Dual Mode Debate

Dual Mode Debate: Where's the public transit?

In which the author cuts to the chase, and then offers an olive branch

July 30-31, 2002. I'll pass on the urge to debate point-by-point with Francis Reynolds, because his position is perfectly defensible as well as being internally logical. See, facts don’t bother me, where I differ is how facts are translated into policy outcomes. Perhaps we can chalk up this ongoing debate to the likelihood that Dual Mode and Personal Rapid Transit are apples & oranges strategies for dealing with congestion. Both visions work, the answer to the question of which is best is a matter of personal preference.

However, Mr. Reynolds's vision of a dual mode world misses an important component-- what happened to the public transit? There doesn't seem to be much room for it in his Dual Mode equation. For Mr. Reynolds, the standard of service must be door-to-door, rather than convenient walking-distance-- yet the guideway system must be skeletal, with stations miles apart. This means the user MUST drive to and from the system. Shut out of Dual Mode are senior citizens, children traveling alone, and others who don't drive, can't drive, or on occasion choose not to drive.

What's the alternative for this demographic? Some Dual Mode designers speak of medium or large shared-ride vehicles (buses, mini-buses, GRTs, etc.) which can use the guideway some or all of the time. My general objections to these vehicles as a class are already noted in my original Dual Mode essay: even though they may use the guideway, they would retain some of the usual set of disincentives of conventional transit. Thus far, attempts to design these disincentives out of such vehicles are in my view not wholly successful, and in some cases creates new ones. For example, Palle Jensen's system is creating a "Maxi-RUF", a medium-size transit vehicle with compartmentalized seating. While riders would gain privacy, its other features do not represent, again in my view, a significantly better set of service characteristics than conventional transports.

In its "APM" mode (Source, #2 bullet 3 ) the Maxi runs between stations, which means it would have to stop at all of them, or at least at all of the ones that riders have specified as their destinations. Can service be on-demand? If they run frequently enough-- but to operate efficiently (i.e., not mostly empty) they would have to wait until a group of passengers gathers. Would the station interval be such to place all Os and Ds within walking distance? Not under RUF's design vision, in which the network is designed to suit the private RUF automobile, implying wide station spacing (above Source, #2 bullet 2).

In full Dual Mode, the Maxi would run on the guideway AND act as a collector-distributor, providing riders with actual door-to-door service in response to some sort of ride-ordering system, such as dial-a-ride. But this service would not be fully on-demand and not at all nonstop, because each rider would have to wait while the Maxi picks up and drops off other passengers. This could be difficult to coordinate. Presumably the Maxi would come to an interchange, leave the guideway, collect & distribute riders, reenter the guideway, come to the next interchange, leave the guideway again, collect & distribute riders, reenter the guideway, etc. All while the ride-ordering system is continually receiving requests. This wouldn't be attractive to people traveling a long way-- unless some Maxi service offers limited-stops, but this could be even more difficult to coordinate. And the Maxi would still get stuck in surface congestion when not on the guideway, just as would RUF cars.

Is dial-a-ride-- by landline/home phone, cell phone, or computer-- more convenient for transit users? I say it's no more convenient. On the one hand, it allows you to call the Maxi when you want it. But on the other hand that could be seen as requiring more effort than just walking to the bus stop and waiting. It also assumes the rider has a cell phone, or is someplace where access to a computer or landline is convenient.

Fare structure. Another layer of complexity is added by the idea that system operators could enhance the attractiveness of the Maxi with amenities, which would also enhance the system's revenue. This is a proposal of which I have only recently become aware, but apparently the idea is that some compartments on the Maxi would have luxury features (TV? Stereo? Leather upholstery? Internet?) which will allow a higher fare to be charged for using that compartment. Interesting, but in terms of the transit user's experience this means that dial-up Maxi service is on-demand only if there is a seat available in your price range, if not you have to wait for another Maxi. Sounds like an airline, not public transit.

Disclaimer: I am writing from an admittedly American perspective, I allow the possibility that RUF may seem obviously superior to a European. My only European experience is with Bologna and Firenze, which have central cities that are compact and dense, and I can see how Maxi-RUF could function in those environments. Of course, so do conventional mini-buses and the system of time-stamping biglietti purchased at Tabacchi, so I guess that's one of the comparisons that have to be considered. Due to my limited Continental experience I'll leave that comparison to others. Of course, I wouldn't say No if I were to be offered an extended all-expenses-paid fact-finding tour, for two, of European transit systems and developmental projects.

Dual Mode doesn't go far enough. Dual Mode supporters recoil from the number of stations required by PRT, saying that the same general level of service can be provided by a less elaborate network and fewer stations further apart. But this requires someone driving at each end of the journey, whether that be the individual or a bus driver. Would PRT be more expensive? Well of course it would. But PRT's increased coverage means more users, more revenue, and therefore affordability. Would the public accept an extensive PRT network? I am convinced that a public that accepts a viewscape littered with overhead power lines and cell phone towers will accept attractive slim guideways and small PRT stations-- once they understand the benefits.

More stations, closer together gets you more coverage and, if properly implemented, puts virtually all origins and destinations within walking distance. Naturally, this doesn't serve all trip types, PRT still accepts a role for the automobile. But Dual Mode, by merely automating private cars and buses, does not serve (or does not significantly improve service for) all types of transportation consumers.

In my admittedly personal agenda, providing an improved public mass transit system is equally as important as relieving traffic congestion. Dual Mode and PRT supporters generally agree that the way to accomplish the latter is elevated, automated guideways. It appears to me that PRT is better with respect to the former. Perhaps having to put up with a measure of inconvenience is the price of using public transit-- but my point is that that way of thinking is status quo, and that PRT represents a significant improvement in the quality of public transit as experienced by the average user.

In closing, may I note a possible win-win resolution to this debate: ULTra. It's being introduced as public transit PRT, but I think we all know that Martin Lowson's intention is to eventually open future ULTra networks to Dual Mode cars. Note that by the time that happens ULTra networks will already exist, designed-for-PRT, with all that implies: each system an assemblage of guideway loops, serving many stations spaced at about a half-mile. From a developmental standpoint, ULTra is in the lead. The precedent it is setting-- PRT first, Dual Mode later-- may be an example of which all of us, PRT supporter and Dual Mode supporter alike, should take note.

Last modified: July 31, 2002