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Stephen Rees

The transfer penalty - and the perceived cost of uncertainty in making connections - are both real and must be measured. Yes many models use gross assumptions - but they can also be calibrated to local circumstances. And adding information systems, and other facilities at transfer points can reduce the perceived cost of transfers. But so many systems design networks - and transfer points - to minimize the operational cost not provide the best service to the passenger - and win new riders.

What is REALLY good for a city is when transfer points are made the centrepiece of good urban design - or "development oriented transit" as Sam Adams calls it. Talking about transportation as though it is a stand alone topic and not one intimately involved in the urban fabric is a good indicator that the writer has not taken the care to study the impact of decision making on how people live. Transport is a derived demand - and currently we demand far too much motorised transport because of our disdain for urbanity. Transit systems need to be seen as part of a much bigger picture of remaking our urban places.

Nathanael

But the complaint about transfers is not usually about *one* transfer, particularly a well-designed one.

The complaint is generally about *multiple* transfers. Taking two trains (or two buses, or one train and a bus) is not much worse than taking one. Taking three trains starts to get a little annoying, but if they're high-frequency and the transfers are easy, still not too bad. Taking four trains is pushing it, though still done if the transfers are good -- and taking four buses is just unpleasant. Taking five trains is quite unpopular.

This calls for well-designed transfers and an attempt to *limit* the number of transfers. To their credit, this is being done in modern designs by attempting to concentrate transfer points. Gaps such as "arrive in London at Paddington Station, leave from London Bridge, take two Tube lines to interconnect" are not attractive; super transfer centers like Berlin's Hauptbahnhof are.

The hostility to transfers comes from situations like London's, or Chicago's multiple commuter train stations (interconnect by... walking several blocks or getting a taxi. Or taking two buses.)

David Levinson

Well said, it is all a question of trade-offs of travel delay for schedule delay, and how thick the market is. If there is sufficient demand for frequent service, direct routes are better, but until there is such demand, frequent indirect service may be preferable to infrequent direct service. The worse is infrequent indirect service, which will attract almost no-one with an option.

Beige

It would help too if the transit vehicle is going a significantly faster average speed than a bicycle, which normal bus service does not. So for me the trip from home to city center, which I can do on one bus that runs more-or-less directly diagonally across town, is as fast by bus as by bicycle if we don't count the wait for 20-minute frequency service against it. From work to city center, similar. But home to work involves a trip south-east to city center, a long wait, then a transfer to a bus that goes back as far west as my starting point was. Can bicycle direct to work in a third the time, and a car is faster still.

Daniel M. Laenker

@Nathanael: What's more, can you imagine the five-train or 4train1bus trip it would take to get to LAX from a place like Fullerton or Sylmar? Los Angeles is admittedly trying to resolve one major piece of the problem by improving its downtown connections, but it's still hamstrung by numerous connectivity issues.

M1EK

This ignores the fact that transfers can also be missed (and often are). Consider how much more people will pay for a non-stop flight from A-B to avoid having to go through DFW and miss a connection, for instance. (The airlines have noticed!)

EngineerScotty

Of course, the penalties for missing a transfer on a mass-transit system, and missing a scheduled flight due to a delay, are quite a bit different. One is frequently measured in minutes, the other in hours.

M1EK

Likewise, I'd deal with a 30-minute delay on a missed flight when I fly every month or two on business. I would not tolerate a 30-minute delay due to a missed connection very often on a daily commute. Especially if I own a car that I can go back to.

Alon Levy

In the German-speaking world, transfers are timed, and trains stick to schedule, so you can be sure you won't miss the connection.

Elsewhere, urban rail systems don't always time transfers, but the waiting times are still short because of the high frequencies. For example, Singapore's central transfer station doesn't offer timed connections, but trains run every 6 minutes even off-peak, so missing the connecting train isn't a big deal.

Jarrett at HumanTransit.org

Thanks, Alon.  Yes, my example above was specifically about high-frequency transfers, and the fact that with a limited budget, you need to require the transfer to build the frequency.  Note that the travel time estimates in this post are average.  If you just miss a connection, the waiting time at the connection is 10 minutes instead of 5, still no slower than the low-frequency, direct-service option.

M1EK

It would be nice if the 'new transit' cities were talking about building rail networks with frequencies like the ones you and Alon are talking about.

They're not.

They're building commuter rail at 30-minute headways, or, at best, light rail at 15-20 minute headways. The transfers, if they exist, are to other light rail lines at 15-20 minute headways, or to awful city bus service.

Let's be real here - in THAT environment, you'd better make sure that first rail line delivers a direct ride for most riders or you might as well not even bother.

(And starting those systems as 'shorter, multiple, high-frequency' is not an option - I'm referring to cities like Dallas, Seattle, Austin, etc here - many are assuming lots of transfers AND high headways, in other words - like Austin's idiotic Red Line).

Alon Levy

M1EK: what you're saying is that those transit builders are incompetent, so they couldn't implement competent solutions well. In either case, the response should be to dump the local planners and replace them with people who know what they're doing.

When the system is run well, you can time transfers. When it's built well, the first line will be an urban rail spine extending in both directions from the CBD, maximizing ridership and minimizing operating costs; the suburban lines will come later.

It's not that hard. Calgary did it right, and got the busiest light rail system in North America out of it.

M1EK

No, Alon, I'm saying that the transit planners operate in the real world - where designing a high-frequency multi-line rail system is not politically or economically feasible.

The choice is either between a good light rail line that carries its own weight without requiring a bunch of transfers, or a bad rail line that forces everybody through one or more 'intermodal' centers, usually on to buses.

You can't time transfers on to / off of city buses. South Florida learned this the hard way.

Chris Karnes

Great post. What do you think about "timed" transfer centers? My city has had them since the County absorbed our city's transit authority thirty years ago. We, the riders, find them to be dead, desolate, uncomfortable and disconnected suburban areas where there is practically no transit service outside of the half-hour pulse. They cause excessive travel time, mainly because the transfer areas aren't central, they're mainly on the periphery.

Some effort, like you've said, should go into making transfer areas easy to navigate, but one additional point might also be to have such places where one can get some use out of "wait time" to run errands: to buy a few groceries, to get a cup of coffee, etc. in cases where one inevitably misses a connection.

Pierce Transit could use some of your expertise. They're in the middle of redesigning the system thanks to a change in leadership and constrained sales tax revenue. If you could take a look at the network, I'd be grateful for any thoughts you might have about it. Heck, maybe the board could even hire on as a consultant. You'll find more information at http://PierceTransit.org It's the second-largest public transit agency in Washington State.

M1EK

I forgot a long time ago to post this; please forgive me.

Austin's Red Line, which requires most potential passengers to transfer to a dedicated shuttlebus to get to their final destination in all of the major activity centers in the core, has seen ridership drop off a cliff since revenue service began:

http://mdahmus.monkeysystems.com/blog/archives/000652.html

Just today, the city's urban rail election (which actually would carry tens of thousands per day rather than the 400 the Red Line is now hauling) was pushed off to 2012 at the earliest because the Red Line has destroyed momentum for rail here:

http://mdahmus.monkeysystems.com/blog/archives/000653.html

So sometimes, in fact, transfers aren't good for you and your city; sometimes they're the death of future transit service, in fact.

Annonymous

One major assumption with Jarett's "connective" model is that it assumes that the transfer point is always on your way, that is, passing by it won't add any time beyond the overhead of the transfer itself.

In reality, this assumption is very often not true. Consider Jarett's own example (assuming his map is drawn to scale). A trip from residential area 1 to activity center 1, or activity center 1 to activity center 2 would require traveling a very circuitous route just to pass through the transfer center. The difference in travel time between the "direct" option would be far more than the wait for the second bus, especially if these are slow buses with frequent stops, operating in mixed traffic.

I've seen numerous examples of systems in which buses take excruciating detours so that all buses that serve an area meet at a single point. This makes travel extremely slow for anyone passing through the transfer point, regardless of whether or not they actually have to transfer. To make matter worse, the millions of dollars that get spent to construct the transit center in the first place reduce money available for operations, resulting in lower frequencies and an even worse experience.

Dexter Wong

I agree more with Jarrett on transferring. In my city, I can go to a major shopping center by either a direct line or by transferring. But I prefer to transfer because the direct line runs infrequently, while two other lines that run more frequently can get me to the center sooner than if I had to wait for the direct line.

Opbrid

Maybe our city is unique (Granada, Spain), but the system works pretty well by having all the buses go to the main street (closed to cars BTW), where you transfer to another bus if needed. To me, one bus transfer is fine. Two is best avoided! Madrid metro on the other hand is way cool. Probably only a 2 minute headway on most lines! I don't know why anyone would bother to drive in Madrid.

Eric

While I agree with Jarett here, on the advantages of connections, when done right, I'd like to play Devil's advocate here and state a couple of objections that I haven't seem fully addressed:

1) Jarett's model assumes that expected wait time is half the headway. This looks great on paper, but the ability for this to actually happen depends on every bus sticking precisely to it's posted schedule to actually achieve the desired headway. In practice, as we all know, buses tend to get bunched and when they get bunched, the average wait the customer experiences is often significantly larger than half the headway.

2) Jarett's model is also based on the assumption that minimizing expected travel time is the objective. However, it is also important to minimize the risk of encountering a lengthy delay. After all, if you have to be somewhere at a certain time, it's the worst-case travel time, not the average-case travel time that determines when you need to leave home.

In Jarett's own model, the worst-case travel time with the connective model (assuming wait time = full headway) is 40 minutes, rather than 30 minutes, worse than the direct-service model.

Furthermore, any time you wait for a bus, you assume a certain risk that something happened before the bus got to your stop causing a lengthy delay. If the wait happens twice, you have double the exposure to such risk. For example, if each bus has a 1% chance of arrive more than 30 minutes late, the connective approach gives you a 2% chance of a 30+ minute delay, rather than a 1% chance with the direct service approach.

I believe the perceived reliability issues go at the heart of the problem of why so many people are reluctant to embrace a connective approach - in order for a connective approach to work, you have to be really sure that all services involved can be trusted to arrive at their appointed time. If people don't place complete trust in their transit agency to provide reliable service, they will always favor the direct service approach because it minimizes risk.

David Stosser

One point missed above is that in the Direct Service Option, there is no allowance for travel between Residential 1, 2, 3 or between Activity Centres 1, 2, 3. If they had been included and the total were still at 30min frequencies, then in terms of Trip Length | Frequency | No. Routes that's 20min | 30min | 12routes = 35min average journies or 10+10min | 7½min | 3routes = 27½min average journies measuring from a random arrival time.

In Brisbane

I just wish they would use connections in Brisbane. Bit of a furore over new bus routes going in at the moment.

http://www.brisbanetimes.com.au/queensland/calls-for-bulimba-glider-rejected-20120201-1qtbt.html

dave

I used to work for a system that relied heavily on transfers. The system was configured around timed transfers at transit centers, precisely the type of network you called for.

The transfers were relatively easy to make, but the knock we got was just how slow it was. Making a timed transfer work, especially mid-route, added a significant time penalty into the route. Depending on the trip in quesiton, it also added off-direction travel.

In your simplified example above, you assume that the moving time of the trip was the same. We did not usually find that to be the case. A quick examination of your hypothetical map ahd the length of the lines shows this as plausible in your scenario as well. That could eat-up your five-minute saving pretty fast.

I agree with your basic premises:
Transfers are not the end of the world
In a resource constrained world, you have to make trafe-offs.
Every transfer is not the same and there are things you can do to make them less of a barrier.

However, in your list of ojbections, you miss the one we heard the most.

Max Schneider

However, I would design the "Connective Option" a little different, namely in such a way that each of the three lines connects with the other two lines in two separate transfer stations instead of one mega station that connects all of them together like in your example.

I would offset each line a little, just like the Czech have done in Prague (focus on the center of the system, you get three transfer stations instead of a single megalithic station that people will only hate): http://de.wikipedia.org/w/index.php?title=Datei:Prague_metro_plan_2008.svg&filetimestamp=20081121174523

If you weave the tracks at each transfer station in the right way you will also get the benefit of "same platform transfer to the other line" which is impossible if it is a single station serving all transfers.

Chris C

While I generally agree with the "transferring can be good for you idea", there is a flaw with the analysis you provided on your hypothetical example. You claimed that with 1/3 the routes, they can run every 10 minutes rather than every 30 minutes, ceteris paribus (the same number of buses, and presumably the same average speed). The problem is, the average route length in your hypothetical example with only three routes is longer than the average route length in the nine route scenario. So headways wouldn't be quite cut by 2/3 if the same number of buses are running the same averge speeds.

In Brisbane

Brisbane has route 369 which is a cross town bus service placed into operation about 6 months ago. It runs every 15 minutes for the better part of the day.

Unfortunately, patronage on this route seems terrible, listed here TransLink>Bus Review>369 http://translink.com.au/ despite good anchors at either end and intersection with multiple bus routes.

Rowland Hansen

This discussion absolves city planners of their responsibility. If the three activities are co-located in three dense urban residential areas only one frequent direct connection with one stop in the middle would suffice.

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