Proponents of personal rapid transit systems have frequently promoted themselves as opponents of traditional public transportation. Unlike expensive metro or light rail systems, they claimed, their PRT lines would be cheaper to construct, more convenient for passengers, and more attractive for users. Now that a new line is readying for opening in the United Kingdom, the technology may attain new prominence.
Over the years, most attempts at implementing PRT have failed due to a lack of interest from investors — and as a result of deceptive, dishonest campaigns by “pod people” who simply promise too much.
Even with the rebirth of modern rail systems over the past few decades in the United States, PRT continues to be brought up as an environmentally friendly solution for urban transport, allowing passengers virtually instant access to vehicles, stop-free commutes, and direct access to many destinations. In other words, it theoretically can solve many of the deficiencies of regular transit, which requires waiting for trains or buses to arrive, multiple stops along a route, and a walk or drive to and from stations. Yet only in 1975, at the University of West Virginia in Morgantown, has a system that allows such on-demand travel by automated train been constructed.
Next spring, London’s Heathrow Airport will take a step forward to advance the PRT concept with the implementation of a new network connecting its Terminal 5 and associated parking areas. The ULTra (Urban Light Transit) system is being developed by Bristol, England Wales-based Advanced Transport Systems and will initially travel between three stations along a three-mile track using 21 four-passenger vehicles. The mini-cars, which travel at speeds of up to 25 mph and which use lasers for guidance along the 7 foot-wide pavement, have tires and are autonomous, meaning they more closely replicate the experience of automobiles than trains. They’re battery driven and use energy at the equivalent of 200 mpg.
Vehicles are designed to bypass stations, allowing non-stop travel. Customers will pick their destination by pressing a button on a touch screen before departing. Empty vehicles will be available at all times at stops for passengers needing to get between the car parks and the airport terminals, or vice-verse.
The system didn’t come cheaply — at $41 million, the private airport owner that paid for the line and some of the technology’s development is making a big bet that it hopes to eventually expand throughout the airport and into the surrounding areas with 400 pods at a cost of $330 million. That is, if this first test goes well.
If the claimed $7-15 million costs per mile (without rights-of-way) are to be believed, this PRT is cheaper than normal transit, but not much. Per passenger, its costs may actually be higher, since it is only expected to handle about 500,000 annual passengers, an average of less than 2,000 a day.
Nevertheless, the system holds promise: its use of batteries installed in each vehicle rather than an electrified third rail or catenary makes the corridor easier to maintain and cheaper to build — an advantage that will soon be replicated in the implementation of similar technology on tramways. The use of electricity rather than diesel motors (as in the existing buses used by passengers) will eliminate local-source pollutants and decrease noise levels. The elimination of human drivers will improve travel times by 60% and reduce operating costs by 40% — if initial estimates prove accurate. Passengers will get direct and instant access between parking lots and the terminal; plus, they’ll eventually be offered similar service to surrounding office buildings and hotels.
Unlike the cities in which PRT lines are usually proposed, this airport environment provides a sealed-off, protected setting in which to experiment with this model for a new form of transportation. The ULTra project seems highly likely to operate problem-free here, but what is the appeal elsewhere?
Abu Dhabi is planning a new city called Masdar that will not allow cars and instead rely on PRT lines to connect people from one place to another; San Jose is planning a people mover between its airport and surrounding transit stations and neighborhoods; other American cities like Mountain View and Ithaca are “studying” the idea, though there are no definite plans there. Companies such as SkyCab and Vectus are planning their own rival PRT technologies to spread around the world, and unlike some previous PRT pushers, they seem truthful in what they expect to provide (in other words, they don’t claim that initial capital costs will be paid back with fare revenue).
For airports and new cities, PRT could supplement other mass transit systems rather effectively and encourage people to live car-free lifestyles by providing them destination-to-destination service with minimal walking to and from stations. In newly built environments, PRT could be constructed cheaply and it could be installed in such a way that does not disrupt its surroundings. Proponents use this fact as evidence for the universal applicability of PRT, claiming that it should replace transit systems since it would allow for the phase out of cars, but their arguments are weakened by the realities of the way cities work.
PRT cannot replace light and metro rail systems, as its capacity is far lower. Along major routes at peak periods, systems that are capable of carrying hundreds of people per train every two minutes are necessary, and PRT will never allow that kind of operation.
Similarly, if a PRT vehicle sounds awfully like an automated car, the analogy isn’t far off: indeed, the idea that people would be able to travel by themselves from one place to another is simply an advanced version of the car sharing systems now being implemented in places like Paris. Most major cities have serious transportation needs along heavily traveled lines, and PRT will not be able to do much there, since the lines would be completely overloaded and therefore unusable if implemented in very dense cities like New York or San Francisco.
In addition, PRT’s proponents ignore the fact that their calls for dense networks of lines and stations would duplicate the already existing road system and degrade the urban landscape with elevated structures. This is no effective already to urban sprawl, since direct access to PRT stations every few blocks would undoubtedly encourage the sort of spread-out environments that have blighted American cities for decades. For those that don’t care about that problem, a cheaper alternative might be to wait a decade or so for more advanced automobiles that can negotiate existing streets without drivers. Stations wouldn’t be needed for such a system — people could simply call an automated service, and a robotized car would arrive in front of the house. This is no less a fantasy than the installation of hundreds of miles of PRT tracks above city streets.
This experiment at Heathrow Airport, then, will test some of the basic arguments of PRT advocates and probably verify many of their claims about the system’s effectiveness, but it won’t provide a solution to the deeper problems with the idea.
Note to readers: Discussions of PRT frequently produce angry debate. There’s nothing wrong with spirited interchange, but let’s try to restrain ourselves from personal insults. They are not acceptable here and will be deleted. Image above: ULTra in action at Heathrow, from Advanced Transport Systems Ltd