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Why Do Buses Bunch?

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Re: Why Do Buses Bunch?

#61

Post by inferiorhuman »

tim333 wrote: post #10
caymanjim wrote: post #7

This is very common in Manhattan. Whenever I saw a full bus, I'd skip it and wait for the next one, because it was almost certainly going to come along within 5 minutes and be pleasantly uncrowded. On a busy route, it's the sensible choice. On longer-distance commuter routes, where the scheduled times are 30-60 minutes apart, I wouldn't usually take a chance on waiting for the next one, but I even did that on occasio…

It's mostly been fixed in London. They used to be famous for no busses for 20 mins then 3 at once but they are now controlled by a central computer system which knows all the positions via gps and cell data.

That's fascinating. Are there any writeups on it?

Re: Why Do Buses Bunch?

#62

Post by victor9000 »

adrianmonk wrote: post #26

Would it help to have the trailing bus pass the leading bus when they bunch up? My reasoning: (1) As the article said, full buses move slower because more passengers means more boarding/unboarding time at stops. (2) The lead bus is the fuller, slower one. Slower bus in front means buses get closer together. (3) If one bus passes the other, then you have the faster bus in front and the slower one behind. They should t…

A few more points regarding (1). The longer a bus takes to arrive, the more people will accumulate at the next stop, thus compounding the problem. Also, all people don't board the bus at the same speed. The more people that accumulate, the higher likelihood you have of getting an outlier when it comes to boarding time (wheelchair, elderly, bikes, etc). So the later a bus runs, the later it's likely to be.

Re: Why Do Buses Bunch?

#63

Post by Aeolun »

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.

Except for all those poor people that are still in the bus when it teleports :P

Re: Why Do Buses Bunch?

#64

Post by kazinator »

massivecali wrote: post #39
kazinator wrote: post #16

Earlier quoted context omitted.

Buses don't stop at unoccupied bus-stops, unless someone dings the bell. The faster bus skipping stops where people are waiting, so they can be picked up by the next bus does work; I've seen it in action.

Which, as a patron who doesn't want to sit for an hour in the sun, is really not acceptable. The bus is not supposed to be in a race, they are supposed to make predictable stops along a predetermined route. Most bus stops I have used in the US dont have covered shelters or enough space for passengers to wait outside of the elements. Usually this means sitting under the overhang of a nearby business. If the bus doesn'…

A better future is getting a car or hopping on a bike.

Re: Why Do Buses Bunch?

#65

Post by NikkiA »

bbarn wrote: post #59
grawprog wrote: post #43

Earlier quoted context omitted.

When busses get bunched here, the lead bus just tends to skip stops and leave them for the trailing bus. This doesn't really seem to help much. They usually both stay pretty close together and, as a passenger, you end up standing there confused as to whether the bus just left you or not if you can't see the one behind.

The lead bus is much less equipped to skip a stop if it has more passengers, because there's a greater chance of a passenger needing to stop to disembark. In Chicago, you will see a trailing bus skip but it can do so because the driver hasn't gotten and cord-pulls to signal someone getting off.

That depends on how many/how frequent your stops are. Here in the north of the UK, a 30 minute journey on an urban bus could pass 60-80 stops, many of which will see no-one wanting to get on/off

Re: Why Do Buses Bunch?

#66

Post by kazinator »

cimmanom wrote: post #34
kazinator wrote: post #16

Earlier quoted context omitted.

Buses don't stop at unoccupied bus-stops, unless someone dings the bell. The faster bus skipping stops where people are waiting, so they can be picked up by the next bus does work; I've seen it in action.

Bunching happens most often with crowded buses and results in the front bus in a cluster becoming crowded. Crowded buses are most likely to have people getting off at every stop. The ones I take often have people ringing for every stop even when nearly empty.

Depends where. Suppose it's the evening rush hour, and the bus route is along a business district, headed toward a train station. The bus is basically picking people up at multiple locations and then everyone gets off at the station.

Re: Why Do Buses Bunch?

#67

Post by NikkiA »

Taniwha wrote: post #46
adrianmonk wrote: post #26

Would it help to have the trailing bus pass the leading bus when they bunch up? My reasoning: (1) As the article said, full buses move slower because more passengers means more boarding/unboarding time at stops. (2) The lead bus is the fuller, slower one. Slower bus in front means buses get closer together. (3) If one bus passes the other, then you have the faster bus in front and the slower one behind. They should t…

Of course trolley buses (or streetcars/trams) can't do this

Trolley buses usually can to an extent - the trolley arm can usually handle the 3m swing or so it takes to pass another bus.

Re: Why Do Buses Bunch?

#68

Post by NikkiA »

komali2 wrote: post #32
adrianmonk wrote: post #26

Would it help to have the trailing bus pass the leading bus when they bunch up? My reasoning: (1) As the article said, full buses move slower because more passengers means more boarding/unboarding time at stops. (2) The lead bus is the fuller, slower one. Slower bus in front means buses get closer together. (3) If one bus passes the other, then you have the faster bus in front and the slower one behind. They should t…

My first thought is that this would break a shitload of software around bus time indicators - i.e. on bus stops and presumably whatever API the website talks to. I believe the buses function like trains in that sense - they're numbered not just by route, but by actual bus. Would be nice though.

The 'next bus' signs around here are all based on realtime GPS-tracking from the buses ('free wifi' is often piggy backed on the data connection the bus thus has to maintain.

I've seen buses run so late that they bunch-up and even to the point where they asked us to switch to the front bus so the rear bus could be taken out of service, once, and never seen the displays at the stops get too confused.

Re: Why Do Buses Bunch?

#70

Post by thtthings »

adrianmonk wrote: post #26

Would it help to have the trailing bus pass the leading bus when they bunch up? My reasoning: (1) As the article said, full buses move slower because more passengers means more boarding/unboarding time at stops. (2) The lead bus is the fuller, slower one. Slower bus in front means buses get closer together. (3) If one bus passes the other, then you have the faster bus in front and the slower one behind. They should t…

They all don't go to the same destination. They have an overlap of route but all of them go to different destinations. So you cannot just skip a bus stop. You are very rarely if ever going to see the same numbered buses bunched together
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