On a tangental note, another HN user posted another visualisation a few months back which I quite enjoyed: Why do buses bunch? : http://setosa.io/bus/
Yep and I also went to University of Pittsburgh. Not a coincidence.
Pittsburgh Bus Bunching (2016)
51–60 of 64 posts
Re: Pittsburgh Bus Bunching (2016)
#52On a tangental note, another HN user posted another visualisation a few months back which I quite enjoyed: Why do buses bunch? : http://setosa.io/bus/
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on driving to stay on time. The problem will be worse the more frequent the service is.
The solution is also very simple. Stop the waiting time at each bus stop depending on the number of passengers that get on or off. Slacken the timetable, so that every few stops the bus waits for a minute to match the schedule.
On bus routes with very frequent service, for instance every 10 minutes or more frequent, there is no longer really any need to have a timetable - it will be a bigger win for the customer to just make sure the buses don't bunch than it is to actually publish a timetable. In this case, you may want to implement a negative feedback loop based on vehicle tracking. Most buses are remotely tracked now anyway, so it shouldn't be too hard to return a signal to each bus saying either "carry on as normal" or "you're too close to the bus in front, wait a bit at the next stop".
This is basically the one problem that needs to be solved for buses to not be rubbish, and it is so simple to do so.
Re: Pittsburgh Bus Bunching (2016)
#53> 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.
They already do that in NYC. It doesn’t help because the following stops are full of extra passengers and the crowds on the buses quickly equalize while they remain bunched.
I didn't state it that clear, but I am well aware that adding overtaking to the equation doesn't solve the bunching problem .
But the bunching itself is not a problem. The problems are the effects it causes like:
1. crowded busses
2. arrival delays
Overtanking has a major impact on the first effect as you have stated too, the 'crowds on the buses quickly equalize'. The impact on the second effect depends on some other parameters. If all busses are crowded there will be no effect at all, but if only a few busses are crowded (the front busses) and the busses behind them are empty, there can be a positive effect on the arrival delays too (the worst case drop off time will be lower).
So I would not say 'it does not help' as it certainly decreases the negative effects.
Re: Pittsburgh Bus Bunching (2016)
#54Earlier quoted context omitted.
As a bus rider whose drivers on one route sometimes do this, I loathe it. The problem is that the route timing is designed for a specific traffic and ridership level. The actual time to run the route can vary by a factor of 3 or more depending on whether it’s before, during, or after rush hour. The route timing is designed for after rush hour traffic levels, when it takes about 45-50 min to travel from my stop to my…
I probably didn't do a good job of explaining it, but fixing the schedule was part of the suggestion. So for your example, rush hour timing would allow ~50 minutes between your stops, then after that only 20 minutes.
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Re: Pittsburgh Bus Bunching (2016)
#55Love 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…
Buses are typically late due to variations in traffic. The solution is to prioritize bus traffic. Use dedicated bus lanes. Cars could drive in the bus lane, but must pull over or switch lanes if a bus is approaching. Traffic signals switch to green when a bus is approaching.
Not only does Pittsburgh have dedicated bus lanes, they also have dedicated bus roads; roads where cars are not allowed to drive on (many are deprecated light rail lines)
Re: Pittsburgh Bus Bunching (2016)
#56On a tangental note, another HN user posted another visualisation a few months back which I quite enjoyed: Why do buses bunch? : http://setosa.io/bus/
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on…
> "you're too close to the bus in front, wait a bit at the next stop"
That's one way to infuriate the passengers on the waiting bus.
Re: Pittsburgh Bus Bunching (2016)
#57On a tangental note, another HN user posted another visualisation a few months back which I quite enjoyed: Why do buses bunch? : http://setosa.io/bus/
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on…
>and it is so simple to do so.
Except for the little hiccup of organizational politics in government bureaucracies that needs to be solved or side stepped as a prerequisite. If you can do that tons of "hard" problems are easy to solve.
Re: Pittsburgh Bus Bunching (2016)
#58Earlier quoted context omitted.
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on…
> "you're too close to the bus in front, wait a bit at the next stop" That's one way to infuriate the passengers on the waiting bus.
Not if it's something like 20 seconds.
Re: Pittsburgh Bus Bunching (2016)
#59Earlier quoted context omitted.
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on…
>and it is so simple to do so. Except for the little hiccup of organizational politics in government bureaucracies that needs to be solved or side stepped as a prerequisite. If you can do that tons of "hard" problems are easy to solve.
Most bus services that I know are private companies, so this wouldn't be a problem.
Re: Pittsburgh Bus Bunching (2016)
#60Earlier quoted context omitted.
Indeed. You can do all sorts of complicated analysis of where, when, and how frequently buses bunch. But the explanation is very simple - like magnets, buses attract each other, in a positive feedback loop. As long as the waiting time at each bus stop depends on the number of passengers that have to get on and off, then buses will always bunch. This is caused by the bus schedule being tight, so the bus has to keep on…
> "you're too close to the bus in front, wait a bit at the next stop" That's one way to infuriate the passengers on the waiting bus.
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