their system should be tested at the Minnesota State Fairgrounds. In April 1974, after extensive hearings and site visits, the Legislature passed an Act [4] that directed the Metropolitan Transit Commission (MTC) to develop plans for a system that met the definition of PRT.

Conventional Rail Fights Back

The conventional rail community had expected that, under the UMTA Act, the federal government would be handing out large sums of money to subsidize construction of conventional rail transit systems in cities all across the country. To their dismay, the promise of PRT generally, and the Aerospace system in particular, had stopped several heavy rail proposals. Instead of recognizing the long-term advantages to their industry of supporting the PRT initiatives, they felt that it was more in their interest to rid the world of the competition of a new idea. In August 1974, as a result of heavy lobbying by the suppliers and planners of conventional rail transit technology, the UMTA High-Capacity PRT Program was turned into a harmless, poorly-funded research program that ultimately died in the 1980's. Moreover, the design of the Morgantown system had been micro-managed by UMTA engineers who did not understand the concept of PRT. The result was a system of 20-passenger vehicles running on an over-large guideway. It could never became a commercially-marketable system and its high cost put a worldwide damper on the budding PRT industry.

For its part, the Metropolitan Transit Commission (MTC) had strongly recommended that an elevated, heavy rail system be built in the Twin Cities; nonetheless, pursuant to their instructions from the Legislature they called for bids on development of a plan for a PRT system. They received two bids: one from the Aerospace Corporation that reflected their thorough work in PRT planning and design , and one from DeLeuw Cather, a transportation consulting firm that, in addition to designing the BART system in San Francisco, had vigorously opposed PRT in favor of conventional rail. The MTC picked DeLeuw Cather who proceeded to develop a plan for a "PRT" system that used twenty-passenger vehicles traveling on ten-foot-wide guideways. The economics of that design were unfavorable, and, as a result, the Minnesota initiative died.

Meanwhile, the Denver plan was converted into a system of large, manually driven vehicles running on rails in the street and obtaining power from an overhead wire. Such systems had been renamed "light rail" (LRT). (Note: the Denver plan is discussed in a book by Burke )

Since the demise of UMTA's early efforts, transportation consultants have advised city planners to look only at "proven" systems. Because of today 's growing highway congestion, the public has cried out that "we must do something;" and the consultants, many of whom had lobbied against PRT, say repeatedly that that "something" is either conventional heavy rail or, because heavy rail is so dreadfully expensive to build, LRT, a modern version of the streetcar. What the consultants are really saying, of course, is that they know how to design and build those systems, never mind that they do not get enough people out of their automobiles to justify either their huge capital costs or their continuing and substantial operating deficits.

PRT Reemerges

Now that federal subsidies are beginning to dry up and people must put up their own money to cover the capital and operating costs of conventional transit technology, the picture is finally beginning to change, notwithstanding the lobbying efforts of the suppliers of conventional transit technology and their consulting friends. People around the world are once again looking seriously at PRT.

In the late 1980s, the leadership of the Northeastern Illinois Regional Transportation Authority realized that they could not solve the transportation problems in the Chicago Area with only conventional, or "proven," rail systems and more highways, and that a new solution was badly needed. They became acquainted with PRT and, after investigating widely, in April 1990 announced a program to develop a high-capacity PRT system. After a bidding and preliminary-design process, the Raytheon Company , using designs developed at the University of Minnesota, was chosen to team with the RTA to develop a prototype PRT system. Their work has now reached the test-track stage, and the expectation is that they will have technology ready for deployment in 1998.
(Update: The test program was completed successfully, but shortly thereafter the Raytheon Company terminated the PRT 2000 program due to a sharp cutback in the value of its stock and other difficulties). It is now (2003) being carried forward by two companies, one in Korea (www.prtkorea.com) and the other in the U.K. (www.yorkprt.com).

Stimulated by the Chicago initiative, planning and design studies for high-capacity PRT systems have received governmental support in England and Sweden , and private support in Korea . These studies posit small-car, small-guideway designs similar to that developed at the University of Minnesota. Together with new studies underway in the U.S. and in other countries, they bear out the rationale underlying the Chicago project . Thus, it looks as though the proponents of the status quo in transit technology may finally lose their battle with the future. Conclusions reached in the new studies are most inspiring:

"PRT, after about four decades of study and some development, including over a decade of relative neglect, should be moved back onto the public agenda for consideration as one of the promising options for improving urban transit"[5]

"Our recommendation is therefore clear. A PRT system provides such a broad range of desired qualities that it should be given the highest priority in research, development, testing and demonstration for implementation in the urban environment. Göram Tegnér, TRANSEK, Sweden. [6]

"Advanced PRT systems provide a cost-effective and environmentally advantageous solution to the problems of transport in the 21st century." Martin Lowson , Bristol University, England. [6]

"PRT technology offers the way to achieve our objectives while at the same time offering enhanced urban form and improved lifestyle." Woobo Enterprise , Inc., Seoul, Korea. [6]

"But even if the fuel consumption of cars is reduced by 50% in the 21st century, they cannot compete with PRT." [7]

"Nationally, for well over two decades, PRT's efficiencies have been ignored while hyper-costly and under-serving `light rail' trolleys have been standing in as the highway's one rapid transit alternative, subways being non-competitive." [8]


1. William F. Hamilton and Dana K. Nance, "Systems Analysis of Urban Transportation," Scientific American, 221:19-27(1969).

2. New York Times, January 21, 1972, page 1.

3. Hearings before a Subcommittee of the Committee on Appropriations, U.S. House of Representatives, Ninety-third Congress, First Session, 1973, page 876.

4. An Act relating to metropolitan public transit; directing the metropolitan transit commission to plan an automated small-vehicle fixed-guideway system; authorizing tax levies upon property within the metropolitan transit taxing district. S.F.No. 2703, Chapter No. 573, approved on April 11, 1974 by Governor Wendell R. Anderson. State of Minnesota, State Capitol Building , St. Paul, Minnesota 55155.

5. "Personal Rapid Transit (PRT) : Another Option for Urban Transit?, Journal of Advanced Transportation, 22(3):196-314(1988), a report prepared and endorsed unanimously by 13 transit professionals.

6. Results of these and other studies will be published in a special issue of the John Wiley journal Infrastructure, which is to be available in late April,1997.

7. Eva Gustavsson and Tomas Kĺberger, "Energy use in Personal Rapid Transit: Building and running Personal Rapid Transit in Sweden," Journal of Advanced Transportation, 30(3):5-15(1996).

8. Andrew Euston, FAIA, "Community Sustainability: Urbanization & Infrastructure, Enterprise & Design," Office of Community Planning and Development, U. S. Department of Housing and Urban Development, 31st Annual Federal Workshop on Urban Environmental Design, Washington, D. C., February,1997.

Dr. J. Edward Anderson can be contacted at 5164 Rainer Pass NE, Fridley, Minnesota. Fax: 612-586-0878; e-mail: jeanderson@aol.com He has also written a paper on the history of PRT which provides additional detail and background on the topics and issues discussed here. His
most recent work can be seen at www.skywebexpress.com (formerly know as Taxi 2000)

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Last modified: March 19, 2004