Personal Rapid Transit

From Wikipedia, the free encyclopedia

Personal rapid transit (PRT), also called personal automated transport (PAT) is a public transportation concept that offers automated on-demand non-stop transportation, on a network of specially-built guideways.

The first public PRT installation, ULTra, is currently under construction at Heathrow Airport in London, and scheduled to open for public use in 2008.

PRT is a system of small vehicles under independent or semi-independent automatic control, running on fixed guideways. The idea attempts to address a number of perceived weaknesses of public mass transit including fixed timetabling, limited routes, and sharing travel space with unrelated travelers.

In 1988, The Advanced Transit Association (ATRA), a group which advocates the use of technological solutions to transit problems, published a definition for PRT as follows:

* Fully automated vehicles capable of operation without human drivers.
* Vehicles use a reserved guideway.
* Small vehicles available for exclusive use by an individual or a small group, typically 1 to 6 passengers, traveling together by choice and available 24 hours a day.
* Small guideways that can be located aboveground, at ground level or underground.
* Vehicles able to use all guideways and stations on a fully coupled PRT network.
* Direct origin to destination service, without a necessity to transfer or stop at intervening stations.
* Service available on demand rather than on fixed schedules.

Proponents say that the low weight of small vehicles has the important benefit of allowing smaller guideways and support structures compared to other mass transit systems like light rail, translating into lower construction cost, smaller easements, and less visually obtrusive infrastructure.

The concept has been independently reinvented many times since the 1960s. It is considered controversial, and the city-wide deployment with many closely-spaced stations envisaged by proponents has yet to be constructed.

Past projects have failed due to lack of financing, cost overruns, regulatory conflicts, political issues and flaws in engineering or design.

From 2002–2005, the EDICT project, sponsored by the European Union, conducted a study on the feasibility of PRT in four European cities. The study involved 12 research organizations, and concluded that PRT:

* Would provide future cities "a highly accessible, user-responsive, environmental friendly transport system which offers a sustainable and economic solution."

* Could "cover its operating costs, and provide a return which could pay for most, if not all, of its capital costs."

* Would provide "a level of service which is superior to that available from conventional public transport"

* Would be "well received by the public, both public transport and car users."

The report also concluded that, despite these advantages, public authorities will not commit to building PRT because of the risks associated with being the first public implementation.