6 ms·

There's another thing that happens with busses that makes it worse. The further behind the previous bus a bus is, the more people will arrive at the bus stop.

There's another thing that happens with busses that makes it worse. The further behind the previous bus a bus is, the more people will arrive at the bus stop. The more people there are at the stop, the longer the bus has to spend picking them all up and selling them tickets etc. Therefore the delayed bus will tend to experience more delay. The bus behind them will have less people to pick up, so it will spend a shorter time at stops and tend to catch up with the first bus, so the two busses are dragged towards each other.

jjbinx007 2y ago
Also buses are more likely to let other buses out in traffic so that's another reason why you get clumps of buses arriving rather than regularly spaced ones
- ajuc 2y ago
  It's a law here in Poland that everybody has to let the buses leaving a bus stop to enter the lane before them. I think most people complaining about buses in this thread just live in a city where public transport isn't a priority so it barely works :/ The city buses I've seen in USA have 1 or 2 doors. It's already wrong - it makes the boarding time unnecessarily long. Then there's the tickets - drivers shouldn't be selling or checking the tickets. You should buy tickets in a ticket machine or on your smartphone. And they shouldn't be checked every time - it takes too long. Have a group of people who board random buses and check the tickets there while the bus is driving so as not to waste anybody's time. Bus schedules and routes should be designed with randomness in mind. There should be a small buffer (1 minute is enough if boarding is quick) to zero the randomness on each bus stop. Most bus stops should be mandatory so that 3 consecutive bus stops without passangers don't wreck the whole schedule (and then it spreads to other buses because you have to wait for 5 minutes at a bus stop for your departure time and you block entrance for other buses' passangers which makes boarding longer). If you just put an intercity bus (that can work with 1 door and driver selling the tickets) and use it as a city bus that stops every 1-5 minutes - it won't work. City buses should be optimized for latency not throughput.
Ylpertnodi 2y ago
>the longer the bus has to spend picking them all up and selling them tickets etc. In my country, apart from an app/ online, you can buy a ticket pretty much anywhere. I guess someone worked out that bus drivers with money are a potential theft risk, and also that selling tickets on the bus takes time and makes busses late(r than they would be).
- matrix2003 2y ago
  As a rider, I also just find it more convenient to buy tickets in an app. I can link my payment method, and purchase tickets in seconds whenever I’m ready.
- bluGill 2y ago
  If you rarely ride though cash is easier. I won't use the app again so I don't want it. Fortunately in the us multiples of $1 are good price points so exact change put it in the safe works well.
- jerlam 2y ago
  The slickest process I've seen is to just swipe your credit card, without any setup whatsoever.
  - jmm5 2y ago
    tap
  - SoftTalker 2y ago
    Often the most expensive though. You're paying the highest individual fare rate, possibly plus card processing fees. If you buy a transit pass or use their app you can get significant discounts.
    - grkvlt 2y ago
      in big cities in the uk (edinburgh, london, etc.) paying with a contactless tap of a debit card each journey will never result in paying more than the cheapest daily, weekly etc. travel pass. single tickets are gbp 2.00 and a daaily pass is gbp 5.00 so individual journeys are recorded and counted (when paid for with the same card, obviously) and at the end of the day, if more than three journeys have been made the total charge for the day is capped at gbp 5.00 - and the weekly total is also capped at the value of a weekly pass, etc.
mitthrowaway2 2y ago
That bus with more riders on board also has a higher probability of needing to stop to let people off at each location as well, slowing it down even further!
- ajuc 2y ago
  This is part of a good route design - most bus stops should be "mandatory" - which means the bus stops there no matter what. Some bus stops are "optional" - driver only stops there if there's somebody waiting or if somebody in the bus presses the "STOP" button near the doors. It's marked on the timetable which bus stop is optional. It's not worth it to make every stop optional because then the routes become too unpredictable and scheduling is hard. Usually there's like 5-10% of optional bus stops on each route - only in the places where very few people get in/out.
  - leereeves 2y ago
    OTOH, it's extremely annoying to sit on a stopped bus when no one is boarding or leaving. That discourages use of mass transit.
    - ajuc 2y ago
      It takes like 10 seconds. And you have to keep the schedule anyway - if you skip this bus stop you'll be waiting at the next one longer.
  - mitthrowaway2 2y ago
    For express or intercity busses, that makes sense, but for high-frequency regular bus routes, I can't imagine that working. It means thar bus stops would have to be extremely sparse, or else the bus trips would need to be extremely slow.
    - ajuc 2y ago
      Exactly the opposite. It sucks for intercity buses, cause there's no point. Bus stops are rare and buses don't "bunch up". It's essential for city buses. This is how it works in every big city in Poland, it's working great. More cities started to use this system over time, because it improves the scheduling so much. The point of city buses is that they drive in traffic anyway - they rarely drive over 50 km/h and they stop every 5 minutes. How regular they are is MUCH more important than how fast they drive. If you skip 3 stops because nobody waited there - you get to the 4th bus stop 5 minutes too early and wait for 5 minutes there - potentially blocking the bus stop for others and wrecking havoc with the scheduling. Much better to split these 5 minutes between the bus stops where nobody is blocked. It's like in gamedev - you don't want to optimize happy case cause you're making the situation WORSE. If your fastest frame takes 5 ms instead of 10 ms it changes nothing at best (and makes for more jerky movement at worst). If your longest frame takes 15 ms instead of 18 ms - it means you can keep consistent 60 FPS now - and that's a HUGE win.
bluGill 2y ago
This is why good back office daspatch is needed. If the bus is late slow the following but and/or add another.
ajuc 2y ago
That's why city buses have 3 or 4 double doors and there's ticket machines inside (and drivers don't sell tickets). The time to board rarely goes over 15 seconds. Compare: https://www.lubus.info/images/stories/taborbus/5122-57.jpg https://www.lubus.info/images/stories/taborbus/5122-57.jpg vs https://www.chicagobus.org/system/photos/250/large/DSC00925.jpg https://www.chicagobus.org/system/photos/250/large/DSC00925.... That's double the boarding time at every stop right there. The schedule is also designed in such a way that the bus is usually ~1 minute ahead of time and can wait for the proper time to depart from each bus stop - zeroing the randomness on each stop. If it gets too delayed on one part of the route it can catch up on next few bus stops. On intercity routes there's fewer bus stops so usually there's just 1 door and the driver sells the tickets.
bhuber 2y ago
This phenomenon consistently happened to my college bus system, but on an even worse scale. The main bus line did a loop around campus, which took ~20 min to complete and buses scheduled every 5 minutes. In reality, you got a caravan of 4 busses arriving every 20 minutes, with the first one totally full and the last practically empty.
- theluketaylor 2y ago
  When I was a teen in Calgary the transit agency was really good at dealing with issues like this during peak periods. They would pair or triple busses together and alternate stops. If someone requested the stop the drivers would radio to coordinate. Sometimes both buses would have a requested stop, but they would work together so only one bus allowed new riders on. The non-loading bus would quickly drop off passengers and leave while the other stayed behind to handle new riders. Nearly all the stops had dedicated out of traffic space for the bus, so the leap-frog maneuver was really simple. A small amount of low cost infrastructure and some operational cooperation enabled much better service.
  - a_e_k 2y ago
    Another simple strategy that I've seen is simply for the loaded bus to allow the empty bus to overtake it and go on ahead (and just stay ahead).
    - pc86 2y ago
      That sounds identical to what the Calgary busses do? You'd still need coordination between the busses to know when the loaded bus "wants" the empty one to overtake it.
      - hobo_in_library 2y ago
        The driver in the front sticks his hand out the window and waves to the one in the back
      - a_e_k 2y ago
eichin 2y ago
That's why "dispatcher" is an actual job.
slater 2y ago
Isn't that when the second bus just sits idling at one stop for 5-10 mins? That's what they do here in SF ¯\_(ツ)_/¯
amiga386 2y ago
This is https://en.wikipedia.org/wiki/Bus_bunching https://en.wikipedia.org/wiki/Bus_bunching
soperj 2y ago
If you track the busses, this should be as easy as changing one bus to "bus full" and have the emptier bus behind it picking up the passengers for a while. That will speed up the fuller bus and slow down the bus behind it.
- blahedo 2y ago
  In Chicago (I assume also other places) the leading bus will sometimes announce "after this stop this bus will run express to Western" (or wherever) "if you need a stop before then, transfer to the bus behind this one". I wish they'd do it more often, it really helps to de-bunch the bus routes.
tunesmith 2y ago
Some bus systems handle this (partially) by only allowing passengers to disembark from the lead bus. Stop, open the back door, don't open the front door, take off. I don't know either way, but the belief is that it helps smooth it out over time.
whiterock 2y ago
There are still buses that sell tickets :O May I ask where? This has been shut down years ago where I live for the time it takes as you say.
- deleted 2y ago
  [deleted]
deleted 2y ago
[deleted]
fragmede 2y ago
this is called bus bunching and is a well studied phenomenon.
remram 2y ago
This seems easily fixable for buses, since they can overtake each other. Once the empty bus is in front, it is the one arriving first to pick passengers, while the full bus empties. In practice I see buses slowing down or stopping to keep their ordering, and I don't understand why. (Of course that doesn't work for trains which can't overtake)
- fasa99 2y ago
  What do they call it with packets, "quality of service"? FIFO. It's a good plan but you have to make sure fairness is ensured. It's the same feeling as, if I go get a burger & fries, the guy behind me orders identically, burger and fries, and somehow gets served first. The instinct is to say, "what the heck, why does HE get fast service than me in a straightforwardly unfair manner?!?" So you'd need the empty bus and full bus to hit the same spot at the same time, fill the empty bus as the full one unloads. But which bus leaves first? If the former empty bus leaves first, you're being unfair QoS to the people who are seated on the full bus (which, to their perspective, at their prior stop, was the first-in-order-on bus so therefore should be the first-in-order-off bus. On the other hand, if the full bus leaves first, why did you make incoming passengers board the empty one? They should have boarded the full one to get to their destination faster. The solution, which we see in practice, is to have the empty bus wait 5 or 10 minutes and let the full one get ahead. If we are seeing rounded fairness to all parties as the priority.
  - remram 2y ago
    This makes no sense to me at all. The bus leaves when it is done unloading and loading. There is no question of fairness here, it is not like someone made the fries you were waiting for and gave them to the wrong person. In a network metaphor, you do not halt all other TCP connection on a system because one TCP connection was stalled by a lost packet, in the name of fairness. No one would ever want that. The people on the full bus can easily see that they are not moving because they are still unloading. Who would see another empty bus passing by and thinking "those people should be made to wait"? In my experience on the subway, a train will start SKIPPING STATIONS when they are bunched together, forcing me to get off and wait for another train entirely. So I don't think fairness is the reasons buses keep their order.

jjbinx007 2y ago

Also buses are more likely to let other buses out in traffic so that's another reason why you get clumps of buses arriving rather than regularly spaced ones

ajuc 2y ago
It's a law here in Poland that everybody has to let the buses leaving a bus stop to enter the lane before them. I think most people complaining about buses in this thread just live in a city where public transport isn't a priority so it barely works :/ The city buses I've seen in USA have 1 or 2 doors. It's already wrong - it makes the boarding time unnecessarily long. Then there's the tickets - drivers shouldn't be selling or checking the tickets. You should buy tickets in a ticket machine or on your smartphone. And they shouldn't be checked every time - it takes too long. Have a group of people who board random buses and check the tickets there while the bus is driving so as not to waste anybody's time. Bus schedules and routes should be designed with randomness in mind. There should be a small buffer (1 minute is enough if boarding is quick) to zero the randomness on each bus stop. Most bus stops should be mandatory so that 3 consecutive bus stops without passangers don't wreck the whole schedule (and then it spreads to other buses because you have to wait for 5 minutes at a bus stop for your departure time and you block entrance for other buses' passangers which makes boarding longer). If you just put an intercity bus (that can work with 1 door and driver selling the tickets) and use it as a city bus that stops every 1-5 minutes - it won't work. City buses should be optimized for latency not throughput.

Ylpertnodi 2y ago

>the longer the bus has to spend picking them all up and selling them tickets etc. In my country, apart from an app/ online, you can buy a ticket pretty much anywhere. I guess someone worked out that bus drivers with money are a potential theft risk, and also that selling tickets on the bus takes time and makes busses late(r than they would be).

matrix2003 2y ago
As a rider, I also just find it more convenient to buy tickets in an app. I can link my payment method, and purchase tickets in seconds whenever I’m ready.
bluGill 2y ago
If you rarely ride though cash is easier. I won't use the app again so I don't want it. Fortunately in the us multiples of $1 are good price points so exact change put it in the safe works well.
jerlam 2y ago
The slickest process I've seen is to just swipe your credit card, without any setup whatsoever.
- jmm5 2y ago
  tap
- SoftTalker 2y ago
  Often the most expensive though. You're paying the highest individual fare rate, possibly plus card processing fees. If you buy a transit pass or use their app you can get significant discounts.
  - grkvlt 2y ago
    in big cities in the uk (edinburgh, london, etc.) paying with a contactless tap of a debit card each journey will never result in paying more than the cheapest daily, weekly etc. travel pass. single tickets are gbp 2.00 and a daaily pass is gbp 5.00 so individual journeys are recorded and counted (when paid for with the same card, obviously) and at the end of the day, if more than three journeys have been made the total charge for the day is capped at gbp 5.00 - and the weekly total is also capped at the value of a weekly pass, etc.

mitthrowaway2 2y ago

That bus with more riders on board also has a higher probability of needing to stop to let people off at each location as well, slowing it down even further!

ajuc 2y ago
This is part of a good route design - most bus stops should be "mandatory" - which means the bus stops there no matter what. Some bus stops are "optional" - driver only stops there if there's somebody waiting or if somebody in the bus presses the "STOP" button near the doors. It's marked on the timetable which bus stop is optional. It's not worth it to make every stop optional because then the routes become too unpredictable and scheduling is hard. Usually there's like 5-10% of optional bus stops on each route - only in the places where very few people get in/out.
- leereeves 2y ago
  OTOH, it's extremely annoying to sit on a stopped bus when no one is boarding or leaving. That discourages use of mass transit.
  - ajuc 2y ago
    It takes like 10 seconds. And you have to keep the schedule anyway - if you skip this bus stop you'll be waiting at the next one longer.
- mitthrowaway2 2y ago
  For express or intercity busses, that makes sense, but for high-frequency regular bus routes, I can't imagine that working. It means thar bus stops would have to be extremely sparse, or else the bus trips would need to be extremely slow.
  - ajuc 2y ago
    Exactly the opposite. It sucks for intercity buses, cause there's no point. Bus stops are rare and buses don't "bunch up". It's essential for city buses. This is how it works in every big city in Poland, it's working great. More cities started to use this system over time, because it improves the scheduling so much. The point of city buses is that they drive in traffic anyway - they rarely drive over 50 km/h and they stop every 5 minutes. How regular they are is MUCH more important than how fast they drive. If you skip 3 stops because nobody waited there - you get to the 4th bus stop 5 minutes too early and wait for 5 minutes there - potentially blocking the bus stop for others and wrecking havoc with the scheduling. Much better to split these 5 minutes between the bus stops where nobody is blocked. It's like in gamedev - you don't want to optimize happy case cause you're making the situation WORSE. If your fastest frame takes 5 ms instead of 10 ms it changes nothing at best (and makes for more jerky movement at worst). If your longest frame takes 15 ms instead of 18 ms - it means you can keep consistent 60 FPS now - and that's a HUGE win.

bluGill 2y ago

This is why good back office daspatch is needed. If the bus is late slow the following but and/or add another.

ajuc 2y ago

That's why city buses have 3 or 4 double doors and there's ticket machines inside (and drivers don't sell tickets). The time to board rarely goes over 15 seconds. Compare: https://www.lubus.info/images/stories/taborbus/5122-57.jpg https://www.lubus.info/images/stories/taborbus/5122-57.jpg vs https://www.chicagobus.org/system/photos/250/large/DSC00925.jpg https://www.chicagobus.org/system/photos/250/large/DSC00925.... That's double the boarding time at every stop right there. The schedule is also designed in such a way that the bus is usually ~1 minute ahead of time and can wait for the proper time to depart from each bus stop - zeroing the randomness on each stop. If it gets too delayed on one part of the route it can catch up on next few bus stops. On intercity routes there's fewer bus stops so usually there's just 1 door and the driver sells the tickets.

bhuber 2y ago

This phenomenon consistently happened to my college bus system, but on an even worse scale. The main bus line did a loop around campus, which took ~20 min to complete and buses scheduled every 5 minutes. In reality, you got a caravan of 4 busses arriving every 20 minutes, with the first one totally full and the last practically empty.

theluketaylor 2y ago
When I was a teen in Calgary the transit agency was really good at dealing with issues like this during peak periods. They would pair or triple busses together and alternate stops. If someone requested the stop the drivers would radio to coordinate. Sometimes both buses would have a requested stop, but they would work together so only one bus allowed new riders on. The non-loading bus would quickly drop off passengers and leave while the other stayed behind to handle new riders. Nearly all the stops had dedicated out of traffic space for the bus, so the leap-frog maneuver was really simple. A small amount of low cost infrastructure and some operational cooperation enabled much better service.
- a_e_k 2y ago
  Another simple strategy that I've seen is simply for the loaded bus to allow the empty bus to overtake it and go on ahead (and just stay ahead).
  - pc86 2y ago
    That sounds identical to what the Calgary busses do? You'd still need coordination between the busses to know when the loaded bus "wants" the empty one to overtake it.
    - hobo_in_library 2y ago
      The driver in the front sticks his hand out the window and waves to the one in the back
    - a_e_k 2y ago

eichin 2y ago

That's why "dispatcher" is an actual job.

slater 2y ago

Isn't that when the second bus just sits idling at one stop for 5-10 mins? That's what they do here in SF ¯\_(ツ)_/¯

amiga386 2y ago

This is https://en.wikipedia.org/wiki/Bus_bunching https://en.wikipedia.org/wiki/Bus_bunching

soperj 2y ago

If you track the busses, this should be as easy as changing one bus to "bus full" and have the emptier bus behind it picking up the passengers for a while. That will speed up the fuller bus and slow down the bus behind it.

blahedo 2y ago
In Chicago (I assume also other places) the leading bus will sometimes announce "after this stop this bus will run express to Western" (or wherever) "if you need a stop before then, transfer to the bus behind this one". I wish they'd do it more often, it really helps to de-bunch the bus routes.

tunesmith 2y ago

Some bus systems handle this (partially) by only allowing passengers to disembark from the lead bus. Stop, open the back door, don't open the front door, take off. I don't know either way, but the belief is that it helps smooth it out over time.

whiterock 2y ago

There are still buses that sell tickets :O May I ask where? This has been shut down years ago where I live for the time it takes as you say.

deleted 2y ago
[deleted]

deleted 2y ago

[deleted]

fragmede 2y ago

this is called bus bunching and is a well studied phenomenon.

remram 2y ago

This seems easily fixable for buses, since they can overtake each other. Once the empty bus is in front, it is the one arriving first to pick passengers, while the full bus empties. In practice I see buses slowing down or stopping to keep their ordering, and I don't understand why. (Of course that doesn't work for trains which can't overtake)

fasa99 2y ago
What do they call it with packets, "quality of service"? FIFO. It's a good plan but you have to make sure fairness is ensured. It's the same feeling as, if I go get a burger & fries, the guy behind me orders identically, burger and fries, and somehow gets served first. The instinct is to say, "what the heck, why does HE get fast service than me in a straightforwardly unfair manner?!?" So you'd need the empty bus and full bus to hit the same spot at the same time, fill the empty bus as the full one unloads. But which bus leaves first? If the former empty bus leaves first, you're being unfair QoS to the people who are seated on the full bus (which, to their perspective, at their prior stop, was the first-in-order-on bus so therefore should be the first-in-order-off bus. On the other hand, if the full bus leaves first, why did you make incoming passengers board the empty one? They should have boarded the full one to get to their destination faster. The solution, which we see in practice, is to have the empty bus wait 5 or 10 minutes and let the full one get ahead. If we are seeing rounded fairness to all parties as the priority.
- remram 2y ago
  This makes no sense to me at all. The bus leaves when it is done unloading and loading. There is no question of fairness here, it is not like someone made the fries you were waiting for and gave them to the wrong person. In a network metaphor, you do not halt all other TCP connection on a system because one TCP connection was stalled by a lost packet, in the name of fairness. No one would ever want that. The people on the full bus can easily see that they are not moving because they are still unloading. Who would see another empty bus passing by and thinking "those people should be made to wait"? In my experience on the subway, a train will start SKIPPING STATIONS when they are bunched together, forcing me to get off and wait for another train entirely. So I don't think fairness is the reasons buses keep their order.