SkyTran - The Future Of Travel

[afransen]

It's already been in operation (but not open for public use). In other words, it works. It is far from an optimal design, but it has the ability to demonstrate some of the potential of a real PRT system.

 

[afransen]

A Popular Science cartoon ca. 1955 updated for our current era. Huge amounts of ugly infrastructure for no particular purpose. The illustrations all show unidirectional lines, by the way, which relegates this to a Detroit - or Miami - style "people mover", the chief purpose of which was to fill the pockets of a given corporation for a given period of time.

Referring to PRT or the gondola thing? Well, there is nothing that precludes having bidirectional lines. The main reason to use unidirectional lines would be to lower the infrastructure cost for low-volume areas (for serving more residential areas, say). This is no different than one-way streets, which work just fine.

 

[SlickFranky]

It's already been in operation (but not open for public use). In other words, it works. It is far from an optimal design, but it has the ability to demonstrate some of the potential of a real PRT system.

It's a parking shuttle.

 

[afransen]

Nonetheless, it is essentially a PRT system. It would be a nightmare if deployed in an urban area, but a more elegant system could operate using the same principles fairly effectively.

 

[SlickFranky]

Yes, it's a (soon-to-be) functioning example of PRT. But it's a parking shuttle. $60M dollars for a job that a pair of mini-vans could have done, or a few valets with golf carts.

It will never work as a city-wide network, because whole system scales exactly the way roads & cars do, and we've already proven that model doesn't work. PRT is just futuristic cars on rails.

 

[afransen]

Well, it does scale better than cars. You don't need anything near the number of vehicles per passenger served, or parking. Also, vehicle capacity density is much higher. If a PRT lane operates at the same headways as cars on roads do (1.5 - 2 s headways--being conservative, it could achieve better), then one lane could have about the same capacity as two lanes of car traffic due to non-stop travel, while not requiring the same lane width.

When speaking of cost, it is worth noting that ULTra is a pilot, and not indicative of what a scaled system would cost. Also, its guideway is hardly designed to be cost effective.

 

[Darwinkgo]

So basically you're saying it has all the benefits of automated cars, with extra costs! I am not sure, but why don't we say... automate cars.

 

[DavidH]

So basically you're saying it has all the benefits of automated cars, with extra costs! I am not sure, but why don't we say... automate cars.

What happens when an automated car blows a tire? Has an engine malfunction? Has a tire from a truck start bouncing towards it on the road?

We're not yet at the point where we can automate a car and have it detect and deal with all of the edge cases where things go wrong. PRT, even with its limitations, is a more controlled environment, and has the advantage of centralized maintenance of vehicles.

 

[SlickFranky]

How much do you think maintaining 100,000 PRT vehicles will cost? I bet it's a lot.

 

[afransen]

I wouldn't expect a PRT vehicle to cost more than a car to maintain, especially considering it wouldn't carry a combustion engine and would likely have a mostly solid-state drivetrain. More importantly, one PRT vehicle could do the work of 5+ cars.

I just don't see us ever trusting computer guided vehicles at street level in urban areas. They have to be on a grade-separated right of way. And lo-and-behold, what do you end up with? PRT (although PRT wouldn't have private vehicles).

 

[Niagra & Adelade]

the only real argument in favor of PRT that has been put forward is that subways and LRT are too expensive, but PRT can be installed more economically. the only problem with that is that PRT can never be upgraded. PRT can only be installed in an area where no future increase in traffic could ever happen. and how many of those areas need anything more than decent bus service?

this is a solution in search of a problem.

or a pet project by people who don't like traveling on conventional transit systems.

why re-invent the wheel?

 

[afransen]

I don't think you understand PRT. PRT can be upgraded by added more guideways on a street (though one will carry a lot of traffic already), or putting less distance between guideways (a smaller grid). Of course, if there are areas where the traffic is just too high for PRT to handle it, we can use subway or other heavy rail. After all, high-use applications are where these technologies make sense. Desolate suburban thoroughfares? Not so much.