[HN Gopher] Bus Bunching
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       Bus Bunching
        
       Author : surprisetalk
       Score  : 40 points
       Date   : 2025-07-20 14:24 UTC (4 days ago)
        
 (HTM) web link (www.futilitycloset.com)
 (TXT) w3m dump (www.futilitycloset.com)
        
       | AndrewDucker wrote:
       | Digital bus timetables at the stop, so that you can see that your
       | bus is running late, or that the next bus is right behind it,
       | definitely make a difference here, because you can make a
       | sensible choice without the driver having to explain to everyone.
        
         | tialaramex wrote:
         | The displays are gradually less important because a growing
         | fraction of the population are already carrying a display with
         | wireless networking, on a personal device the UI can show you
         | your exact route and where the bus you need is now etc.
         | 
         | These could still be smarter, I remember a year or two ago
         | stood at a bus stop, watching the position indicator for a bus
         | I wanted to catch and realising as it in real life appeared at
         | the next junction - it was diverted away from my stop, one of
         | the icons I'd been ignoring was a deviations from normal route,
         | it's often set [road construction work] but _that week_ the
         | diversion avoided the stop I was stood at. That bus goes in
         | long loops so I caught it about a quarter mile away after a
         | breathless run, but a smarter app could say
         | 
         | "Hey, you seem to be waiting for the U6H, at the Broadway stop,
         | and it's not going to that stop. Walk this way for a few
         | minutes to reach a temporary stop at which today's U6H will
         | pick you up instead."
        
           | xandrius wrote:
           | Let's put even more things on a device which is extremely
           | addictive to many.
           | 
           | I love my local region e-ink screens which just show me the
           | info without wasting too much energy.
        
           | AndrewDucker wrote:
           | The displays aren't that important for me. But for visitors
           | to the city, who haven't installed the bus tracker app,
           | they're still very useful.
           | 
           | (Also, signal is terrible throughout lots of central
           | Edinburgh. I can be at a bus stop just off Princes Street and
           | get nothing at all.)
        
             | tialaramex wrote:
             | There shouldn't need to be separate apps. I like Edinburgh,
             | only been there twice and both times as a tourist but I
             | don't think "Wow, a separate Edinburgh bus app" would have
             | been a boon, whereas "Oh, my bus app just works here" would
             | make sense.
             | 
             | At one point Edinburgh's bus operator was part of the same
             | legal entity as the company which provided some bus
             | services in my city, though that is no longer true. London
             | has it right, no tourists and almost no locals care about
             | the bus companies. All the buses are painted the same
             | colour, all of them work the same way, who cares which
             | company operates the bus or why?
        
               | AndrewDucker wrote:
               | You _can_ get bus times from Google Maps. But almost
               | nobody seems to know that.
               | 
               | A standard "non-profit" bus app that all bus companies
               | could use would probably be very useful.
        
               | tialaramex wrote:
               | Isn't Google just giving you timetables?
               | 
               | That's not _useless_ but it 's no substitute for real
               | time information. Seeing "Your bus is six minutes away"
               | is reassuring in a way that "Well, the bus isn't
               | scheduled for another minute, and maybe it's running
               | late" is not.
               | 
               | In that "Oops, it's diverted" case which annoyed me, my
               | bus was, from that point of view, genuinely getting
               | closer, I could see it on the map. And then I realised,
               | with growing horror, that it's on a road which won't pass
               | me. Maybe that's a glitch? Then I saw the bus itself, in
               | the real world, too late it's actually not coming here.
        
               | themulticaster wrote:
               | There's both: GTFS is a standard for the regular
               | schedule, and GTFS-RT is a standard for realtime
               | information.
               | 
               | Link: https://gtfs.org/documentation/realtime/reference/
        
           | the_mitsuhiko wrote:
           | > The displays are gradually less important because a growing
           | fraction of the population are already carrying a display
           | with wireless networking, on a personal device the UI can
           | show you your exact route and where the bus you need is now
           | etc.
           | 
           | That is not my experience at all. I use busses every day and
           | I always use the posted times and don't want to look for it
           | on my phone. There are a handful of bus stops on my common
           | routes without displays and I always hate it.
           | 
           | I'm not sure there is a critical mass of people actually
           | looking at the apps for real-time departure information, at
           | least not in my city (Vienna Austria).
        
             | baq wrote:
             | Why not both? A QR code with a link to the same content as
             | it would've been shown on a display would work quite well
             | and provide redundancy in case of display hardware
             | malfunctions.
        
               | sho_hn wrote:
               | This is what the Berlin system does.
        
           | clickety_clack wrote:
           | I lived in a city with this once, and beyond the novelty
           | factor of the first few weeks after I found the app, I
           | stopped using it. Looking up routes on your daily commute is
           | just too much friction. The display at the station/stop is by
           | far the best indicator, you can see at a glance how long you
           | have to wait when you get to the stop.
        
         | derdi wrote:
         | Many subway systems have displays showing that the next train
         | is right behind the current one, and yet many people still
         | insist on getting on the current overcrowded one.
        
           | HappyPanacea wrote:
           | Perhaps they should offer a discount for boarding the next
           | train or a price increase for boarding the overcrowded one or
           | even both?
        
           | closewith wrote:
           | Which makes sense, as the next one may be equally or more
           | overcrowded. In a busy urban area, it may be hours before an
           | uncrowded train arrives.
        
             | derdi wrote:
             | I'd argue that that's not bunching, it's the entire system
             | being overloaded. A characteristic of bunching is that you
             | have a pair of vehicles which together carry an average
             | manageable load of passengers, but that load is unevenly
             | distributed between them.
        
           | DharmaPolice wrote:
           | Certainly with buses people have been burned where they are
           | told that another bus will be along in 2 minutes only for
           | that to evaporate and the next bus actually takes 15+
           | minutes. If that happens to you then you'll squeeze onto the
           | first bus you can physically fit.
           | 
           | It takes quite a long period of good service to undo one bad
           | interaction.
        
       | this15testingg wrote:
       | bus only lanes should be standard. One or two people in cars
       | shouldn't be able to delay an entire line, nor should they get
       | priority.
        
         | andreaja wrote:
         | Anecdotally, I'm pretty sure this phenomenon occurs even with
         | bus lanes.
        
           | AndrewDucker wrote:
           | It does. Because junctions still slow them down, as do groups
           | of 30 tourists all getting on at once, asking questions about
           | whether this bus goes to the castle.
        
             | sqrtc wrote:
             | You can tell exactly where you live based on the castle
             | reference. Happened to me once when a tourist in front
             | asked about the castle and I couldn't quite believe it was
             | real.
        
             | brainwad wrote:
             | > junctions still slow them down
             | 
             | This is also mostly fixable, with signal priority. Except
             | at complex intersections where different roads each have
             | transit lines fighting for priority.
        
         | xnx wrote:
         | > One or two people in cars shouldn't be able to delay an
         | entire line
         | 
         | It happens all the time that one or two people on the bus
         | itself (or, even worse, train) delay the whole line. The
         | fundamental problem is inflexible public transit.
        
       | anonymous_sorry wrote:
       | It isn't half annoying when you're on the London Underground or a
       | bus, and there's an announcement that you will be waiting for a
       | few minutes at a particular stop to "even out gaps in the
       | service".
       | 
       | It seems so perverse to artificially delay a load of passengers
       | because others are running late. But at a system level it
       | probably makes sense.
        
         | federiconafria wrote:
         | They could probably spread the wait and no one would notice...
        
         | juancroldan wrote:
         | If the lane is frequent enough, a 2-3 minutes delay is fine. In
         | many European cities the schedule is not specific times but
         | frequencies per time of the day.
         | 
         | Like "from 7AM to 11AM, one bus every 8 minutes". Then you have
         | the bus app if you want to optimize further (and if you're me,
         | miss it because of being too tight)
        
           | tapland wrote:
           | That's usually how they're scheduled though, and it's printed
           | that way to make the timetable shorter and much easier to
           | read.
        
           | anonymous_sorry wrote:
           | I meant when you're already on the vehicle mid-journey, and
           | you just have to sit at a random stop for a while so you
           | don't catch up to the one in front.
           | 
           | I get why, it just feels like your time is being wasted.
           | 
           | Of course, the trade-off is that next time you'll have a
           | shorter wait to catch a bus or train because some other
           | passengers had to sit and twiddle their thumbs for a bit
        
         | DharmaPolice wrote:
         | I get on many buses and 90% of the time the message is played
         | about "Evening out the service" it's because the drivers shift
         | is about to end and he/she doesn't want to wait at the driver
         | changeover stop too long.
        
       | lexlambda wrote:
       | Some of the proposed solutions are problematic. A public
       | transport systems absolutely needs to be reliable for the people
       | who use it.
       | 
       | Skipping stops is the worst in that regard and breaks the whole
       | point. No schedule causes issues downstream, since now there
       | won't be a schedule to depend on when needing to switch to trains
       | or other busses.
       | 
       | But in general, the only thing to realistically improve without
       | decreasing reliability is the amount of time spent at a stop
       | (also mentioned in the article).
       | 
       | All in all, I see these suggestions as "what to do in a worst-
       | case scenario", i.e. if the service already has major issues.
        
         | snackbroken wrote:
         | No-schedule works fine if (and only if) service is sufficiently
         | frequent, say every 5 minutes. The overwhelming majority of
         | intra-city trips will have 3 transfers or less in a well
         | designed bus network and when planning to catch a less frequent
         | service, it's acceptable to bake in a 15 minute safety margin.
        
         | baq wrote:
         | > Skipping stops is the worst
         | 
         | Depends. If the timetable is packed or the buses are already
         | bunched, skipping a stop is actually preferable - unless you
         | want to hop off at that stop, too bad then! ;)
        
       | cjs_ac wrote:
       | Discussion on Wikipedia:
       | https://en.wikipedia.org/wiki/Bus_bunching
       | 
       | Discussion of how to solve it in OpenTTD:
       | https://www.openttd.org/news/2024/02/10/unbunching
        
       | sebstefan wrote:
       | >Planners can set minimum and maximum amounts of time to be spent
       | at each stop, and buses might even be told to skip certain stops
       | during crowded runs
       | 
       | >Passengers might be encouraged to wait for a following bus, with
       | the inducement that it's less crowded.
       | 
       | >Northern Arizona University improved its service by abandoning
       | the idea of a schedule altogether and delaying buses at certain
       | stops in order to maintain even spacing.
       | 
       | FYI the real solution is bus lanes so busses don't get stuck in
       | traffic. But for that, you need to make space that isn't for
       | cars. So you won't get it in Arizona.
        
         | juancroldan wrote:
         | In Spain most city roads with 2+ lanes per direction have a
         | dedicated bus lane, yet you still get bus bunching and spacing
         | adjustments anyways.
         | 
         | - Imagine bus A is followed by bus B, it's 5PM and people are
         | leaving work simultaneously
         | 
         | - Bus A spends a lot of time on each stop picking passengers up
         | 
         | - When bus B arrives, fewer people are waiting and it tends to
         | take less time
         | 
         | - Eventually, bus B catches up to bus A so A must skip stops to
         | maintain proper spacing
         | 
         | As for why this doesn't annoy people: if both buses are already
         | close together, any ETA changes from spacing adjustments are
         | minimal, and bus A will show no destination on the front
         | display, so no false expectations are created.
        
           | kevindamm wrote:
           | except that bus A must often go to stops that it would skip,
           | if any of the passengers want to get off there.
        
           | sebstefan wrote:
           | If there's bus lanes the bunching happens much more slowly.
           | You fix it by giving slightly more time than needed to the
           | busses for their routes on the schedule, say, 20 seconds per
           | stop. That way if they lost some time on some stops, they
           | fetch it back later. With the inconvenience that all the
           | routes take longer
        
         | derdi wrote:
         | Bunching also happens on things like subway lines that have no
         | other traffic. Many passengers are irrational about forcing
         | their way onto already overcrowded trains.
        
           | actionfromafar wrote:
           | It's a coordination problem - taken in isolation, it's not
           | irrational. If _only_ you refrain from doing it, and 37 other
           | people do, you will still have to wait for the next train,
           | and the train in front of you will be almost as late anyways.
        
             | derdi wrote:
             | The wait for the next train is one factor, the overcrowding
             | is another one. I'm usually not in such a hurry that a
             | minute's wait would make a difference. But the next train
             | is very likely to be much less crowded and much more
             | comfortable to ride on. From my point of view the decision
             | is clear, in isolation, just from my own selfish point of
             | view. And I think many others are making a choice that
             | makes them unhappy. (Train systems differ, the one where I
             | live has sufficient capacity that you rarely get two
             | overcrowded ones back to back. I know there are places
             | where this does not apply.)
        
           | summa_tech wrote:
           | It's not as irrational as all that.
           | 
           | Subway system here has an amazing propensity to send random
           | trains on express tracks, especially during peak traffic. I
           | understand that this is done to alleviate congestion, but the
           | net effect is that when you see a train going somewhere you
           | want, you _seize the opportunity_.
        
         | closewith wrote:
         | Bus lanes exasperate this problem by fast tracking buses to
         | common choke points. It's one of the very few disadvantages of
         | bus lanes.
        
           | Zambyte wrote:
           | What causes the choke points?
        
       | dmd wrote:
       | I described this 25 years ago on _blush_ everything2.
       | 
       | https://everything2.com/?node=rutgers+bus+system
        
       | nix0n wrote:
       | In the Boston area, the bus drivers seem particularly likely to
       | react to this by the second bus passing the first (even by
       | crossing a double yellow: traffic laws are generally optional
       | here).
       | 
       | In the article this is presented as a symptom of how bad the
       | bunching is, but as a rider it feels like this helps the problem:
       | new riders are now getting on the bus that's less full.
        
       | Lvl999Noob wrote:
       | 1. Frequent service (<5 minutes between buses, ideally) 2. Enough
       | capacity to support rush hours (so each bus can straight up
       | refuse to take extra passengers) 3. Education campaigns and
       | police / fines / other external factor for the short term (to
       | break existing habits) 4. Separate public transport lanes so
       | buses don't get stuck in traffic or behind red lights.
       | 
       | IMO, these are sufficient for a good public transport system.
       | Skipping stops is the worst since it makes the whole network
       | unreliable.
       | 
       | If the above points are too high of an investment and skipping
       | stops is the only viable solution then a proper digital interface
       | is needed. If the schedule is dynamic then the information about
       | it also needs to be dynamic. I need to be able to know that the
       | bus I am on is going to skip my stop and plan my next steps while
       | I am sitting in the bus itself.
        
       | dang wrote:
       | Related. Others?
       | 
       |  _Why Do Buses Bunch?_ -
       | https://news.ycombinator.com/item?id=19558482 - April 2019 (150
       | comments)
       | 
       |  _Pittsburgh Bus Bunching (2016)_ -
       | https://news.ycombinator.com/item?id=17589349 - July 2018 (60
       | comments)
       | 
       |  _Why do buses bunch?_ -
       | https://news.ycombinator.com/item?id=9577476 - May 2015 (154
       | comments)
        
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