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Why Do Buses Bunch?

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Re: Why Do Buses Bunch?

#101

Post by btbuildem »

jpatokal wrote: post #92
dominotw wrote: post #85

Earlier quoted context omitted.

This is possible with public transportation too. Trains run express and skip stops all the time. I think that would be too much hassle with buses but it's possible.

I have seen full or near-full buses skip scheduled stops to alleviate this. Although from a waiting passenger's POV, having an already delayed bus that has space left zoom past you without stopping is pretty infuriating...!

Perhaps the bus that caught up to the full bus should pass it, and relieve the next stop - presumably there are extra passengers waiting at that one too, since the bus is late.

This way the bus that caught up will now risk slowing down (dealing with fuller stops), but the original full bus that was slow is likely to not speed up that much, having an above-average number of potentially disembarking passengers.

Re: Why Do Buses Bunch?

#102

Post by mattlondon »

jpatokal wrote: post #94
djsumdog wrote: post #18

Earlier quoted context omitted.

If you're at a bad rail stop (like the first one outside of the central part of a city going outbound at rush hour) it's not uncommon to have to wait two or three trains just to be able to board. In a city like Singapore or London it might not be too long since many of their trains are automated (in Singapore they're all automated/driverless) and the busy lines are allocated enough cars to arrive 1 minute apart or le…

I'm not aware of any metro system in the world that has scheduled headways of under a minute. The Moscow Metro was tops for a long time with 95-second headways on some lines at peak (without full automation, mind you), but Paris Metro Line 1 was recently fully automated and can go as low as 85 seconds. Singapore currently has 120 second headways on its busiest line (East/West, which is not automated) and is working o…

Victoria line on the London underground does 100 seconds, with plans for the Northern Line to reach that too FWIW.

Doesn't really help much though. Sometimes you still have to wait 2 or 3 (or more!) trains before you can get to the front of the platform edge so that you can actually get on though!

Re: Why Do Buses Bunch?

#103

Post by unixhero »

dmoy wrote: post #8
telesilla wrote: post #6

Thanks for letting me relive nightmare memories of Grand Ave in Chicago! I always wondered, why couldn't the bus drivers be in communication and have the front bus just skip a couple of stops (where people are waiting) when they bunched, which was often even 3 buses!

If nobody signals to get off, buses sometimes will skip if they're bunched. I've seen it in at least three cities before. I have no idea if it's policy or if the drivers on those routes juts took matters into their own hands. I see bunched buses on the stop right outside my work basically every day. Sometimes four from one route and another three from another parallel route all within a ~5 minute span. Mercer in Seat…

Not stopping when nobody signals is the point of the signal right:).

Re: Why Do Buses Bunch?

#104

Post by m463 »

phinnaeus wrote: post #56
brian_cloutier wrote: post #54

I enjoyed the callout to this when I was reading Google's Percolator paper a few years ago: > The random-scanning approach requires one additional tweak: when it was first deployed we noticed that scanning threads would tend to clump together in a few regions of the table, effectively reducing the parallelism of the scan. This phenomenon is commonly seen in public transportation systems where it is known as “platooni…

TL;DR - Teleportation will solve public transit problems.

if teleportation is impractical you could just use a faster bus, like USB 3.0 or more lanes like PCIe

Re: Why Do Buses Bunch?

#105

Post by telesilla »

massivecali wrote: post #79
ambicapter wrote: post #76

Earlier quoted context omitted.

We're talking about bus bunching here. The bus is skipping your stop because there's an empty one right behind it.

This is great in theory, but not in practice. A bus in back sees the bus in front stop so it passes. However the bus in front might be full and only drops off one pasenger while more than one pasenger is waiting to board and are thus denied. Again, simple dismissal of the problem is ignorant of reality.

This is why I mentioned communication: surely there is a system that drivers could implement themselves with a code or something.

Re: Why Do Buses Bunch?

#106

Post by mjevans »

jpatokal wrote: post #92
dominotw wrote: post #85

Earlier quoted context omitted.

This is possible with public transportation too. Trains run express and skip stops all the time. I think that would be too much hassle with buses but it's possible.

I have seen full or near-full buses skip scheduled stops to alleviate this. Although from a waiting passenger's POV, having an already delayed bus that has space left zoom past you without stopping is pretty infuriating...!

Yeah, the correct customer service solution is to have the full bus HOLD at a stop and let the emptier bus leave first (and stay ahead).

Re: Why Do Buses Bunch?

#107

Post by adrianN »

mjevans wrote: post #106
jpatokal wrote: post #92

Earlier quoted context omitted.

I have seen full or near-full buses skip scheduled stops to alleviate this. Although from a waiting passenger's POV, having an already delayed bus that has space left zoom past you without stopping is pretty infuriating...!

Yeah, the correct customer service solution is to have the full bus HOLD at a stop and let the emptier bus leave first (and stay ahead).

That delays all people who are already on the delayed bus even more.

Re: Why Do Buses Bunch?

#108

Post by nobrains »

"Why do Buses Come in Threes"

I read this book when I was 12 which opened up my mind to the hidden maths of everyday life.

I recommend to read this book, even as adults, but HIGHLY recommend to give to children to let them read about and discover coincidences like common birthdays, fractals in nature and many others.

Author link: http://www.robeastaway.com/books/why-do-buses-come-in-threes

Goodreads: https://www.goodreads.com/book/show/1225641.Why_Do_Buses_Com...

(Not including Amazon link on purpose)

Re: Why Do Buses Bunch?

#110

Post by icebraining »

zhte415 wrote: post #80
brian_cloutier wrote: post #54

I enjoyed the callout to this when I was reading Google's Percolator paper a few years ago: > The random-scanning approach requires one additional tweak: when it was first deployed we noticed that scanning threads would tend to clump together in a few regions of the table, effectively reducing the parallelism of the scan. This phenomenon is commonly seen in public transportation systems where it is known as “platooni…

> To further the transportation analogy, the buses (scanner threads) in our city avoid clumping by teleporting themselves to a random stop (location in the table) if they get too close to the bus in front of them. Subway trains do this "to regulate service" iirc is the term used on the London Underground. Takt time［1］and Drum Buffer Rope［2］both related concepts of regulating flow through a process/system. ［1］ https:/…

London subway trains teleport themselves?
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