Personal rapid transit (PRT), also called personal automated transport (PAT) or podcar, is a public transportation concept that offers on-demand, non-stop transportation, using small, independent vehicles on a network of specially-built guideways. Several different designs have been proposed, and as of 2008, at least one, a pilot project at London Heathrow Airport based on ULTra, is under construction. A quasi-PRT network, the Morgantown Personal Rapid Transit of West Virginia University, has been operational since 1975.
Most mass transit systems move people in groups over scheduled routes. The initial waiting wastes passengers' time. Scheduled stops waste both energy and passengers' time by slowing and accelerating passengers and vehicle-weight bound for other destinations. Personal rapid transit systems attempt to eliminate these wastes by moving people nonstop in small groups using small automated vehicles. The PRT acronym was introduced formally in 1988 by The Advanced Transit Association (ATRA), a group which advocates the use of technological solutions to transit problems, although the concept was not defined by ATRA.
Some of the key concepts of PRT have been toyed with since before the 1900s, but modern PRT really began around 1953 when Donn Fichter, a city transportation planner, began research on PRT and alternative transportation methods. In 1964, Fichter published a book, which proposed an automated public transit system for areas of medium to low population density. In 1966, the United States Department of Housing and Urban Development was asked to "undertake a project to study … new systems of urban transportation that will carry people and goods … speedily, safely, without polluting the air, and in a manner that will contribute to sound city planning". The resulting report was published in 1968, and proposed the development of PRT, as well as other systems such as dial-a-bus and high-speed interurban links.
In the late 1960s, the Aerospace Corporation, an independent non-profit corporation set up by Congress, spent substantial time and money on PRT, and performed much of the early theoretical and systems analysis. However, this corporation is not allowed to sell to non-federal government customers. In 1969, members of the study team published the first widely-publicized description of PRT in Scientific American. In 1978 the team also published a book.
Among the handful of prototype systems (and the larger number that exist on paper) there is a substantial diversity of design approaches, some of which are controversial.
The Ohio, Kentucky, Indiana (OKI) Central Loop Report compared the Taxi 2000 PRT concept proposed by the Skyloop Committee to other transportation modes (bus, light rail and vintage trolley). In the Taxi 2000 PRT system, the Loop Study Advisory Committee identified "significant environmental, technical and potential fire and life safety concerns…" and the PRT system was "…still an unproven technology with significant questions about cost and feasibility of implementation." Skyloop contested this conclusion, arguing that Parsons Brinckerhoff changed several aspects of the system design without consulting with Taxi 2000, then rejected this modified design. Despite the report's concerns regarding the implementation obstacles of PRT, the report did conclude that compared to the other alternatives, PRT offered the most acceptable point-to-point travel times, the most reliable service levels, the highest level of frequency of service and geography coverage, and was most able to maintain schedule. The report further concluded that, compared to the other alternatives, PRT would have over 3 times the ridership of the next closest alternative, including new transit riders over 9 times higher than the next closest alternative.
For More Information: Personal Rapid Transit (PRT)
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