Envisioning a Desirable Personal Transport System for the Future
by larens imanyuel
Below is an essay summarizing my concept of how advanced transport should develop, which I wrote at the request of Jerry Schneider. I see that an introduction is necessary, because the first sentence is at odds with the assumptions of most of the people on this forum. When I say that we need a long term "technology" roadmap, I mean exactly that. I think that the technology available for advanced transport is going to be fluid and continue to advance in important ways for many decades. This is quite different from the electrification of railways 120 years ago, which was a one-step process. Today San Francisco can run streetcars of all ages on the same route well as a tourist attraction, because the guideway has not changed.
This fluidity of technology leads to a problem, "How does one fix the standards for a guideway to best insure compatibility with the next generation of available technology, so as to minimize the risk of rapid obsolescence?" To the extent that they do not see a good solution to this problem, transport innovators are largely backing nonguideway solutions, e.g., robotic automobiles. MAIT is backing a more conservative engineering approach to multimodal transport than I am, yet the pictures on their website still show a state of exploration, rather than a completely unified approach: http://www.maitint.org/projects
In making their replies to this essay, people should first address the larger development questions involved. Most of the details of the different approaches have already been aired on this forum.
Multimodal Personal Transport (MPT) Roadmap
To best use new technologies in automation, electrification, and materials in the creation of a superior transport system, we need to use a technology roadmap with at least a 50 years time horizon. The emergence of new industrial miniaturization technology, loosely called "nanotechnology", will maintain our historical trend toward greater specialization in goods and services, which in turn is going to maintain the demand for yet faster intercity transport. This will exceed the capabilities of conventional automobiles, trains, and airplanes, which can no longer continue to support a doubling in average travel speed about every 25 years. This same emerging technology, however, will allow us to create a multimodal personal transport (MPT) system that will dramatically expand our transport capabilities in the 21st century without exceeding our resource base.
MPT will be a true personal transport system with small, lightweight vehicles designed mainly for the travel of one person alone, but with a large enough rear space to comfortably carry an additional medium size adult or an equivalent load of children, pets, tools, luggage, or other cargo. These vehicles will thus be able to satisfy the large majority of demand for transport, including fast freight. The resources not spent on matching the large sizes of conventional automobiles will be available to create faster, more economical, and safer modes of travel. The modest speed of the primary MPT vehicles will be augmented by latching them to different types of carriages, each specialized to run on a different guideway or in a different environment. Switching to these modes will be rapid, because no reloading of passengers and cargo will be necessary.
The four dominant modes of today's personal long distance travel will correspond to the four main MPT modes as follows:
1) Taxi - Automating taxis will replace the high labor cost of drivers and allow children, disabled, and the elderly to travel freely at an affordable cost; at first these will run fairly slowly on segregated right-of-ways, but speeds will increase as reliable robotics become available.
2) Personal automobile - Semiautomatic mode will increase safety by putting automated restraints on poor driving; this is the same technology being developed for conventional automobiles.
3) High speed train - Relatively inexpensive elevated guideways will allow MPT travel at 200-280 kph (125-175 mph) without the high cost in time of traveling to and from, and of stopping at train stations, which is inherent in train travel.
4) Jet airliner - Transport in maglev pressure capsules traveling in a vacuum will allow faster cruising speeds at lower costs than with jetliners; at 1g acceleration MPT vehicles could reach 2000 kph (1250 mph) within one minute and 16 km (10 mi), giving access costs a small fraction of that with conventional airports.
Additional land, water, and air modes will allow convenient access to remote areas at somewhat higher cost than with the main modes.
The general development of the four main MPT modes will go as follows:
1) Design, testing, and promotion of "1+" passenger MPT vehicles to insure that the designs used represent the best concepts for the long term safety, speed, economy, and flexibility of transport.
2) Increasing automation of conventional automobiles to increase roadway capacity sufficiently to allow the introduction of different lanes for different width vehicles - nominally one person wide MPT, compact conventional automobiles, and full highway width vehicles. Lanes will be filled so as to further increase capacity, and will enhance safety by largely segregating different sizes of vehicle. Giving priority to narrower and more automatic vehicles will promote their use, thus increasing yet further roadway capacity and speed.
3) Introduction of high speed elevated guideways, associated high frequency/DC electrical distribution systems to power them, and auxiliary fuel systems designed to be transported safely on MPT. This new energy technology will be available as a superior energy technology throughout the entire economy.
4) Development of guideway networks large enough to be widely available for transport. Ultralight personal vehicles, e.g., small bikes and microscooters, will be used to temporarily augment network coverage. Minimal networks two to three times the current length of superhighway networks should be adequate to eliminate most congestion on current arterial roadways.
5) Introduction of transport in vacuum tunnels and tubes. This will require the development of economical tunneling, construction, and maintenance equipment, as well as solving the safety problems associated with this very high performance mode of transport.
6) Expanding the networks of main modes, introducing auxiliary modes, and generally improving the performance, and decreasing the costs of the overall system.
7) Completion of transcontinental links that will make the network a truly global system.
This Multimodal Personal Transport Roadmap, besides greatly enhancing our transport capabilities, will be coupled to advanced technologies in other sectors. It will thus help channel our scientific and engineering resources into advancing productivity throughout our economy over the next half century.
Why PRT has only a limited role in the MPT Roadmap Concept
If Personal Rapid Transit (PRT) is so revolutionary, why have not more people than the true believers gotten behind it in the last forty years?
I think that the idea of PRT has been constructed in such a way that it represents a return to a former idealized way of life, the pre-automotive, compact, pedestrian-friendly" neighborhood in which people readily interact with their neighbors during their daily travels.
Telecommunications and faster transportation, however, have largely replaced the social forms of this past era with more "modern" social forms. The rule is, "you can't go home again", so efforts, e.g., "smart growth" and "transit-oriented design" fail to generate more than a few token examples, even though they gain wide lip service.
In formulating PRT this way its advocates become elitist. While perhaps it is a good idea to "gentrify" old compact neighborhoods with PRT and to build some new PRT oriented ones, it is elitist, if this PRT is built to the exclusion of the aspirations of the rest of the population. To make my point I will use the definitions and characteristics of PRT in the paper, "The Case For Personal Rapid Transit", by Joerg Schweizer, et al, on the ATRA website: http://www.advancedtransit.org/doc.aspx?id=1129
Joerg points out that automotive infrastructure uses about 30% of urban land, and up to 70% in cities like Atlanta and Los Angeles. He does not say what an appropriate amount of land use would be. Assuming that 15% is desirable, based on the amount of resources people typically devote to transport, a reduction in the size of automobiles, an increase in road capacity by automatic controls, and an increase in average parking density through automatic and remote parking could easily provide the twofold decrease in infrastructure land use for the typical city. Joerg suggests that the total right-of-way segregation, mainly through elevated guideways, and the total use of publically shared passenger vehicles. i.e., PRT, in combination with "compact, pedestrian friendly neighborhoods" is the answer to the excess use of urban land by automobiles.
While this may be a good solution for the densest cases, it ignores the fact that the other solution to the problem is to decrease urban density while increasing the speed and capacity of major transport routes. This other solution is just a continuation of the trend set by modern forms of transportation. It makes nature far more accessible to the general population, which is generally strongly desired, though proper land use to provide good access while preventing environmental abuse needs to be a major part of urban plans.
Joerg mentions 40/kph (25 mph) speeds at an ideal guideway spacing of 0.8 km (0.5 mi), saying that this is faster than most arterial streets. If the time spent walking to stations is included, however, the average speeds are going to be about the same as nonexpressway automotive door-to-door speeds. He mentions the increased safety of not having automobiles on local streets, but fails to mentions the increased problems of weather and personal security during walking, which for most people outweigh the advantage of removing automotive accidents.
He mentions an energy savings of 60%, but fails to mention that energy efficient automobiles are also capable of such savings. He says that PRT can be connected in integrated networks, but fails to observe that PRT has ZERO chance of being made into an effective integrated network, if it can only match the performance of the automobile, which already has a thoroughly integrated network.
Joerg mentions a cost of $6-8 million per km ($10-13 million per mile) as "affordable in medium and lower density areas". The only areas that are going to be able to afford these prices compared to arterial streets are older, higher density, thriving metropolitan core areas, where there has been a run up in land prices because of a lack of good transport to lower cost, peripheral metropolitan areas. Alternative advanced transport designs with the higher speeds and capacities needed to provide that good, longer range transport will reduce the core land values below what will economically support complete grade separation of transport. On the other hand, they will raise land values in the peripheral areas.
What we really have is a conflict of interest over real estate values that would best be dealt with by political action concerning taxation and land use policies. The elitism to which I alluded is really that of the elites of the established metropolitan core areas, who have well-established propaganda networks to push smart growth, transit-oriented development, and perhaps PRT, while failing to mention the larger picture. They do not have the votes for their limited agenda, however, so their propaganda largely serves to stagnate effective advanced transit design.
PRT with the characteristics that Joerg gives cannot possibly form an effective large metropolitan network, because its speed and capacity are at least severalfold smaller than alternative designs with the same cost. He mentions its safe "brick wall" stopping design, but fails to mention that this will make it immediately noncompetitive in capacity with any alternative, including the automobile, that is not restricted by this feature. He mentions that strictly no PRT has been implemented, but does include Morgantown and ULTra as "PRT" in his captions. The Morgantown GRT should be classified as a variant of the high cost APMs, with almost no significance for economical advanced transport design.
ULTra is really an automated automobile running on a curbed roadway, which barely qualifies as a "guideway". It really should be classified with other low-speed, short-range automated variants of automobiles that are not capable of running on a high speed guideway. Thus there is really NOTHING happening with PRT, other than feasibility studies by its proponents. For the reasons I mentioned above, there is also no reason to believe that anything more will happen with classical PRT than has happened in the past.
Last modified: July 11, 2006