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Pittsburgh Bus Bunching (2016)

bunching.github.io

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Re: Pittsburgh Bus Bunching (2016)

#31

Post by Cthulhu_ »

remarkEon wrote: post #18

Love this. I’ve experienced bus bunching in several cities at this point (LA, DC, and now Seattle). It seems to be a known failure mode of metro transit planning. First step is understanding what your problem space looks like. Curious to know what anyone here thinks could be a solution. I doubt skipping stops is one. I suspect that speed controls are probably the way to go. Edit: kudos to doing this in R. I’ve done o…

Skipping stops is something our buses used to do (rural Netherlands), this would usually happen if one bus was late so the next one was right behind it. Makes no sense for a full bus to stop when nobody has to get out when there's an empty one driving the same route right behind it.

Experienced bus travelers would often know when there'd be two buses in a row, too. And of course the bus drivers would point it out.

Re: Pittsburgh Bus Bunching (2016)

#32

Post by [deleted] »

arendtio wrote: post #20

> how do we make this better? Just teach the bus drivers to let the empty busses overtake the crowded one. It won't solve the pauses when there will be no bus coming, but at least it increases the passenger comfort by a good margin and the average speed by which the bunch travels increases too.

[deleted]

Re: Pittsburgh Bus Bunching (2016)

#33

Post by scandox »

In Dublin (Ireland) the drivers at Dublin Bus call this polling (or poling...not sure of spelling).

The explanation given to me by a former driver is very simple. When a driver is very hungover or in bad form for one reason or another they poll the other bus so they get light duty.

Re: Pittsburgh Bus Bunching (2016)

#34

Post by andreareina »

remarkEon wrote: post #18

Love this. I’ve experienced bus bunching in several cities at this point (LA, DC, and now Seattle). It seems to be a known failure mode of metro transit planning. First step is understanding what your problem space looks like. Curious to know what anyone here thinks could be a solution. I doubt skipping stops is one. I suspect that speed controls are probably the way to go. Edit: kudos to doing this in R. I’ve done o…

Disclaimer: not a transportation engineer.

I wonder what it would look like if departure times were enforced in the don't-leave-before direction. Then giving enough time between scheduled stops that e.g. 90% of buses traveling that stretch can make it in time for that day/time combination. I realize that doesn't mean that 90% of trips will be on-time due to how failures will cascade, but it should eventually catch up due to the slack provided.

The big question is whether people will accept the increased latency (and total trip times) for less variance in waiting time and trip time.

Re: Pittsburgh Bus Bunching (2016)

#35

Post by kingosticks »

remarkEon wrote: post #16
cup-of-tea wrote: post #12

Earlier quoted context omitted.

Do they really stop everywhere unconditionally? In the UK almost all stops are by request, for both boarding and alighting.

As another comment noted, even if the stops aren’t unconditional the probability that no one will pull the cord for any particular stop on a crowded bus is near zero.

But then it's a simple case of the front bus not letting anyone on (only opens it's rear doors). Everyone then gets on the 2nd bus. The people become spread out between the buses and the probability of not always needing to stop increases. That does obviously only work where your bus design allows it and also to some extent, your drivers being wise to it.

Re: Pittsburgh Bus Bunching (2016)

#36

Post by remarkEon »

andreareina wrote: post #34
remarkEon wrote: post #18

Love this. I’ve experienced bus bunching in several cities at this point (LA, DC, and now Seattle). It seems to be a known failure mode of metro transit planning. First step is understanding what your problem space looks like. Curious to know what anyone here thinks could be a solution. I doubt skipping stops is one. I suspect that speed controls are probably the way to go. Edit: kudos to doing this in R. I’ve done o…

Disclaimer: not a transportation engineer. I wonder what it would look like if departure times were enforced in the don't-leave-before direction. Then giving enough time between scheduled stops that e.g. 90% of buses traveling that stretch can make it in time for that day/time combination . I realize that doesn't mean that 90% of trips will be on-time due to how failures will cascade, but it should eventually catch u…

I suspect they would. Predictability in public transit is hugely important. People base a lot of their routines on these schedules. I also think enforcing stop/departure times is probably a much more elegant solution than controlling speed.

Re: Pittsburgh Bus Bunching (2016)

#37

Post by remarkEon »

arendtio wrote: post #27
remarkEon wrote: post #24

Earlier quoted context omitted.

I suspect this isn’t as easy as you think. Where I am (Seattle) an empty bus overtaking a full one isn’t really feasible given traffic and lane size considerations.

Well, maybe you should consider banning cars from the city center then. ;-) I mean, where I live, busses manage to overtake in a one lane for each direction scenario (which is theoretically complicated, but works out in practice as traffics lights can give you chances to use the opposite lane). Nevertheless, what is important is that the front bus waits until the busses behind him have taken the lead. Otherwise there…

I don’t think banning cars would do much, to be honest. Banning cars might actually exacerbate the problem as the folks who would otherwise drive out of convenience now take the bus. Structurally, on many streets there literally just isn’t another lane available for an empty bus to overtake a full one. Getting rid of more cars, while a noble goal imo, won’t fix that.

Re: Pittsburgh Bus Bunching (2016)

#38

Post by remarkEon »

kingosticks wrote: post #35
remarkEon wrote: post #16

Earlier quoted context omitted.

As another comment noted, even if the stops aren’t unconditional the probability that no one will pull the cord for any particular stop on a crowded bus is near zero.

But then it's a simple case of the front bus not letting anyone on (only opens it's rear doors). Everyone then gets on the 2nd bus. The people become spread out between the buses and the probability of not always needing to stop increases. That does obviously only work where your bus design allows it and also to some extent, your drivers being wise to it.

Controlling which doors open as dependent on how full the route is and how bunched the buses are is just going to confuse passengers and make for a horrible rider experience. I sympathize with the idea though, as veteran riders know to move to the back as the bus nears your stop.

Re: Pittsburgh Bus Bunching (2016)

#40

Post by kingosticks »

remarkEon wrote: post #38
kingosticks wrote: post #35

Earlier quoted context omitted.

But then it's a simple case of the front bus not letting anyone on (only opens it's rear doors). Everyone then gets on the 2nd bus. The people become spread out between the buses and the probability of not always needing to stop increases. That does obviously only work where your bus design allows it and also to some extent, your drivers being wise to it.

Controlling which doors open as dependent on how full the route is and how bunched the buses are is just going to confuse passengers and make for a horrible rider experience. I sympathize with the idea though, as veteran riders know to move to the back as the bus nears your stop.

I mentioned it as it's what sometimes happens in London when the bus is very crowded. They do it because at the point it makes sense the rider experience is already horrible. For most buses it is front doors for getting on and rear (middle) for off. It's already independently controlled so it is not extra complication. But I do appreciate other places don't have the same system.
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