Automated guideway transit

[3] The vehicles are often rubber tired or steel wheeled, but other traction systems including air cushion, suspended monorail and maglev have been implemented.

Buses could be easily introduced in these areas, but did not offer the capacities or speeds that made them an attractive alternative to car ownership.

Cars drive directly from origin to destination, while buses generally work on a hub-and-spoke model that can increase trip times.

AGT systems, and the personal rapid transit concept (or "dial-a-cab"), became a major area of research after the publication of the HUD reports in 1968, and subsequent funding by the US Department of Transportation.

Expecting widespread deployment of PRT systems through the late 1970s and 80s, many of the major US aerospace companies entered the AGT market, including Boeing, LTV and Rohr.

Although the mass transit world showed a lack of interest, AGT systems quickly found a number of niche roles that they have continued to fill to this day.

The Getty Center in Los Angeles uses a unique vertically oriented AGT to bring visitors from a parking lot off Interstate 405 to the Center at the top of a hill in Brentwood; this system places the motor outside the vehicle at the top of the guideway to reduce the weight lifted up the hill and thus improve efficiency.

Over time, the aerospace firms that had initially designed most of these systems left the industry and sold off the AGT divisions to other companies.

The Véhicule Automatique Léger (VAL) system in Lille, France, opened in 1983, is often cited as the first AGT installed to serve an existing urban area.

Larger scale INNOVIA advanced rapid transit (ART) systems in Toronto, and Vancouver followed in the next few years, and then the Docklands Light Railway in London.

For instance, the Vancouver SkyTrain started operations in 1986, but has expanded so rapidly that its track length roughly matches the Toronto subway which pre-dates it by 30 years.

London Heathrow Airport has installed a PRT system, known as ULTra, to connect Terminal 5 with the long-term carpark; its full operation began in September 2011.