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Why Do Buses Bunch?

setosa.io

81–90 of 153 posts

Re: Why Do Buses Bunch?

#81
post #77

On busy routes one solution is to have longer buses and allow passengers to enter and exit in all doors. In Gothenburg they run these buses on certain routes: https://sv.wikipedia.org/wiki/Stombussar_i_G%C3%B6teborg#/me...

How's this any better? Now instead of having two or three buses that sometimes bunch up, you have 1 bus that's (essentially) always bunched up.

Re: Why Do Buses Bunch?

#82
post #75

Earlier quoted context omitted.

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

https://en.wikipedia.org/wiki/IBus_(London) is part of it. Also https://www.intelligenttransport.com/transport-articles/688/... http://www.eltis.org/sites/default/files/case-studies/docume... It's not actually clear if the de-bunching is algorithms or humans: >Headway information, the time gap between consecutive buses, will be available to a bus driver at all times on a screen so that they can make decisions such as…

Either way that's a great use of technology. AVLs and annunciators aren't exactly new technology (both exist with SF's Muni, for instance), but the MTA has definitely not used this data to avoid bunching — even in the subway.

Re: Why Do Buses Bunch?

#83
post #81
post #77

On busy routes one solution is to have longer buses and allow passengers to enter and exit in all doors. In Gothenburg they run these buses on certain routes: https://sv.wikipedia.org/wiki/Stombussar_i_G%C3%B6teborg#/me...

How's this any better? Now instead of having two or three buses that sometimes bunch up, you have 1 bus that's (essentially) always bunched up.

It comes one every five minutes during rush hours. You'll increase capacity by around 50%. Don't see how a longer bus will bunch up more?

Re: Why Do Buses Bunch?

#84

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…

You are forgetting people who would want to get off that stop, so this is may not be an option.

The lead bus can slow down between stops and let the empty bus overtake. Essentially "stop" several bus-lengths before the next stop and let the empty bus overtake and pull into the stop ahead of it.

The full bus pulls in directly behind the lead bus and lets passengers out.

Re: Why Do Buses Bunch?

#85

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…

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.

Re: Why Do Buses Bunch?

#86
post #42

Earlier quoted context omitted.

Both buses probably need to drop off passengers, though (who would likely be a lot more enraged than people who don't get picked up by the first bus if they didn't get out where they wanted). Anyway, I think the leading bus skips stops when possible, at least here. I don't think people mind that too much, because for all they know, the bus might simply be too full, although that certainly only happens on exceptional…

The London Underground sometimes skips stops in order to uncongest lines after a temporary delay. They tell everyone on the trains that will be skipping stops that it's happening, and anyone who wants the intermediate stops has to get off and catch the next one. This probably wouldn't work for buses that take a lot longer to load/unload though...

This is amazing! I wish the DC Metro did this.

Re: Why Do Buses Bunch?

#87

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…

You are forgetting people who would want to get off that stop, so this is may not be an option.

That bus stop but in front of the slow bus.

Re: Why Do Buses Bunch?

#88

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 do that here in Seattle sometimes.

Re: Why Do Buses Bunch?

#89
post #25

Earlier quoted context omitted.

That app was built by a UW student and uses estimated data based on the schedule, as far as I know. It's not accurate... unless things have changed in the last year or so since I moved.

When that app (OneBusAway) first came out, it was extremely accurate. It completely went to crap when Metro took over maintenance.

It's very accurate now. I don't know when your experience with it was.

It pulls from the same source that Google Maps currently does, so feel free to use whichever you prefer.

Re: Why Do Buses Bunch?

#90
post #59

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.

The one that came to mind as I wrote that was the one I take after work. Most people tend to get off at the train station at the last stop so the bus only really stops for pickups, other than occasionally. The bus goes through an area mostly full of offices and industrial type buildings until it reaches the train station. There's not much inbetween but the same thing tends to happen. Even on other routes here though, busses tend to do the same thing when they're bunched.
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