When Reliability Matters Above All Else

This post is about situations in which the most important thing for transportation is reliability, more so than average speed or convenience. It’s inspired by two observations, separated by a number of years: one is my own about flying into or out of Boston, the other is from a New York Times article from yesterday describing a working-class subway rider’s experience.

My observation is that over the years, I’ve used Logan Airport a number of times, sometimes choosing to connect via public transportation, which always involves a bus as the airport is not on the rail network, and other times via taxi or pickup. My choice was always influenced by idiosyncratic factors – for example, which Boston subway line my destination is on, or whether I was visiting someone with a car and free time. However, over the last eight years, a consistent trend is that I am much more likely to use the bus arriving at the airport to the city than departing. I know my own reasoning for this: the bus between South Station and the airport is less reliable than a cab, so when in a crunch, I would take a train to South Station (often from Providence) and then hail a taxi to the airport.

The New York Times article is about a work commute, leading with the following story:

Maribel Burgos barely has time to change into her uniform before she has to clock in at the McDonald’s in Lower Manhattan where she works, even though she gives herself 90 minutes to commute from her home in East Harlem.

It does not take 90 minutes to get between East Harlem and Lower Manhattan on the subway. The subway takes around half an hour between 125th Street and Bowling Green, and passengers getting on at one of the local stations farther south can expect only a few minutes longer to commute with a cross-platform change at Grand Central. Taking walking and waiting time into account, the worst case is around an hour – on average. But the subway is not particularly reliable, and people who work somewhere where being five minutes late is a firing offense have to take generous margins of error.

When is reliability the most important?

What examples can we think of in which being late even by a little bit is unacceptable? Let us list some, starting with the two motivating examples above:

  • Trips to the airport
  • Work trips for highly regimented shift work
  • Trips to school or to an external exam
  • Work trips for safety-critical work such as surgery
  • Trips to an intercity train station

In some of these cases, typically when the riders are of presumed higher social class, the system itself encourages flexibility by arranging matters so that a short delay is not catastrophic. At the airport, this involves recommendations for very early arrival, which seasoned travelers know how to ignore. At external exams, there are prior instructions of how to fill in test forms, de facto creating a margin of tolerance; schools generally do not do this and do mark down students who show up late. Doctors as far as I understand have shifts that do not begin immediately with a life-critical surgery.

But with that aside, we can come up with the following commonalities to these kinds of trips:

  • They are trips to a destination, not back home from it
  • They are trips to a fairly centralized and often relatively transit-oriented destination, such as a big workplace, with the exception of regimented shift work for retail (the original NY Times example), which pays so little nobody can afford to drive
  • They are disproportionately not peak trips, either because they are not work trips at all, or because they are work trips for work that is explicitly not 9-to-5 office work
  • They are disproportionately not CBD-bound trips

The first point means that it’s easy to miss this effect in mode choice, because people can definitely split choice between taxis and transit or between different transit modes, but usually not between cars and transit. The second means that driving is itself often unreliable, except for people who cannot afford to drive. The third means that these trips occur at a point in time in which frequency may not be very high, and the fourth means that these trips usually require transfers.

What does reliability mean?

Reliability overall means having low variance in door-to-door trip time. But for the purposes of this discussion, I want to stress again that trips to destinations that require unusual punctuality are likely to occur outside rush hour. Alas, “outside rush hour” does not mean low traffic, because midday and evening traffic in big cities is still quite bad – to take one New York example with shared lanes, the B35 steadily slows down in the first half of the day even after the morning peak is over and only speeds up to the 6 am timetable past 7 pm. Thus, there are twin problems: frequency, and traffic.

Traffic means the vagaries of surface traffic. Buses are generally inappropriate for travel that requires any measure of reliability, or else passengers have to use a large cushion. Everything about the mixed traffic bus is unreliable, from surface traffic to wait times, and bunching is endemic. Dedicated lanes improve things, but not by enough, and unreliable frequency remains a problem even on mostly segregated buses like the Silver Line to the airport in Boston.

Frequency is the harsher problem. The worker commuting from Harlem to Lower Manhattan is if anything lucky to have a straight-short one-seat ride on the 4 and 5 trains; most people who need to be on time or else are not traveling to city center and thus have to transfer. The value of an untimed transfer increases with frequency, and if every leg of the trip has routine 10-minute waits due to bunching or just low off-peak frequency guidelines, the trip gets intolerable, fast.

What’s the solution?

Bus redesigns are a big topic in the US right now, often pushed by Jarrett Walker; the latest news from Indianapolis is a resounding success, boasting 30% increase in ridership as a result of a redesign as well as other changes, including a rapid bus line. However, they only affect the issue of reliability on the margins, because they are not about reliability, but about making base frequency slightly better. New York is replete with buses and trains that run every 10-15 minutes all day, but with transfers, this is not enough. Remember that people who absolutely cannot be late need to assume they will just miss every vehicle on the trip, and maybe even wait a few minutes longer than the maximum advertised headway because of bunching.

Thus, improving reliability means a wider toolkit, including all of the following features:

  • No shared lanes in busy areas, ever – keep the mixed traffic to low-traffic extremities of the city, like Manhattan Beach.
  • Traffic signals should be designed to minimize bus travel time variance through conditional signal priority, focusing on speeding up buses that are running slow; in combination with the above point, the idea of giving a late bus with 40 passengers the same priority at an intersection as a single-occupant car should go the way of the dodo and divine rights of kings.
  • Off-peak frequency on buses and trains needs to be in the 5-8 minute range at worst.
  • Cross-platform transfers on the subway need to be timed at key transfer points, as Berlin manages routinely at Mehringdamm when it’s late and trains run every 10 minutes (not so much when they run every 5); in New York it should be a priority to deinterline and schedule a 4-way timed pulse at 53rd/7th.
  • Branch scheduling should be designed around regular gaps, rather than crowding guidelines – variation between 100% and 130% of seats occupied is less important to the worker who will be fired if late than variation between waiting 4 and waiting 8 minutes for a train.
  • Suburban transit should run on regular clockface schedules every 30, 20, or 15 minutes, with all transfers timed, including with fare-integrated commuter trains.

55 comments

  1. Gok (@Gok)

    One weird side-effect of must-be-on-time trips: If you leave 90 minutes for what could be a 30 minute trip, you’ve got no real incentive to take the fastest route. So in these cases, you’ll probably take a one seat journey over a two seat trip, even if the former is much slower. This is a nasty feedback loop, as reduced reliability ends up creating more crowding and less efficient transit resource use.

    Airlines encourage people to show up early with lounges and wifi. I wonder if blue collar jobs could be encouraged to allow flexible start times.

    • Henry Miller

      Flexible start times for blue collar jobs are often impossible. If you aren’t there to put the wipers on the car the whole line cannot move and so the guy putting tires on is stuck sitting doing nothing. The more efficient the assembly line the more people who need to be working at the same time to get things done. If you are doing “piece work” that means you do everything and there is enough slack that you can arrive late. However even then there is often a team of people working together to get the job done, one person missing and the whole team is down. Of course companies need to account for sick workers somehow so they have some extra workers, but they can’t let late people use that slack.

      One important thing to note from above is you not only can’t be late, there is no point in being early. The company put in a “lounge” with wifi to wait, but nobody is paid for using it (there is nothing productive to do there) so people would still try to not arrive early.

      Even in white collar work, if one critical person is late for the meeting everybody else just sits around doing nothing. However generally there is more flexibility to have something else to do before the meeting to fill time, so you can arrive way to early to avoid being late and still get things done.

      • Herbert

        Airport trips are also outliers as even the most frequent travelers don’t do them every weekday.

        There’s one exception of course: airport workers. Their trip mode share is sometimes radically different from pax

      • RossB

        Yeah, a nurse who shows up early really can’t do anything. If they show up late then it is a big problem. In contrast, software engineers can show up early and get right to work. The employer wants them there at some point (so they can meet with other engineers) but they have very flexible hours.

    • IAN! Mitchell

      Does the whole “being five minutes late is a firing offense” exist in other industrialized countries?

      • Alon Levy

        I don’t know, but judging by the habits of people in Germany, they act as if it is. Even social events here start much more punctually than in New York.

          • Herbert

            Germans are annoyingly punctual but historically strong unions mean “sorry, bus broke down” is usually accepted as an excuse at work

          • Alon Levy

            This is in the context of generally reliable public transportation. Wikipedia tells me “sorry, train broke down” is an acceptable excuse for being late to an exam here and in Japan; in the US it’s unthinkable, and I don’t think the US education system is any more controlling or less forgiving than the Japanese one.

        • RossB

          I agree with all of your suggestions. I think bus lanes are probably the most challenging issue. Funding for better frequency is essential, of course, but if you have bus bunching, it is pretty much useless.

          In general the big problem with bus lanes is how exceptions are made. These are all reasonable. You want the bus lane on a major street. But you can’t close it off — you need truck access if nothing else. So you take a lane, and ban all other uses of that lane. But folks want to turn right, so you allow that. Then a truck decides they will just make a quick delivery. Next thing you know, the lane is crowded. The more needed the bus lane, the more likely the violations and the more likely delays will occur even with legal use (e. g. someone making a right turn from a BAT lane).

          Whenever possible, cities should build two contraflow bus lanes. The beauty of contraflow lanes is that there are very few violators. All the signs say “Do Not Enter”, or “No Right Turn”. A cop can easily spot a violator (“Hey, that ain’t a bus”) and give them a ticket. There is no wiggle room (no “I was just stopping for a second”). More than anything, you have no legitimate drivers delaying traffic by trying to use the lane to take a right turn (and being delayed by pedestrians).

          There are drawbacks. One contraflow lane can quickly lead to backups, as each bus has to wait for the next one (no leap frogging). That is why in most cases, it makes sense to have two. It doesn’t make sense if there is single large corridor (e. g. Atlantic Avenue in Brooklyn/Queens) — you need a pair of streets. Traffic lights are often out of sync with contraflow lanes, although this problem is exaggerated. If you have a pair of adjacent (two way) streets, then you time the streets the same going one direction or the other. It doesn’t matter what vehicles are traveling there. If anything, it makes signal priority a little bit easier. You don’t need anything special on the bus, since any vehicle going that direction is a bus.

          It takes some political effort to get two bus lanes each direction, but unlike a lot of half-ass efforts, it seems worth it.

          • RossB

            That was supposed to be a general comment (not one for this thread).

          • RossB

            @Alon — Contraflow lanes take up less street space, since you don’t need a center bus stops (you just have curbside bus stops). They also don’t require special buses. They are cheaper (for both reasons).

            Center bus lanes make sense when you can’t do contraflow.

          • RossB

            @Herbert — Trams only make sense when you need the extra capacity. Other than that you have exactly the same issues (transit lanes are transit lanes) except there are several other negatives with trams. They typically cost more to build, are less flexible and thus less reliable. An accident in front of a tram line can render the line inoperable, whereas a bus just goes around the mess. Bus lines can easily be detoured around temporary construction, or a fire, but trams can’t. Trams make sense only when you need them — when you need that extra capacity.

          • Herbert

            Trams don’t just bring extra capacity but lower labor cost and ceteris paribus higher ridership. You also get to use electricity instead of diesel.

            And a Rasengleis (track embedded in lawn) is a very strong psychological deterrent to motorist incursion

          • RossB

            @Herbert — The lower labor costs come with the extra capacity. If you don’t need it, then you save nothing. In other words, if you run buses every five minutes and they aren’t crowded, then running a tram won’t save you anything. Secondly, buses can run on wire. I can go over every point, but it has been covered before: https://humantransit.org/2009/07/streetcars-an-inconvenient-truth.html

            @Alon — Yeah, you can run the buses that way, but you still need to take up space in the middle of the street, and depending on the configuration, can require more space. Just to be clear, this makes a lot of sense in areas that have big isolated corridors where a one-way street would be crazy. A good example is Madison Street in Seattle, where they will have center running buses. But this is relatively expensive (to add the bus stops). In contrast, adding contraflow lanes on a one-way street just requires some paint.

          • Alon Levy

            It is not expensive to add a small raised curb for boarding. If Americans do not know how to do this, they should send people to Stockholm and learn from its example.

            And quoting Jarrett’s 10-year-old post and not the reams of further criticism of bus vs. rail is kind of irresponsible. (E.g. Jarrett reported that in Berlin he waited for a streetcar and a bus came instead, concluding that Berlin does not think there’s a difference; in reality, when a bus arrives on a streetcar lane, it’s because there’s a service change, and you’d bet people do notice and complain to BVG about it.)

          • Herbert

            Buses bunch. Trams don’t. Berlin has loads and loads of bus lanes with huge bunching issues. Incidentally many of them former west Berlin tram lines…

          • RossB

            >> Buses bunch. Trams don’t.

            You’ve never been to Toronto.

            Look, the only reason I cite Walker is because he is a damn good (published) writer. He lays out the advantages and disadvantages of trams. I can do the same thing in a comment, but it will take a while (and the language will be a bit clunkier).

            Here is one way to look at it: Just imagine a streetcar with the exact same capacity of the bus. They both are electrified. They both have level boarding. They both have doors on both sides. They both have lots of doors, with off board-payment. What then, is the advantage of the streetcar? The only one I can think of is that it has a smoother ride.

            What is the advantage of a bus? It can avoid obstacles, both temporary (an accident) or long term (construction). Routing can be changed easily, as situations dictate. Buses can easily pass buses — allowing for a leapfrog system. Tram rail either creates a hazard for bicycles, or you have to spend a lot of extra space and money protecting bikers.

            There are exceptions, but most of the time, buses can can use existing infrastructure. That makes them cheaper. It also make them much cheaper to expand. (That goes back to routing flexibility).

            The only time it makes sense to have a tram is when you need the capacity, or have an existing rail line. The breakeven point for capacity is a judgement call. It gets down to how frequent is frequent enough. For a rider, a bus running every five minutes is better than a tram running every ten. But you get diminishing returns. It is still better for a bus to run every three minutes instead of six, but not that much better. Walker puts the break point at four minutes, which sounds about right to me. After than, the gain in frequency is minimal. At that point, the user doesn’t gain much by running extra buses, and you wish the bus simply had more capacity (i. e. was a tram).

            Now, you can cite examples of where this capacity is needed, and that is fine. But I can also cite examples of where the capacity isn’t needed, yet they are building streetcars (or have built streetcars already). The point is, if an agency just ignores the fundamental advantage of streetcars (extra capacity) and just assumes they are better, then the agency is likely to spend a lot of extra money on something that doesn’t benefit riders one bit.

          • Alon Levy

            Okay, you’re saying “just imagine” but there’s empirical evidence on this subject: there’s a 34-43% rail bias, independently of speed. Turns out the ride quality matters (and multiple people with chronic pain have noted this to me).

            The point about electrification is neither here nor there, for a fundamental reason: electric buses require overhead wires, too. Yes, BEBs exist, but you really don’t want to deploy them in areas with serious winters. And then there’s the fact that the same cause of better ride quality on streetcars – they’re on rails – also means that boarding can be much more level in practice.

            Doors, same thing. The vast majority of buses don’t have doors on both sides, so if you’re getting a bus with doors on both sides, you’re paying a premium on equipment. (And you shouldn’t get such buses anyway, the best industry practice in developed countries is side platforms anyway. That Americans like their freeway island platforms is neither here nor there.)

          • RossB

            >> It is not expensive to add a small raised curb for boarding.

            Yeah, but it is still cheaper to have curbside boarding. Riders also have to cross the street to get to the bus stop.

            Neither of those issues are huge. The biggest disadvantage is the loss of roadway space. It requires an extra lane for the bus stop, in addition to the bus lane.

          • Tonami Playman

            To add to the advantages of rail over. Lower long term maintenance on the track way compared to a bus because the axle loads of a bus are concentrated at the tire contact patches accelerating roadway damage, while rail axle loads are distributed by the rails before getting to the track bed.

          • threestationsquare

            I think in most situations drivers are more likely to block the lane of a vehicle that *can* go around than they are to block a tram track, so the flexibility of buses to avoid obstacles can turn into a negative. This is especially an issue given the incompetent/malignant law enforcement of many US cities; it seems like NYPD blocks bus and bike lanes themselves far more often than they enforce them, and I expect they’d be a lot less likely to park on tram tracks.

          • Herbert

            To see another argument in favor of rail over bus, look at the non Anglophone rich countries.

            What do they overwhelmingly build?

            And haven’t we established already that the Anglophone countries are doing multiple things wrong when it comes to transit?

            If you want to build an electric bus which is “indistinguishable from a tram” you’ll pay a heavy premium for a worse outcome

          • RossB

            The point about electrification is neither here nor there, for a fundamental reason: electric buses require overhead wires, too.

            It is a lot cheaper to add or move wire than it is to lay or move rail.

            The vast majority of buses don’t have doors on both sides, so if you’re getting a bus with doors on both sides, you’re paying a premium on equipment.

            Sure, but is it really cheaper to buy a streetcar (with doors on both sides) than it is a bus with doors on both sides? Furthermore, a bus with doors on both sides can run on a regular route, while a tram is limited to the tramway. This is another example of added flexibility.

            As mentioned before, center platforms use less of the street — instead of four lanes for a center running bus (two bus lanes and two bus stops), you have three (two bus lanes and a center bus stop shared by buses going both directions). With regular buses and island platforms, you can sometimes squeeze it into three lanes (by having the buses move back and forth) but that can lead to less than ideal bus stops.

            Speaking of flexibility, I forget to mention that running rail up hills is difficult. Thus you have situations (like in Seattle) where the streetcar route is nonsensical, but avoids a hill. (Side Note: I find it interesting how my relatively provincial home town has so many examples of transit done right, and wrong. We have (or had) a bus tunnel, a subway, commuter rail, a streetcar, trolley buses, BRT-by-name-only and soon, real BRT. Some of the subway stations make sense, some are horrible. Likewise with segments of the subway line, as well as bus routes. I’m sure I can find examples throughout the world to support my case, but you’ll excuse me if I grab some from my backyard.)

            [Contraflow is] Cheaper and less protected from turning traffic.

            Not always. It depends on whether there are mid-block destinations. If there aren’t any, and left turns are allowed, then contraflow has fewer issues with turning traffic. [Note: For the following I will assume that cars run on the right side of the road.]. With contraflow or center running, a bus has to deal with cars going the other direction, and turning left in front of them. With center running, a bus also has to deal with cars going the same direction, and turning left in front of them. Therefore, for the intersections, contraflow is actually better. The only issues that come up are those involving mid-block garage entrances. Since contraflow prohibits access from the curb side lane, the only access would involve cutting across. But depending on the situation, adding mid block traffic lights (or traffic cops) would result in less delay for a bus than having cars turning in front at every intersection.

            A good example of this dynamic is Third Avenue, in downtown Seattle. The Downtown Seattle Association just released a report for the area (https://cdn.downtownseattle.org/files/advocacy/dsa-third-avenue-vision-booklet.pdf). Third Avenue has a lot of buses (peaking out at 290 an hour), more than any street in the U. S. city (apparently), even if ridership along the corridor is not highest (although it is still pretty big). There will be fewer buses downtown as the subway expands (and they build the pieces they should have started with) but Third Avenue will still have a lot of buses (over 200 an hour). Right now the buses run on Third Avenue, a two way street. General traffic is largely prevented from accessing the street, but there are still exceptions (similar to what I mentioned at the start of this thread). Thus the large number of buses often get stuck as a delivery driver stops to drop something off, etc. The association wants to improve bus flow as well as make the street friendlier for pedestrians. There are several ideas listed in the document, starting on page 53. The one that would be ideal is contraflow on Third, along with contraflow on Second or Fourth (each of which are already one way streets). It is labeled “Transit Couplet” in the diagram. Unlike center running, the buses use two lane each direction, not three. Unlike a transit mall, general purpose cars and trucks still have access to each street (albeit one direction). Bus traffic (and traffic in general) is spread out between the streets (Third Avenue no longer has four lanes of buses) yet you would have better throughput than today. The only issue is whether there are lots of mid-block parking garage entrances, and as it turns out, there are none.

            Again, it isn’t a solution that works everywhere. But it is cheap, and has advantages that aren’t obvious. Buses (or trams) in BAT lanes are often delayed by cars acting legally or illegally. Contraflow lanes rarely have that problem.

          • RossB

            I think in most situations drivers are more likely to block the lane of a vehicle that *can* go around than they are to block a tram track, so the flexibility of buses to avoid obstacles can turn into a negative.

            You’ve never been to Toronto either 🙂

            Or Seattle for that matter. It’s tiny streetcar system is routinely blocked. As for New York, I wouldn’t bet on anyone being too concerned about blocking a streetcar. I’ve seen New Yorkers routinely block all lanes of traffic “just for a minute” while they deliver a package (or pick up a fare). Drivers honk, people curse, life goes on.

            And haven’t we established already that the Anglophone countries are doing multiple things wrong when it comes to transit?

            Right. And towards the top of that list are American cities that have built tram lines with tiny streetcars that carry fewer people than regular buses. It is like buying a Ferrari, putting cheap tires on it and never going over 100 KPH. It looks cool, but you have missed the whole point of the vehicle.

      • SB

        More so that most of US has fire-at-will laws.
        So that employees can’t be late or risk being fired.

        • Alon Levy

          I think in Japan, persistent tardiness is actually an official reason to fire a worker whereas generally low productivity isn’t? I’m not sure, though.

      • Lukas

        It would be very hard to
        fire somebody over this in Germany (if it is really not the fault of the employee because he/she used an adequate risk timeframe to avoid beeing late). I struggle to imagine any situation in which an actual blue collar worker could loose his job over this on a regular workday.
        Immediately it’s basically impossible, because firing an employee instantly is only possible in exceptional circumstances.
        But even for a “normal” procedure being late is not likely to be a legitimate reason to fire somebody, especially if it is the first time.

        • Henry Miller

          Generally you are not fired on the first time. However it goes on the record, if you are persistently late you can get fired for it.

    • Alon Levy

      That particular commute doesn’t really have this effect, though… Lower Manhattan is only served by the 4/5 trains, not the 6, so either the worker already has a one-seat ride on the express (if she lives near 125th Street) or she’s switching from the local to the express anyway (if she lives closer to 116th, 110th, or 103rd).

      Generally, if reliability is critical then people are less willing to make untimed transfers. Local/express transfers in New York are probably still an exception, especially now that within one dwell a passenger can go out, look at the arrival board, and make a decision whether to get back on the local; the general behavior I’ve seen of New Yorkers at such stations is that they transfer zero-penalty, i.e. they do not impute any transfer penalty and decide whether to switch based purely on actual end-to-end travel time.

  2. marcel

    Yes, making public transit free resulted in a 30% ridership increase. Don’t misrepresent it.

  3. Herbert

    You’re missing one issue… Because it’s an incredibly dumb issue and Nuremberg is the only city I know that has it…

    Walk distance within the “same station” for different modes. The Nuremberg S-Bahn has a bunch of interchanges to the subway (at Hauptbahnhof, Rothenburger Straße Fürth Hauptbahnhof, Fürth Klinikum and a few others) nowhere is the walk from S-Bahn to U-Bahn short. And on the interchanges from S-Bahn to tram (e.g. Steinbühl) the walk is excessive. This adds time to each transfer and makes both ways timed transfers impossible. That might not be an issue for some transfers, but off peak the tram drops to twenty minute headways and the subway never goes to the airport more often than once every ten minutes…

    • Alon Levy

      Yeah, so there’s no way you’re doing timed urban transfers with these stations. The places where timed urban transfers are feasible are cross-platform stations like Mehringdamm or Wittenbergplatz, or two levels of cross-platform transfers stacked one on top of the other like 53rd/7th in New York (where due to poor design from the 1930s the most useful transfers require descending one level and are not cross-platform). You can do Swiss-style timed suburban transfers, but that’s at suburban frequencies, not urban ones, which is why U- to S-Bahn timed transfers aren’t a thing anywhere I know of.

      That said, a 20-minute tram should be able to have timed transfers somewhere along the route…

      • Herbert

        It should, but if you look at an aerial shot of Steinbühl, there’s no way someone gets from the Tram 4 to the S-Bahn (or the other direction) during the dwell time of either. And as the S-Bahn is single track there, there’s no easy way to increase dwell time

      • adirondacker12800

        where due to poor design from the 1930s the most useful transfers require descending one level and are not cross-platform

        Or poor design of the original subway and BMT, not keeping out of the way of what you would want. That 50th and 8th has two levels and Fifth does too, hints that perhaps something more complicated is going on.

        • Alon Levy

          The problem isn’t that it’s two levels, the problem is that the useful transfers are UWS Queens and they’re not the ones that are cross-platform.

          • adirondacker12800

            Aww isn’t that too bad? Pesky three dimensions, gravity and how steep a hill trains can climb. The level crossings under 53rd and 8th and 53rd and 6th would hurt capacity? Or the whole extravaganza gets really deep? And those pesky pesky existing subways already there?
            I forgot about the quirkiness of 47th-50th too, southbound local is in the middle and the express is against the wall. Local, express, two destinations, what were they thinking? I don’t want to hazard any guesses about how much it has to do with making 6th or 8th or both six tracks someday.

  4. Patrick

    This intersects importantly with the discussion of capacity in previous post. A five minute delay on an under-capacity train might not impact travel time much more than the delay itself. However, when at capacity these delays create higher passenger densities that cascade into bunched trains. This further underscores the importance of both high frequency and even headways at the peak hour.

      • astromme

        Yes, in SF the MUNI trains do bunch. I see it on the N, KT, J, and maybe others. However, they are a special case because they act like busses outside of the market st. tunnel (surface-level, generally no dedicated right-of-way).

        • RossB

          Yeah, any time you lack right-of-way, you are likely to get bunching. Streetcars in Toronto bunch all the time. I’m sure other streetcars in North America do as well, unless they are so short and infrequent as to be tourist attractions, and not much more.

          While technically not bunching, delays based on headways are essentially the same thing. A train can’t enter a tunnel because another train is using the track. This happens all the time the New York Subway, and I’m guessing any system that is old, and hasn’t had the proper investment. I’m pretty sure this happens with the light rail in Boston as well, because of all the splitting.

  5. James S

    A great reason to improve bicycle facilities. For shorter trips, it is usually the most reliable in terms of time duration. With e-bikes, the range is expanded as well. If you take the east river greenway, for example, your bike commute time is +/- 1 minute every day.

    Also, in my experience, jobs where you have to clock in and out of, like McDonalds, give you a tolerance under 5 minutes. Usually its 60 seconds.

    Hence the line of people at the machine looking at the second hand on the clock to get ready to clock in.

    • Herbert

      Unfortunately some of those jobs require you to arrive in uniform, so for some people biking there is out of the question…

  6. RossB

    Add daycare to the list of trips that are extremely time sensitive. You can show up early, but if you show up late picking up your kid, you get charged a bunch.

  7. electricangel

    Getting to the airport in Boston via subway and bus is far riskier than the reverse, Alon. You chose wisely.

    I have missed planes because the shuttle bus from the blue Line first stops at the Rental Car Building. And sits. and sits. I’ve waited as long as 10 minutes there while precious seconds ticked away. It seems absurd in the face of it, but Boston chose to insert delay going TO the airport, rather than FROM it, in other words during the time people are rushing to make a scheduled departure.

    I tried the silver line to the city once, in my effort to reach South Station from Wonderland, transferring at airport T stop. I violated my own rule: if a train is available, take the train rather than the bus. The bus was late for its scheduled arrival; the bus got caught in traffic going into the tunnel; then the driver somehow turned a corner inappropriately, not only delaying his bus but every bus behind him, and ones leaving South Station as well. I have never since departed the blue line, preferring to get off at State and walk the 12 minutes to my track at South Station. If the timing is too close, I’ll gamble on a transfer to the Orange line and a trip to Back Bay… but that is usually a losing bet, as the average latency on the OL is 8-9 minutes, meaning I can expect to lose 4.5 minutes in waiting, eating up my savings from walking.

    I think there’s simply no place for buses in reliable transit in cities large enough to have dense traffic. I’d have thought that a reserved path, like the Silver Line in Boston to South Station would have been OK, but I saw that even reserved bus lanes depend on the driving skills of bus drivers. Most are very good, but it took only one to make my trip from Airport T to South Station 4x longer. This rarely happens with subways, and I bet never happens with driverless rail systems like Vancouver.

    • Herbert

      The driverless metro in Nuremberg has breakdowns. Very rare, but they do happen.

      • electricangel

        What causes the breakdowns? NYC gets a lot of delayed trains due to sick passengers. We also have conductors who are too slow to close doors, which then sets thousands of people into a late cycle.

        I visited Nberg back when the 4 streetcar went right to the Hauptmarket. The subway always seemed a little grim; I’ve only taken it once, to the airport. Great to see how much they’ve preserved of the Stassenbahn.

        • Herbert

          The Straßenbahn has half the length it did in the thirties. But they’re expanding it again to Erlangen… That extension should open by 2030 at the latest…

          I’m not 100% sure, but I think the breakdowns are usually caused by “if in doubt break” circuits which think of any obstacle as a potential person in the tracks. There’s also the issue of passengers blocking the doors (they close automatically unless something is detected by the light thing)

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