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I prefer the similar system Skyweb Express (Taxi 2000). It uses a 3 person car, which is the minimum that with any sized group of people >1 no one would have to travel alone.

http://www.taxi2000.com/

These cars and lines are small enough and light enough to be attached to buildings or even run through the buildings themselves (no emissions, minimal vibrations due to rubber tires, etc.)

Elevating one of these things could cast about as much shadow as a telephone pole if the power lines made a solid surface. (maybe a foot or two high (sans car)).

Elevating a multi-ton train, even light rail, requires a lot of clearance and a robust track. The elevated train in Chicago takes up a 4 lane street worth of space (huge platform) for the multiple tracks in some places downtown. PRT would not have this problem since the individual cars can be simply attached to the buildings, or could be elevated on a track not much wider (or heavier) than roller coaster tracks. Additional tracks like the "through" lanes on freeways could be added for additional capacity with a very minimal outlay in ground clearance. A couple of telephone poles in the shape of a triangle with a brace is about as much support these would require (in general).

These cars are powered by electric induction motors (think of the old track cars toys from the 80's but with better motors, rubber tires, and enclosed tracks), there is very little impact footprint involved with them in total. (and the tires would last quite a while due to not being used much for sudden stops / starts / slips on asphalt / concrete.

My father has been working closely (and is an investor) in one of the PRT systems called taxi2000 (not sure how active the project is at this point) and the vast vast vast majority of their issues getting these systems installed, tested, and in-use on a wide scale is political backrubbing by existing transit authorities attempting to extoll the "virtues" of their systems. There is a phenomenal amount of money wasted in light rail / bus line funding.

I don't remember the exact numbers but the "track" these cars operate off of is a magnitude cheaper than even light rail, and has a necessary minimum clearance in the measure of inches instead of yards for passing around or through obstacles. The light rail in Minneapolis that was laid down recently is a perfect demonstration of cost overruns, schedule overruns, interrupted service (and road travel), etc. inherent in the sort of ridiculous attempt at installing rail.

More information on the system (with included videos and such) is found at: http://www.taxi2000.com/

The basic gist here is that the PRT / taxi2000 systems could very well actually MAKE money for a city employing such a system since it has such cheap operational costs. No other mass transit system could claim to get anywhere even close. All other mass transit systems widely in use are publicly subsidized all of the time in some manner.

- Toast

P.S. My last light rail travel (on that newer light rail line in Minneapolis) was quite unpleasant; loud (screeching metal) tires, crowded (and hot) train, lots of stops for bridges / ferries / traffic intersections, infrequent stops (because train platforms are freaking huge and cannot be placed frequently along the route), etc. I hope the idea that light rail is "green" for anything other than point-to-point mass transit for high volumes (between cities, or between airports / stadiums / downtown areas / other mass transit hubs) dies like the horrid idea it is. Light rail is really not light at all compared to these PRT systems.

Close to 100% full? I don't have any figures to dispute this, but somehow I doubt you have any to prove it either. In the example I used above (1 big diesel engine vs lots of little petrol motors), 50% occupation would still have been at least as efficient as having a car for every two passengers

The fact that this example used combustion engines is irrelevant. I could have illistrated the same point with a large electric bus (say, 400kw motor) vs many small electric cars (say, 75kw motors). Energy is energy. The point I'm making as about the economy of scale you get with one big, powerful vehicle that moves many people vs many little vehicles that move a few people each.

Railways are cheaper to build than roads. And they are a more efficient way of making contact with the ground (narrow wheels), which means less drag.

I'll concede that the "on-demand" nature of having pods ready to go when you are ready to go is more convenient and may save passengers the 5 or 10 minutes they would otherwise have to wait for a bus

The more I reread your post, the more I am convinced that it is a subtle troll. I mean the wrong statements that nevertheless have a certain crazed right of logic to them: "If the roads are too crowded, build bigger roads" and "Cars ... are the most economically efficient solution"; coupled with the emotional appeal to the rugged American frontier spirit that is so woefully inappropriate to the modern urban world: "I want a back yard. The bigger the better."

Then there are inflammatory statements "stupid things like the Big Dig in Boston.", an absence of any evidence for your claims, and finally a disregard for technical advancements such as this: http://taxi2000.com/ http://faculty.washington.edu/jbs/itrans/prtquick. htm

This gets +5? Our moderators are not on the ball today.

You mean something like this?
http://taxi2000.com/

It's basically your own personal train that takes you non-stop to your destination.

I don't see why everyone wants to see more trains/subways in cities. They just seem like large busses that are restricted to rails. Their passengers still have to make numerous stops before they reach their destination, plus they claim to be much cheaper than the subway, bus, and light rail.

You mean something like this?
http://taxi2000.com/

It's basically your own personal train that takes you non-stop to your destination.

I don't see why everyone wants to see more trains/subways in cities. They just seem like large busses that are restricted to rails. Their passengers still have to make numerous stops before they reach their destination, plus they claim to be much cheaper than the subway, bus, and light rail.

• Small (3-person) elevated train cars mean small tracks, not a lot more expensive than road -- being elevated means you don't need much right-of-way.
• Off-line loading means relatively high capacity, again like a road (and unlike light rail or other mass transit) -- moving lots of low-capacity vehicles can carry more people than a small number of high-capacity vehicles, and unlike on a subway you only stop for your destination, not other people's.
• Cars that go directly to your destination means no time waiting to make transfers.
• Automatic interchanges (that look like a highway cloverleaf, as opposed to traffic signals) mean that dense and decentralized networks won't slow the system down. One-way tracks that make relatively tight loops mean simpler tracks and interchanges, while making it possible to cover an area more densely.
• And again because entering and exiting the vehicle occurs offline (i.e., not on the main track), frequent stations won't slow the system down (as they would with mass transit).

It consists of small (1-4 passengers) elevated subway cars on a network of tracks. Passengers could ride alone or with friends, and each car could go to every station without stopping. So you'd walk to the station nearest you, wait a minute or so for a car to arrive, and go directly to the station nearest your desitination.

Major traffic centers (e.g., malls, hotels, office complexes) could have stations inside the building.

So far, Taxi2000 seems furthest ahead on the tech aspect. No, I don't own stock. I tried to buy some, but the company is selling only to large investors.

Personal Rapid Transit, IMO, is the future. You can see some of it at Taxi2000. I don't like how some of the prototype's look (look flaky, cheap) but it's on the right track. (no pun intended)

There exist quite a number of PRT systems that could give us car free cities.

I think Taxi 2000 has the most mature concepts.
The Ultra concept is also interesting, mostly because it
can make some use of existing streets. They also have a neat test track.

There is actually a concept similar to this being designed as we speak. Look at http://www.taxi2000.com/ . You go to a station, buy a ticket from point to point, the car seats 3 passengers, it takes you the most direct way it can.

You always see renditions of society in the future. No Gas/oil cars, advanced personal transportation (i.e. PRT), advanced community topologies, advanced technology etc.

Communities/Cities are totally un-organized. All we do is build over them or around them. They need to be trashed and start over, rebuilt from the ground up. Build using current technological advances; including an Internet layer, LANs etc.

We need a President who is willing to rebuild society for a new age. Is Steve Jobs right for that? I dunno, I doubt it. No doubt Steve has been thinking how to improve the US while designing his products. Though, I'm sure he'd be kind of bias and try to implament nation wide technology based off Apple INC.'s ideas and goals.

If you haven't heard, the was banned in San Francisco. Ouch.

The judges claim they banned it because it is "unsafe for city sidewalks", but they also commented that the Segway is "a national threat at least as grave as Iraq" because of laziness. I don't think Iraq is that dangerous, so I don't know exactly what that comment is suppost to mean =) Also they said they didn't want to see a "potential tsunami of lard".

Personally, I don't think Segway is the "future of transportation". I'd much rather see PRT everywhere in the future.

Problem already solved. Many tracks. Main problem is the stations are so expensive (price is cheaper if the elevator and its cost is shared with neighboring buildings which can take advantage of the wheelchair accessibility and the second-story business space around the station -- some cities such as Minneapolis have the second floors woven together like a huge mall due to enclosed pedestrian bridges).

One reason public transportation turns many people off is that you have to stop at every station/bus stop along the line. This greatly exaggerates the time it takes to get anywhere. Even when I ride on the transit systems that are considered successful (NYC, Chicago, Boston, DC), I spend at least half of my "travel time" on a bus, a train, or a bench that isn't moving. These public transit systems simulate traffic jams very well.

I like the idea of a personal rapid transit system like Taxi 2000. Something like this is dirt cheap to build when compared to light rail and monorail, intrudes less into existing infrastructure, and travelers don't make any stops until they reach their destinations.

A fresh approach like this would appeal to more people than another elevated train or subway system. I live north of Seattle so I couldn't vote against the monorail, but it makes me sad that so much money will be spent on a transit system that is 40 years out of date before construction even begins.

Seattle has a reputation for being cutting edge. They invented Starbucks and grunge. They flew 707s upside down in public. The monorail measure is an excellent opportunity to make some real progress in public transportation and set new horizons for every other city on the planet. Instead of taking the risks, I'm afraid some gutless, powermongering bureaucrats are going to follow the path of least resistance and build us a brand new, out-of-date behemoth that nobody will ride.

Maglev, monorail, and lightrail all have the same fundamental problem. They are just glorified trains. They must stop at every stop, increasing travel time. They must cram passengers during peak times, making it less appealing than driving alone in an airconditioned car with your own music. They are horribly expensive, causing taxpayers to pay through the nose to subsidize it to keep it alive. They are terribly inefficient, since they run whether they are full or empty.

No transit system (even a snazzy one with mag-lev) will ever be successful unless it includes the following:

• Point to point service (no transfers)
• On demand service for little or no waiting time.
• Fares competetive or lower than traditional transit and automobiles
• A profitable business model (!)
• Faster average times than cars
• Privacy to travel without sitting crammed next to strangers

But until politicians and citizens in the US catch the vision, we will continue to suffer from congested freeways and inadequate mass transit.

• 1. Get on Board! Public Rapid Transit
  1. Taxi 2000

The main problem with Skytran, as I see it, is that their cars are clearly not ADA compliant. It will probably have to be larger, which probably will mean larger guideway to support them and therefore higher costs (still cheaper and less visual impact than conventional monorail though).

The other problem I haven't seen addressed is the millions of passive mag coils which would be packed into the Skytran guideway-- how far out of alignment could one get without affecting the ride?.

No one who thinks a fleet of individually maintained computer-controlled cars driving on a chaotically-designed freeways is going to work has the right to call anything short of cold fusion a pipe-dream.

Packet-switched elevated ultra-light rail is a simple extrapolation from existing technology. Automagically self-driving cars, on the other hand, are seriously wacketoid.

CPRT is an organization dedicated to promoting these kinds of transportation systems, and Taxi2000 is one commercial system being developed. The washington.edu evaluate many different systems.

Note that it is essential for these kinds of systems that cabs are small--if they hold many people, they either need to stop a lot (=longer travel times), or they waste a lot of space and resources.

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!

Another good web site on the topic is Taxi2000.

Make sure you check out their FAQ.

The important topic that's always brought up is infrastructure. The beauty of the PRT design is that the infrastructure costs aren't all that appalling, since all the system needs to run is a narrow elevated track which can be built above existing roadways (so no right of way issues, etc). Yeah, it's more expensive than bus stations, but it's *way* cheaper than tunnels or elevated train track.

Another good web site on the topic is Taxi2000.

Make sure you check out their FAQ.

The important topic that's always brought up is infrastructure. The beauty of the PRT design is that the infrastructure costs aren't all that appalling, since all the system needs to run is a narrow elevated track which can be built above existing roadways (so no right of way issues, etc). Yeah, it's more expensive than bus stations, but it's *way* cheaper than tunnels or elevated train track.

This is a very smart idea, although it is not dissimilar to PRT (personal rapid transit), a sort of fringe and relatively unimplemented technology. As a public sector planner, I see three things to think about with this sort of 'personalized rail' approach:

(1) Capacity - These personal rail car concepts tend to fail when it comes to extremely dense corridors. As you can imagine, heavy rail can push many more people through a single rail corridor than this sort of technology. Right now you can push about 2K cars/lane/hour, compared to densities of nearly 10K for heavy rail systems. With this technology, you could decrease headways and maybe squeeze another few K through, but:

(2) Cost - these rail systems still cost on the order of $5M US/km to build, while each highway lane only costs about $200K to build. So, you are still getting less for your tax money with this stuff. Not that I am totally against this, though. Essen (Germany) has a clever system that does this, except the cars are busses that turn into light rail. I can see these applied intelligently for mid-range suburban corridors where other forms of transit are not applicable, but this brings us to the final issue:

(3) Consumer Adoption - when you are trying to get customers to change modes and you are asking them to make large capital outlays to do so, you are asking for trouble. This is the main issue with automated highways (like those prototyped at Berkeley). You can build the public infrastructure, but without private investment on a large scale, it does not fly.

For these reasons, I think that this might be a great transit technology, but will have a hard climb to become an accepted mode in urban areas. I guess that we will have to wait for the super-magical-mysterious panacea that is IT!

For that matter, we only have a half-dozen to dozen cities where local mass transict *can* be practical.

However, I don't think things are entirely lost. I really think Personal Rapid Transit could work in most US cities. The quick summary, is small cars (one to three people) running on elevated tracks (but very small tracks, since the vehicles are light), with automated navigation (which is really easy, unlike cars, because they are on tracks).

The great part is that it doesn't require any special technology. It uses wheels, electric motors, and tracks on stilts. Nothing very expensive. Only the automated navigation is slightly technologically difficult, but I think that is quite doable. Even running at 30 or 35mph, it's still far faster than other forms of public transportation when considering the total travel time (including waiting, transfering, and walking to your final destination). In Chicago, it would be faster than driving most of the time.

People are of the perception that public transit has to be high-volume to be efficient, but that's not really the case -- if you can move people in a more parallel fashion, it can be efficient on a smaller scale. In this case, you don't stop until you get to your destination, and the cars can run fairly close together.

Sadly, governments just keep putting money into light rail, which is a complete waste. I wish it wasn't so -- but it just doesn't work, it's too slow, too irregular, and doesn't get people where they want to go.

Anyway, for someone who is interested in PRT, there's information to be found at Taxi 2000 (well, that name doesn't make sense anymore, does it?) and Citizens for PRT.

Actually, sometimes "The Future" is a self-fulfilling prophecy. The architect (I forget his name) who popularized rounded and wedge shapes on buildings with assorted protuberances (I actually first became acquainted with the shapes as the background of The Flash's visits to the future) had a strong influence on today's architects. Materials, functional requirements, and expense affects actual designs but the influence is visible.

Flying cars were popular in the future of the 1950's. The founder of Moller has been striving toward it ever since, and test flight of the four-seater Skycar prototype is scheduled this year.

Transit methods such as the Disney monorail have also been around for a long time. Personal Rapid Transit devices have assorted designs, of which Taxi2000 is my favorite. 3-4 passenger vehicles which take you from your station directly to your destination station. No schedules, and a tiny overhead track. These PRT technologies have actually greatly gained capabilities with microcomputers, as now automated guidance and control is much simpler and cheaper.

And I recently read of a cellular wrist phone...

I'd prefer a PRT system like Taxi2000. Walk less than 4 blocks, push the button to call a vehicle, while waiting tap the touchscreen with my destination, get in the car. The vehicle goes automatically to the stop nearest my destination. The vehicles are for 3-4 riders and do not stop to pick up/drop off more riders.

Or maybe you'd prefer an automated taxi system. But it won't work on regular roads, although I like the small elevated tracks and 4-passenger vehicles being prepared for the Chicago suburb.