Slashdot Mirror
New Thoughts in Public Transportation
Matthew Shaylor writes "The BBC has the following article about an ultramodern public transport system to be tested in Cardif. Unlike conventional public transport, this consists of small cars that running on tracks can automatically take themselves to the correct destination. This allows there to be a mesh of tracks and stations thoughout a city, as opposed to traditional transport which tends to run along corridor routes to a city center. An interesting paper is available. Future versions may have dual control to allow people to drive the cars from the nearest station off the track to their homes. A true replacement for the car!"
This is a concept commonly refered to as Personal Rapid Transit (PRT), a subset of Automated People Movers (APM) found at many airports. PRT has been around for a while and has somewhat fringe supporters (like me). Edward Anderson at the University of Minnesota has generated some of the most credible system designs and incorporated under Taxi2000. In fact, Raytheon developed a full test track of Anderson's concept outside of Boston; Bostonians can visit thier Marlborough, MA facility and see the future,!
The reason that PRT remains a fringe concept is related to economic challenges, not engineering ones. Although there are claims to the contrary, the general problem is that - like all public transit - PRT require a very high inital capital outlay. In dense urban areas, right-of-way costs are prohibitive. However, just as with information networks, public transit networks generate positive externalities: the larger the system, the more useful it is to everyone.
Furthermore there is little incentive to invest in expensive public works projects have prevented the testing of a fairly unproven technology. Public agencies would much rather invest in light rail systems that they have seen before than fancy driverless systems. Also, there is no conclusive proof that these decentralized systems can sustain the high corrider passenger/hour throughputs that make public transit so desirable for really dense urban areas.
Hopefully, projects like Cardiff will succeed and PRT will get recognition and legitimacy, but this is a technology that has been kicking around for a while and - as you can probably tell - is not insanely complex. As usual, economics and public policy get in the way of interesting engineering!
Urban Light Transport has more information on their web site, including some much higher-res images, FAQs and other info.
The most interesting (and not really mentioned) factor is that the automatic taxis don't travel on predetermined routes, they navigate their small network of paths to get to your destination.