Economic comparisons between different automatic public transport systems

1. System Definitions

APTA (American Public Transport Association) has a page of Public Transport Definitions. There are other websites with definitions to be found. We at SwedeTrack Systems will clarify some of the terms used. Generally, these system concepts do not differ between supported or suspended cabins. But supported systems clearly dominate the market. AGT ("Automatic Group Transit" or, more correctly, probably, "Automated Guideway Transit") are systems which have many of the basic characteristics of PRT, but use larger, shared vehicles. They are intended for less expensive deployment than PRT-systems, and may use on-line or off-line stations. As a rule, the vehicles run after a time table. These systems are also called GRT (Group Rapid Transit).

APM (Automated People Mover) is a more general term for driver-less, computer-controlled vehicles. As of this writing, (June 2004) there are more than 100 APMs in operation throughout the world. In addition to this listing, there are about 20 driver-less Metro-systems both running and under construction. They are thus very often not single vehicles but complete trains, running on regular railway tracks.

PRT (Personal Rapid Transit) is a system which predominantly uses automated vehicles, no larger than small automobiles, to carry people and goods non-stop between stations in a network of comparatively slim guideways. The vehicles can be made available on demand, and are occupied by a single individual or a small group travelling together. PRT systems have off-line stations. SLT (Shuttle Loop Transit) is the simplest automated transit technology. SLT systems use even larger vehicles which operate on limited guideway networks with little or no switching capability. SIPEM in Dortmund is an example. We have not included SLT in this comparison.

2. Cost Components

Figure 1:1

One can see from the diagram in figure 1:1 above how costs for components contribute to the system costs on a percentage basis. We have compared Raytheon´s PRT, comparable AGT and a weighted evaluations of 17 existing AGT systems.

In Raytheon´s system, costs for guideways and project management dominate more than in other systems. When it comes to vehicles, one must remember that the smaller PRT vehicles cannot take as many passengers as the larger ones.

It thus takes more PRT vehicles to transport a certain number of passengers. Generally, since these are percentage comparison, one also needs to know actual cost estimates to make fair comparisons.

3. Cost Comparisons

A good economic comparison between different automatically controlled traffic systems is necessary if one wants to have a useful debate. Unfortunately, anything like a pure PRT system does not exist anywhere in the world as of this writing. But; there are more than 100 AGTs (Automated Guided Systems) in operation today, and from these systems there are some statistics available.

Trams (nowadays often known as LRT, which is short for "Light Rail Transit"), subways and bus companies also provide statistical information. The numbers quoted in this page are based on weighted evaluations and transfer of costs which we at SwedeTrack System believe to be typical of European (and maybe North American) conditions today. Some important assumptions:

Interest rate: 5% Time for writing off vehicles: 18 years for a bus 25 years for all other vehicles. Price of welded and treated steel - in the form it is used in a bridge: US$ 3 /kg. Much information has been obtained from the Swedish consulting firm of Transek and from other official information sources. All vehicles for public transport use have their individual nisches. Figure 2:3 below shows superficially how the costs for these are affected for varying traffic loads. We have compared these with the corresponding curve for an imaginary FlyWay-system.

Figure 2:3

As can be seen from the diagram in figur 2:3 FlyWay comes in between wath is commonly known as PRT and today´s automatic group transport systems (AGT) as regards cost. You could say that FlyWay costs about 15 - 20 % more than PRT, but FlyWay provides on the other hand a possibility to transport just as much people in a given time as a regular subway system. And, to booth, FlyWay can also handle containers and road vehicles.

Figure 2:3 does not take due consideration to the increased traffic revenues that such goods transportation would generate. Nor does the figure take into consideration environmental gains and time savings for passengers and goods transporters alike. FlyWay cannot compete with buses in the really low capacity field.

But if one also take into consideration the value of saving time, FlyWay´s competitive edge would be considerably increased. As can be seen from the diagram in figure 2:4, the buses will then appear to be more expensive, since their average speed is quite low and the traveltime correspondingly longer for the passsengers. Of course, this does not apply to inter-city buses travelling on the highways, only to urban street buses.

Figure 2:4

It might be of interest to see how the costs for a typical automatically controlled transport system (in this case an AGT system) divides as percentages of total system costs.

Figure 2:4 below shows median values from many different systems, based on information from Supine Yoder. You can compare this with figure 1:1.

Figure 2:5

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