Logan’s Drive

A new take on an old transport concept might finally be adopted.

Tel Aviv PRT

The city of Tel Aviv has grabbed headlines and the imagination of futurists everywhere with the announcement that a so-called “hover car” passenger transport system will be implemented by the end of 2016 on a trial basis.

Slim elevated tracks will have sleek pods hanging underneath, suspended from a rail that uses magnetic levitation to keep the supporting hook above the rail, and using linear motor technology to move the pods forward. Travelers will go up to elevated stations where they can call a pod like an elevator. When a pod arrives, passengers get in, shut the door and select their destination. There is no need to drive, or even stay sober, since the system is totally automated. Pods coming from behind will automatically slow down, in theory resulting in better flow since there is no stop-and-go braking that occurs in conventional traffic.

There are also environmental benefits such as lack of noise or pollution from internal combustion engines, and less space wasted by parking the vehicles in cities. The fact that there is no wheeled physical contact between the rail and the vehicle means major gains in efficiency. Pods moving in the same direction at the same time can be grouped together for even more energy savings. The safety advantages over automobiles are obvious.

The concept of Personal Rapid Transport (PRT) is not new. The idea is to combine some of the convenience of the private car with the advantages of a train. Instead of sharing a large vehicle that has to be stopped at regular intervals to embark and disembark fellow passengers, the PRT journey is non-stop and hence considerably faster. Frequency of service is less of an issue since it is on-demand, so the system works based on the needs of the passengers rather than passengers building their schedules around the convoluted operational logistics of the system. The use of smaller and lighter vehicles means lighter duty rail infrastructure that is cheaper and potentially less obtrusive than the likes of the elevated tracks of Chicago or New York. The lower cost per mile of the network should in theory make it easier to build more extensive networks reaching more nodes than a conventional mass transit system.

Various attempts at PRT prototypes have been proposed and built in the past, some resembling small bubble-shaped pods running on a rollercoaster-like rail system. Perhaps the most extensive study was carried out in Hamburg in the 1970s. Cabintaxi was a network of elevated tracks using a clever arrangement that had cube-shaped pods suspended underneath the track going in one direction, and other cube-shaped pods sitting on top of the track going in the other.

Over several years the experiment logged thousands of journeys in various conditions and remains the most extensive PRT study ever carried out. Installation costs were found to be less than ten percent of a subway system over equivalent distances, and a full feasibility study cleared the path for implementation of a thirty-mile (48km) system throughout Hamburg. However the project was discontinued in 1979 for budgetary reasons and it never saw commercial service.

An experimental system called Ultra Global PRT which uses rubber-wheeled pods on a concrete guideway was trialled on a 0.6 mile (1km) track in Cardiff, Wales, in 2001. The concept was proven and is now used at Heathrow Airport’s Terminal 5, with another planned for India where the Amritsar Golden Temple, a sensitive site where internal combustion engines are banned, will be connected to the local airport.

Since 1975 the Morgantown Personal Rapid Transit in West Virginia has connected the center of the city with the three campuses of West Virginia University, however this is not considered true PRT since the vehicles are closer in size to the larger people movers in use at many airports, and hence are more like a small bus. The construction of this, and the Cabintaxi system in Hamburg, was part of a mini PRT craze that came about as a result of the publication of the HUD Reports by the Urban Mass Transportation Administration (UMTA) under the US Department of Housing and Urban Development (HUD) in the 1970s. This series of studies in mass transit concepts led to numerous commercial enterprises conducting research in the area, but political change in the late seventies diverted funding to other causes.

The fact that any operational PRT systems, like other novel transport systems, can only be found in closed and controlled environments like airports indicates that the concept has had a hard time finding acceptance in the street. How well PRT fits into the city depends a lot on what lies beneath the rails. Elevated urban freeway structures are often a source of noise and urban blight, with nothing but dereliction and homeless encampments settling underneath. Elevated commuter train tracks in cities are not exactly discreet, but city dwellers are used to them and they have become part of the landscape.

The success of the PRT system slated for trial in Tel Aviv will depend a great deal on the public’s acceptance of its aerial structures. If it passes over existing roads, rivers, and other assorted fixtures rather than having derelict empty areas underneath, then it should not be a problem. However the public can be finicky about accepting new and unfamiliar objects on the landscape. People who object to the “eyesore” of wind turbines would scarcely notice the arguably much less attractive strings of electricity pylons that criss-crossing the land. Asterix, a children’s fictional comic book character set in Roman France, once walked past the construction of a large multi-arch Roman aqueduct traversing a valley and lamented “The Romans are ruining the landscape with all those modern buildings.”

PRT has had many false dawns in the past. Time will tell if the concept is finally ready for widespread adoption and acceptance.

Published in Forásach, July 2014