The Dualmode Transportation Revolution

by Francis D. Reynolds

The great volume of Transit Alternatives e-mail lately has been interesting but also disturbing. My intent here is to indirectly take issue with some TA contributors and to add further thoughts of my own.

I am a retired Boeing (including Morgantown-project) engineering manager, inventor, consultant, and hands-on hardware-oriented guy. Some years back I conceptually designed the "HiLoMag" dualmode system. My thinking then was broad, and it still is. Conceiving of and designing the hardware is the fun part, for me at least, but to do the job right we must balance many major factors. These include traffic congestion, transit for non-car owners and non-drivers, fossil-fuel depletion, atmospheric pollution, global warming, availability of materials, the economics, the total potential market, politics, opposition from labor and existing industries and organizations, esthetics, the foibles of human nature, and you name it. I am knowledgeable in a few of these areas, but quite ignorant in others, therefore I, for one, am incapable of optimally integrating all of these diverse forces. This enormous project is going to employ thousands of people in many walks of life.

The arguments in the TA mails often include several of the above concerns, but few people address the total picture in their proposals. There is no question that our current short-range transportation problems are urgent and must to be faced, and I understand the needs and problems of TA members who have startup companies and are trying to find niches where they might make a profit. I feel for them, but I have chosen to let others worry about tomorrow, and to direct my attentions to some decades after tomorrow, to the slightly later future. In doing that I need to take issue with some of the immediate-future people where I think certain of their actions will be unproductive, unwise, and perhaps damaging to the progress of our coming transportation revolution. The more things we do that bomb, the more difficult it will be to get support for the right things we try to do. I do not believe that the addition of single-mode PRT-only guideway systems to our present transportation mix will be a wise choice since dualmode with PRT would be many times better on a large number of counts.

Kirston Henderson with his Megarail Company, Palle Jensen with the RUF system, and several others are proposing and working toward combined PRT and Dualmode sysems. An excellent goal. More power to them, but to my eye many of them don’t seem to be thinking broadly enough. Most of the PRT-only people seem to be proposing lightweight guideways with very low vehicle-weight limits. Don’t get me wrong; unnecessary weight in any transportation system is bad for several important reasons. But weight restrictions that greatly limit the utility of the system are false economy. I propose a national dualmode guideway system with vehicle weight limits that would permit dualmode buses carrying maybe two dozen people, and dualmode light trucks able to carry a couple of tons of perishable or high-priority freight. Heavier loads than those can stay on the streets and highways, and on the freight railroads. I also recognize the importance of keeping aerodynamic drag low, and the related importance of platooning, especially for vehicles on the high-speed intercity guideways. The dualmode vehicles will be different from our present cars, buses, and trucks in a great number of ways.

Fellow critics of the status quo, I urge you to think bigger. Our highway system is now a one-size-fits-all infrastructure. Little systems such as many of you are proposing would get a few automobiles off of the highways, but "a few" is far too few. The "patients" (human transportation, energy reserves, and the environment are all sick, sick, sick, and major surgery is required. Isolated attempts to cure one small part of these many ills could at best do just that, do one small part of the total job of restoring the overall health of these systems.

Fixing one problem at a time with unrelated fixes is what we may do with an old and decrepit automobile; but when its condition degrades to a certain level we get a new and improved car instead. That is the way I see our present highway system: old, obsolete, and often functioning poorly. It is past time for a major upgrade. To our great fortune a type of major upgrade has presented itself that will cure or greatly alleviate not just a few but most of these worldwide problems. This step will be the addition of a Universal Standardized Multipurpose Dualmode-guideway Transportation System. This revolutionary upgrade will be made completely compatible with and will generally run parallel with our existing streets and highways, carrying most of the same types of traffic that they already carry. And it will provide such speed and capacity that in many places we will have an excess of conventional highway lanes, not a constant shortage.

We can’t exclude the possibility that there is an even better solution than dualmode for solving all of our multi-headed transportation and related environmental problems, but no one has been able to come up with it. On the other hand, around fifty creative individuals worldwide have independently concluded that dualmode transportation is the right solution. When a number of people come up with basically the same invention the chances are excellent that it will indeed turn out to be the right solution. History shows similar simultaneous multi-inventor phenomena during the origins of most of the major inventions of humanity.

Many have said or implied that automobiles are bad and must be eliminated. If by "automobile" they mean our present fuel guzzlers, I agree with them. But the fact of petroleum depletion assures us that most automobiles will soon be off the roads anyway. However there is nothing wrong with the concept of private-vehicle ownership per se; the problem is that with continuing population growth, and the advent of fuel-depletion and global-warming, our present automobiles, streets, and highways can no longer fill the bill, especially for the future. So we need to design and build a transportation system that will fill it--all of it. But planners who propose to exclude privately owned vehicles from future transportation will never succeed. The average person in most developed countries of the world loves cars, for a number of reasons; and in free societies the customer ultimately rules. However, car lovers will learn that their future cars must differ from existing automobiles. Increased usefulness will be one of many ways in which these cars will differ.

In my mind there will ultimately be no contest between dualmode and PRT, at least in areas of the world where the automobile reigns supreme. No contest, because the dualmode guideways will carry PRT, just as they will provide almost all of the services that are now provided by our streets-and-highways system.

Earlier versions of the following chart has been used in some past articles and presentations, but it is repeated here because it is obvious from TA and other discussions that many people are unaware of some of these facts, they don’t believe them (yet don’t necessarily debate them), have forgotten them, or choose to ignore them. "Don’t bother me with facts, my mind is made up" is an oldie but a goodie. I recognize that this chart will put many PRT advocates on the defensive, and cause them to immediately start formulating their rebuttals, but I urge them to first think about what is being written here, and why.


Factor PRT Dualmode
Technologies Needed Available Available
Power Electric Electric in both modes
System Cost High Lower (far fewer guideways    needed
Will it carry PRT cars? Yes Yes
Can carry private cars? No Yes
Can carry transit buses? No Yes
Can carry freight? Small items Larger items
Can carry light truck? No Yes
Resultant market size? Low Enormous
Financial subsudies? Needed Not needed
Door-to-door service provided? No Yes
Resultant popularity and use? Low Very high
Overall safety? Some improvement Great improvement
Rights-of-way required A great many Many fewer
Environmental impact Slightly favorable Very favorable
Would reduce air travel? No Yes
Reduced energy requirements? Slightly favorable Very favorable

Note: Not all proposed dualmode systems would satisfy the above. A maglev LSM dualmode system is assumed. For general details and explanations refer to:
and for technical details, to:

We must provide adequate transportation for those who do not own cars or who do not drive because of personal choice, age (in either direction), disabilities, or economic reasons. Better, faster, cheaper and safer transportation than these car-less people now have will be provided by the dualmode system. And it will be better than could be provided by affordable PRT or any other single-mode transit system whether such system uses existing rails, existing streets and highways, or new single-mode guideways. Our dualmode system will include all of the PRT and other forms of transit for which there is a market. The size and nature of that market will vary in different cities and in different countries, and the mix will change as the market changes.

PRT on a dualmode guideway system could be made essentially the same as that proposed for PRT-only systems, but that would make little sense. The logical form is dualmode PRT, where the cars can leave the guideways and be driven to final destinations, just as the owners of dualmode cars will do. Such a service will be seen to be like rental cars, with the added great advantage of being dualmode.

Some people have wondered how a dualmode system and a PRT system could be effectively integrated. My prediction is that the dualmode PRT service won’t be integrated with the guideways any more than any other type of dualmode vehicles will be integrated with the guideways. Dualmode PRT cars will be very comparable to rental cars and we will treat them just like we do our present rental cars. The streets and highways accept private and rental cars equally, and so will the guideways. PRT car agencies will doubtless include present rental-car agencies. The customers will take the dualmode PRT cars any place they want to, including onto the guideways.

It has been recognized that the number of guideways and number of stations required become very high for a single-mode PRT-only guideway system if the walking distance to the nearest station is kept reasonably short. But with dualmode no walking is necessary, so the guideways and stations can be many times farther apart. A barely adequate single-mode PRT system would require around eight times as many miles of guideway and sixty-four times as many stations as a completely adequate dualmode system including PRT. These startling factors will make even a light PRT-only system cost many times what a dualmode system will, and make the PRT far harder to sell when the public understands the differences.

Note that when we elect to carry dualmode PRT instead of single-mode on our system, no additional guideways or stations need be added to the guideway grid. Since no special requirements will be imposed upon the guideways for the acceptance of dualmode PRT cars; the much lower cost of the dualmode system will not be compromised. Dualmode PRT-car pickup and drop-off points will be provided by the rental agencies. They will not be part of the guideway system, they will cost far less than guideway stations, they can be as abundant as the market demands, and they can be located at places removed from the guideways.

One form of transportation for people who do not drive will be the dualmode taxi. On long trips a taxi driver could pick up a "fare," deliver him or her to the nearest guideway, and then exit the car. The customers would now have complete privacy until they pick up another driver upon exiting the guideway system. This service may be compared with the dualmode PRT business with the addition of a hired driver to deliver a car and then drive the fare to the nearest ramps of the guideway. Dualmode taxi service will cost less than present taxis since full-time drivers won’t be required.

For less personal and cheaper service for non-drivers or non-car owners there will be transit buses. The cross-country Greyhound-type of service may end up on the guideways only; but the city mass-transit buses will be dualmode, using both the streets and the guideways. The guideway ride will be fast, and the street-mode part of the trip will also be faster than now, because the street traffic will be greatly reduced. A major part of the street-traffic reduction will be accomplished by automatic parking directly from the guideways.

The guideway organization should provide only the guideway services. It should not provide the cars, buses, and trucks to be used any more than the streets and highway systems people provide the vehicles used on those systems. But of course enforced interface requirements between the vehicles and the guideways will be necessary, just as they are between present vehicles and the streets and highways.

Many PRT advocates propose narrow lightweight guideways, "to make the system affordable." Let us examine that. Our railways started out small and light. Our streets and highways system started small, and could originally carry only light vehicles at low speeds. Our airlines started out with light small slow planes and short light-duty airport runways with no traffic control. All three of these basic transportation systems expanded in size, weight, and complexity as the population grew and the demands for faster, heavier, and expanded services developed.

The present situation is quite different however, because now an enormous and broad market already exists, and those huge needs are no longer being adequately served. Therefore it makes sense to plan a large relatively heavy-duty system initially; one that will be able to fill this enormous demand, not only for people-travel but also for light freight. To do less would prolong the pain and the environmental damage. For example: assume that 2% of the people now travel by existing transit systems. And assume that we put in a single-mode PRT system and are able to double the number of people traveling by transit. Wonderful! But note that the people in automobiles on the streets would have dropped from 98% to 96% of the total; an almost negligible change. If instead we put in a dualmode system and 80% of the people use it, we have only 20% of the travelers left on the streets. And the wide-grid dualmode system cost will be far less than that for an ineffective tight-grid PRT-only system. We need to include in the "cost," the social, energy, and environmental costs, not just the monetary cost of building the guideways.

An oversimplified example? Certainly, but you get the point. Don’t try to solve vast problems with half-vast ideas. Don’t be penny wise and pound-foolish. Do it right the first time so we don’t have to do it over.

Those who say it can’t be done should not stand in the way of those who will be doing it.

What about air travel? We speak of alternate energy sources for automobiles. And we point out that electric guideways will give us the option of converting any other form of energy into electricity. But airplanes don’t fly well dragging long extension cords, and the low energy-density of batteries, hydrogen fuel cells, and solar cells would be far from adequate for practical airliners. A great reduction in air travel is inevitable as petroleum becomes less and less available. What is going to replace flying? Isolated PRT guideway systems certainly couldn’t. But a standardized national network of dualmode guideways, running at say 200 miles per hour nonstop between cities, will nicely replace most domestic air travel. For trips up to around a thousand miles the guideways will provide shorter overall travel times in addition to reducing frustration and reducing costs. The sum of the times to get to and from the airports and to go through all of the security and other processing required is frequently more than the flying time. Looking still further ahead, evacuated-tube travel times will be less than those for long flights as well as for short flights. Boeing will likely be back in the ground transportation business.

In summary, I envision an overwhelming need for a standardized national and international dualmode guideway system (comparable to our highway system) as soon as we can get it. Because of the high velocity at which it could operate, and the very close spacing of the vehicles that is possible (I estimate around one-foot clearance), this system could have capacity enough to carry all of our existing traffic in most places with a single lane in each direction. Planning what to do with some extra highway lanes will be a pleasant switch from trying to plan how to get more lanes built. We needed a universal multipurpose dualmode system decades ago, and it would take at least a decade to design and build one even if we had a national go-ahead now, and if no organizations opposed it. The time it will take in this real world is at least twenty years, and maybe fifty. The later we start the more horrendous the fuel shortage, global conflict, global-warming, and traffic crises will become. It is already too late to alleviate these problems for ourselves or our children, but we will help our grandchildren if we can get the right people to face up to these truths and start taking some appropriate actions. It has been said that doing the impossible takes a little longer. The really scary thing is that we don’t have a little longer. As we know, these major crises are already here and are rapidly getting worse. Have a nice day.

home2.gif (1492 bytes)

Last modified: May 02, 2004