DualMode, the Transportation of the Future

by Francis D. Reynolds, PE.

Presented at the New Visions in Transportation Conference

Aspen, Colorado, October 20, 2000


In this conference you have already heard others speaking on dualmode transportation. Not knowing just what they would cover I have probably planned to go over some of the same ground they did. That is fine. It they thought something was important to say, and I think it is important, then it must be worth repeating.


In the future we will have even more private cars, yet we will avoid the problems we now have—by using our cars in two distinct modes. The cars may be standard or specialized, depending upon the details of the system. They will be driven in the normal manner on the streets, and they will travel automatically on high-speed dedicated guideways—but their drivers won't be driving. Trips of more than several miles will be on these guideways rather than on the highways. A dualmode system will be even more "personal" than "Personal Rapid Transit," since we will be using our own cars. And it will also be more "rapid," than PRT since we won't have to walk to and from stations. We will travel from door to door as we now do, without getting out of our cars, but we will travel safer, cheaper, faster, with less stress, and with neither gasoline nor pollution.

The Automated Highway Systems (AHS) concept (see Special Report #253) also proposes manually driven and automatic modes, but the term "dualmode" has come to mean a system that incorporates most of the intelligence in a separate guideway network as opposed to putting it into the cars. Most AHS thinking seems to concentrate on using our existing highways and our existing automobiles, with some additions to both the highways and to the cars.

This "use-what-we-have" goal seemed like a good idea at the time but it would be penny-wise and pound-foolish. AHS would not solve our energy problems or reduce our global warming problem, it would do relatively little to relieve traffic congestion, and the way it is designed its safety record would probably be worse than that of ordinary highways.

A dualmode system will solve not just a few but most of our transportation and transportation-related environmental problems in one fell swoop. And some of the things that dualmode transportation will do for us can't be done any other way.


Dualmode systems in general have many advantages over conventional automobiles and highways and over transit systems and trains. Dualmode will reduce highway traffic to a dribble—by getting most of the cars onto the guideways instead. A less obvious advantage is that dualmode will also reduce the jams on urban streets. This will come about because a high percentage of guideway cars going to the cities will not exit to the downtown streets at all. These cars will be parked directly from the guideways. (Automatic valet parking with no one to tip.) So not only will street traffic be reduced, so will street parking pressures.


The guideways will carry almost all of the types of vehicles now used on streets and highways. Most of the traffic will consist of private cars, but there will also be transit buses, Greyhound-type intercity buses, rental cars, taxis, school buses, delivery trucks, cross-county freight traffic, and possibly personal-rapid-transit vehicles. It is expected that a high percentage of the dualmode private cars for commuting will be small, perhaps two-passenger vehicles. Small cars tend to be more dangerous on the highways, where they have to compete with much heavier cars and trucks; but size will make no difference in safety on the constant-speed guideways.

Most of the vehicles will be dualmode—used both on the streets and on the guideways. But the cross-country buses and the long-distance freight vehicles will be single mode, operating only on the guideways—with no drivers. The freight vehicles will be more like cargo containers than like trucks.


The guideways will operate nonstop at full speed day and night, just as our highways should if they weren't jammed. I suggest a constant system speed of 60-mph in and around cities and a constant 200-mph on the guideways between cities. With synchronous propulsion the cars may travel only one foot apart.

These kinds of numbers provide enormous system capacity. At 60 mph a single guideway lane would carry the traffic of twelve highway lanes, and at 200 mph one guideway lane would be equivalent to forty highway lanes. Adding more lanes will be a thing of the past. And the one lane of guideway will cost far less than twelve or forty lanes of highway.

Domestic airline traffic will be greatly reduced by our dualmode transportation system. When we include reservations, the trips to and from the airports, parking, cancelled flights, late flights, baggage checking, security checking and all the rest, the 200-mph guideways will be faster than flying for trips up to perhaps a thousand miles. And guideway travelers will have privacy instead of someone else's crying kids. They will also have their own cars to use at their destinations instead of airport buses, rental cars, or taxis.


If you wish to enter the guideway system you will drive into an "entry stop," shut off your motor, and key the number of the desired guideway exit into a keypad on the dashboard. That exit number will tell the navigation computer where to send you, and tell the billing computer how much to charge you for that trip.

Meanwhile electronics in the entry stop will be reading a chip in your car that identifies the car and provides other vital statistics. At the same time an automatic system will check the operation of all parts that are essential to safe travel on the guideways. If a vehicle fails to pass any of these requirements it will be denied access to the guideways and must return to the streets.


After these preliminaries, which may take 30 seconds, the vehicle will be accelerated to guideway speed, and merged with the traffic on the guideway. "Switching" actions will be initiated automatically in the vehicles, not by switching the "tracks" as is done on railroads. And the cars will switch from one guideway to another at full speed, the same as we merge with and leave freeways at full speed. The dualmode guideway system will have much more in common with our highway system than it will with the railroads.


Most dualmode cars will be battery-electric or fuel cell powered for street use. But note that most of the time they will be on the guideways using guideway power. Batteries or hydrogen tanks that are now inadequate for highway use will be more than adequate for dualmode with its limited street needs. In the early years of the system internal combustion engines will probably be used in the street mode, since these early cars will need to use the highways where guideways are not yet available.


The amount of AC power required for the guideways will far exceed any excess capacity in our present power grid. The additional power needed can't be made from petroleum or natural gas, because the readily accessible deposits of both of them will be mostly gone. We have plenty of coal, however. Coal is now used to generate over half of our electricity. But it does not work at all well in internal combustion engines, and coal as a source of electricity is far from green. However, even if we burn coal to push electrons through the transmission lines, the overall dualmode system will be roughly twice as efficient as automobiles. So transportation will burn less fuel and therefore generate less CO2 than it now does. And if we use solar power, as Dr. Guadagno proposes, so much the better. The guideways will be electric powered. We can make electricity from any energy source, while internal combustion engines demand petroleum or other liquid of gaseous fuels in short supply.


The different dualmode system inventors have proposed different details. In some systems "true dualmode cars" would be equipped to run on the guideways directly, and in other systems there would be interfacing pallets between conventional cars and the guideway. There are dualmode systems where the cars would ride on top of the guideways and ones where the cars are suspended below overhead guideways. There are proposed dualmode systems where the cars would be supported by conventional rubber tires on both the guideways and on the streets, and others would have the cars ride the guideways on steel wheels and rails.


Some dualmode inventors, including myself, propose maglev guideways. Maglev trains are quite well developed, especially in Japan and Germany. They are very fast, quiet, and safe. But; trains are obsolete whether they are supported by steel wheels on rails or by maglev. For that reason maglev trains will die in their infancy. A big maglev train project in Germany was cancelled just a few months ago.

But the concept of magnetic levitation per se has wonderful advantages for dualmode systems, where the cars are not coupled into trains. Dualmode cars will be physically independent, privately or commercially owned, and will go their separate ways, just as vehicles on our highways do. Some of the advantages of maglev are obvious: If the cars are floating with their street motors off they won't be wearing out. And neither will the guideways wear, so they won't develop faulty rails or potholes.


The linear electric motors used to propel maglev vehicles are usually integrated with the levitation system. Linear motors are like ordinary AC motors except that they are laid out flat so that the working parts move linearly instead of rotating. In many cases the same magnets and coils can be used for both the levitation and the propulsion. A continuous stator is built into the guideway, and the moving parts of the motors are rigidly attached to the levitated cars. But the AC armature windings can be either in the cars or in the guideway, with the field magnets in the opposite location.


The efficiency of the electric propulsion will be ninety-some percent compared to about 30 percent for internal combustion engines. Magnetic support alone doesn't require any energy. Here is a novelty ballpoint pen supported in the air by permanent magnets. It has no battery and the pen floats as high now as it did years ago. Looking at the whole picture, maglev with linear motors can transport a load using about one seventh of the power required by an airliner to transport the same load.


If we use linear synchronous motors in the guideways all of the cars will run at precisely the same speed at all times, and therefore the spacing between cars will never change. It will be virtually impossible for them to collide with each other. They will be like boxes on a conveyor belt; or like plug-in electric clocks that keep exactly the same time because they are all running synchronously on the same alternating current. In a dualmode system this will eliminate a huge number of proximity sensors, velocity-control systems and other parts, therefore LSM will greatly simplify the transportation system and increase its reliability and safety.


A nonprofit team, of which I am a member, has "invented" a dualmode system we call "HiLoMag". We have studied all of the various configuration choices and have arrived at what we believe to be the best combination. I would love to spend my time telling you all about HiLoMag, and naturally I would emphasize how superior it is. But as the last speaker in this conference I was asked to sort of wrap things up and to—quote "share my vision of dualmode travel in the 21st Century." Therefore I won't beat the drum for HiLoMag—except to hint that this team really likes maglev and linear synchronous propulsion.


At this time the recognition that we must have a dualmode system is much more important than the engineering details. There are several different ways of accomplishing most of the requirements, and time will tell which combination is best. So I won't wrestle with my dualmode colleagues from this platform, but I will argue that others, those proposing extensive single-mode transit systems, PRT or otherwise, are looking at the future much too narrowly and unrealistically. In a democracy we will never get very many people to stop driving their private cars, and we won't need to, even as the number of cars increases.

The single-mode transit people should join the dualmode movement, because that is the way transit service can be made much more available and much cheaper. And the automobile companies should get onboard dualmode, because they are going to be selling millions of dualmode cars.


Private cars are considered bad these days, and so is urban sprawl. But when we examine the basics we see that neither cars nor sprawl are inherently bad. The things that make both of them seem bad are pollution, fuel depletion, and traffic congestion. But these bad byproducts of cars and sprawl will be eliminated by a dualmode system. Both urban sprawl and private cars are basically wonderful, because they contribute to fulfilling life styles.


We can't simply continue patching the obsolete transportation systems we now have. The patches are obviously not working, because the situation keeps getting worse rather than better. More and more people see that none of the conventional things being proposed will do much good. Trains and automobiles are over a hundred years old; they were nineteenth-century inventions. They are obsolete. The only way to get high capacity and safe high speeds, keep the wonderful advantages of private cars, and also solve most of our transportation-related environmental problems is to design and build a revolutionary system for 21st century traffic and life styles using 21st century technology.


Since people won't give up their cars, and more people are getting cars, it doesn't help significantly to build more transit or new kinds of transit. Twenty-five years ago transit accounted for five percent of urban travel. Now, with car use almost universal, transit averages perhaps two percent. Earlier urban transit systems were financially profitable. Now subsidies pay most of their costs.


The bankrupt passenger railroads were taken over by the government in 1971. The Amtrak deficit has continued to increase ever since. Yet we talk about more trains as a solution to our traffic problems.


Jonathan Richmond of Harvard University recently released a comprehensive study that analyzed the performance of more than a dozen light rail systems built in the United States in the last twenty years. None of them were financially successful, and none of them even came close to achieving the riderships they had promised. Worst of all, there were very few light rail riders that were new transit riders. Three-quarters of the customers were former bus riders, and many of the bus companies then went out of business. None of these expensive light-rail systems had any measurable effect upon the traffic congestion. Yet light rail continues to be promoted. Don't our planners read?


You want to know how much our huge national dualmode system will cost. How the heck should I know? Twenty to fifty million dollars per mile of guideway. Hundreds of billions for the nationwide system. But note that unlike trains the vehicles will not belong to the guideway companies, so they won't be part of the system cost any more than the cost of the cars on our highways are considered part of the cost of the highway system. The guideway system will be paid for by automatically charging every vehicle that uses it (and essentially all vehicles will use it.) What will the guideway use fees be? Far less than the cost of gasoline transportation by then. The design and construction should be financed by government bonds. These will be safe bonds, because the market for guideway services will be enormous. Bond buyers will be making not only a financial investment but also an investment in their own future transportation.


Expensive? Yes, for the system, but not expensive to use. Bear in mind that it will be a universally used system, like our highways are. If we build a light-rail system or a PRT it will have to be heavily subsidized. But make it a dualmode system, with comparable costs per mile of guideway, and it will accommodate all of the private cars, buses, and freight. Its constant and high use factor will eliminate any need for subsidies. Guideway use will sell itself. Commuters stuck in highway traffic who see the adjacent guideway traffic flowing at a constant high speed will surely start using the guideways.


Since mass-produced automobiles became available the percentage of travel by transit and by railroad has steadily decreased, and more transit, new types of transit, and government pressures aren't going to reverse that century-long trend significantly. More highway lanes are not a satisfactory answer either. Dualmode transportation is the only answer that will really work. It is the answer because it combines the best aspects of both private transportation and public transportation, and of highways and trains, yet it reduces or eliminates most of their shortcomings.

With dualmode transportation things won't come to a halt when the world's petroleum is gone—and that will be gone very soon. Maybe you have noticed the price of gasoline lately, and the gasoline-price-related protests in Europe. It is going to get a lot worse. With only existing types of transportation, or with Automated Highway Systems, we could experience a repeat of the dark ages.


The dualmode transportation concept has been independently invented by a couple of dozen people—that we know of. Seven of them are in this room, including one from Denmark and one retired from the U.S. Department of Transportation. When a number of people independently think of the same solution to a problem it is a good indication that the need is real, that the proposed system is probably the right solution, and that it is time to implement that solution.

It is to the credit of the organizers of this conference, Kathy Mueller and Bill Flanigan, that they recognized the potential of dualmode transportation and included it in the program rather than consider it too radical, revolutionary, or crackpot. In other future-transportation conferences I have attended I was greatly disturbed to see that they were neither looking at the future beyond tomorrow, nor looking at any types of transportation system not already in use. Truly innovative or revolutionary transportation concepts were largely excluded.


Recently I heard a supposedly responsible leading transportation engineer say, "Dualmode systems are something that we should keep in mind for the future, but it is too early to think about such revolutionary ideas." Good Lord! Doesn't he realize that it will take at least a couple of decades to design and implement a dualmode system—or any other extensive system? By that time most of our oil will be gone, global warming will be worse, the air in some cities will be too thick to breathe, and I don't even want to think about the traffic jams by then. Instead of studying the real solution a high percentage of the transportation planners want to add more freeway lanes, put inadequate battery-electric cars on the highways and build more expensive transit systems that would be little used.


Several months ago I contacted a senior and highly respected Ph.D. in the Volpe National Transportation Systems Center of the USDOT on our need for dualmode. Let me quote a bit from his response.

"It is by no means clear that any entity exists with the authority to design and implement a true 'national' system, nor that agreement on its nature could ever be reached. Dualmode is a very different notion than the Interstate Highway System. It is hard to imagine the process by which a decision could be reached among the many necessary parties to commit to such a major and expensive undertaking. It is hard enough to simply widen a major highway. The mind boggles at just the time and cost of the environmental impact statements. I simply do not think that the right of way and environmental approvals for such a network could be obtained even if the funding were available."


The implication is that there can be no more revolutions in transportation—that we can't get there from here. But looking back, many said at the time that the railroads were impossible, as were the automobile and highway system, the airplane, and the jet airplane. Now that we have them these things seem quite possible. We will have further evolution in existing transportation systems, and we will also have a few more revolutions. A dualmode system will be the next big revolution in transportation.


But the political and sociological problems are overwhelming. We who propose dualmode are tempted to give up. But we can't give up, because somebody has to get the message across. I am eighty. Many of the other dualmode proponents are also elderly. We won't live long enough to use a dualmode system ourselves. We are trying to promote it so our grandchildren can use it—I guess. I hope the ball gets rolling soon so we old men can return to retirement. But this effort is a more useful challenge for me than anything else I can think of.


If a patient dies when there is no cure, that is sad but understandable. If there is a good cure but the patient dies because the cure wasn't used, that is irresponsible, frustrating, and maddening. I'm not a politician or a fighter. I hate discord and controversy. But I am urging the use of the dualmode cure, because the patient's many illnesses are close to terminal.


If you are swayed by what the other dualmode speakers and I have been saying, please do all you can to help—Write letters to the editors, argue with your boss, alert your congressmen and transportation officials; become a common sense dualmode transportation activist. Grass roots efforts can pay off, but remember that it takes a huge number of grass roots to grow a lawn. Some type of dualmode system is inevitable. The question is when will we have it? How long will we delay the decisions and further compound our huge problems?

Below is a list of dualmode transportation system proposals. This material is from the huge and excellent Innovative Transportation Technologies website established and maintained for educational purposes by Professor Emeritus Jerry B. Schneider, of the Department of Civil and Environmental Engineering at the University of Washington in Seattle. One part of the ITT website is devoted to the Dualmode Debate page which includes numerous commentaries from a variety of people from around the world who are working on this topic.  There a number of active dualmode inventors, including Dr Guadagno, Palle Jensen, Professor Schneider, and myself, who are working toward formulating agreements on the details of an optimum dualmode system.

Dualmode Systems under Active Promotion

Autobus - would carry cars on highways on transporters. (Bill Bowen)

Autoshuttle - a German concept that would utilize maglev technology to transport a variety of conventional vehicles in carriers at high speed (Krevel and Steingroever)

Autran - a system with carriers that would carry autos, passenger cabins and freight containers (Van Metre Lund)

Biway - (England) is similar in some ways to HiLoMag, RUF and Flexitrain (Jim Buick)

Carbus/PMT - uses large trucks on the freeway to carry conventional or small electric vehicles as well as bicycles and people (Dave Petrie and Andrew Frank)

Flexitrain - small, public, rental or privately owned electric cars that can be connected into trains for longer trips, being developed in New Zealand (Charl du Toit)

Higherway Transit Research - a suspended, dualmode PRT concept that shows great promise. (Tad Winiecki)

HiLoMag - personal cars, light trucks, transit, long-range buses, taxis, etc. on streets and national high-speed synchronous automated maglev guideways. (Francis Reynolds)

InTranSys (Integrated Transportation System) - a "skyhook" concept that shows how a variety of vehicles could be carried on suspended pallets, using a linear synchronous motor for propulsion. Cimarron Inc. (Richard Guadagno)

Japanese automated freight system - uses an automated guideway for long trips (no drivers) and conventional streets for final delivery (or pickup) - an Automated Freight application

MegaRail Transportation Systems, Inc. - a dualmode system that uses "carriers" to transport passenger or freight vehicles that is under development in Fort Worth, Texas. It has also been designed to accommodate vehicles that can operate on the guideway without a pallet. (Kirston Henderson)

Monomobile - a dualmode, suspended small vehicle system being developed in Cincinnati, Ohio (Jay Andress)

NAP (National Automated Pallet system) A 1979 proposal to the USDOT (Walt Velona)

RUF - a Danish dualmode concept that uses electric vehicles on conventional streets and a monorail-like automated guideway for longer, higher speed trips under full system control (Palle Jensen)

Station cars - there are French, Japanese and American efforts to devise some dualmode capabilities under this heading

Synchro-Rail - a dualmode concept that uses small electric cars propelled by linear synchronous motors, being developed in the U.K.

Transglide 2000(TM) - describes a bicycle transit concept that would utilize elevated, bike-only guideways.

Less Active-to-Inactive

National Automated Highway System Consortium - see the description at their Web site. The NAHSC is currently inactive in the U.S.

MIX - a small vehicle designed for neighborhood use that can also be suspended from a cable for longer, faster trips.

Pallet systems - describes work done at MIT several years ago on the development of pallets for use on an automated guideway, carrying vehicles and freight.

Segway - uses Smart Carts (pallets) on an automated guideway to carry a variety of vehicles.

Skybikes and Skytrains - describes a concept that combines bicycle and PRT concepts to create a dualmode, high capacity peoplemover.

Transmodal Capsule - a master's thesis done at the University of Washington in Seattle very conceptual but has stimulated a lot of interest.

UTI (Unified Transportation Initiative) - a concept that is still pretty vague in terms of technology - but the concept description is good as is a preliminary analysis of economic viability.


Last modified: August 31, 2002