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learnstats2

>Note how this would all go away if the empty buses could pass the full buses.

It's more complicated than that and has to be managed carefully.

Here's what happens in the unmanaged case:

- The empty bus passes the full bus

- There are passengers waiting at the next stop

- The empty bus stops to pick them up

- There are no passengers waiting

- The full bus typically doesn't have to stop

- The full bus passes the empty bus

Now these buses are irrevocably bunched.

P.S. This site doesn't work for me at all.

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Exactly. A method that does work is to make the full bus exit-only: no new passengers are allowed to enter the bus. You keep that bus exit-only until it has caught up to its schedule. This also works fine with trolley buses. Unfortunately this is hard to match with human psychology of the people trying to enter a bus.

I've seen this happen, but it works better w/ human psychology if the buses are frequent (and people know they are frequent). If it's a bus with a typical headway of 5-10 minutes then it's generally ok; if buses only come 2-3 times per hour, being skipped to improve the spacing of buses is really annoying/inconvenient since passengers aren't confident of another bus coming soon.

An alternative sometimes used in systems that have infrequent buses is to schedule the route with some slack in the schedule, so the bus is almost always "ahead of schedule". Then it waits at certain designated timepoints until the scheduled time, which re-syncs it with the schedule. This slows down the route overall (since the bus is periodically just sitting at a timepoint for a few minutes), but improves its predictability / adherence to the published schedule. I think I first ran across this in Miami.

On routes that are heavily front-loaded (a connection from a metro line to a neighbourhood the metro doesn't reach, for example), this can result in the first five-to-ten stops on the route effectively being knocked out during rush hour. Anybody who actually wants to catch the bus has to walk ten blocks over to the first stop.

A display at the bus stop showing when the next 3-5 buses are going to stop approximately solves the problem

It really helps. In New York some subway lines have this and some do not. On the lines that do not, you sometimes hear the conductor announce "there is a train immediately behind this one" but it's not nearly as effective as when everyone waiting on the platform has been able to see that.

You would only do this during times when the throughput of the system is still higher than the arrival rate of people. It's essentially trading throughput for reduced latency. During rush hour you need throughput.

A fairly full bus will still stop at many stops (maybe not all) even if nobody is waiting to get on, because there will be people waiting to get off.

One frequent problem is with lines that run between two places (e.g. the downtown core and a stadium during a game), where virtually everybody will get on at the first stop and ride until the last stop. This plays havoc on the needs of regular commuters who live between the two stops. Usually, express runs are created that only go between the two stops, to siphon off some of that traffic—but if the regular bus arrives before the express bus, people will get on it in order to go to the terminal stop nevertheless.

Really, almost all transit problems could be solved with etiquette about not (always) getting on the first bus to arrive at your stop.

> Really, almost all transit problems could be solved with etiquette about not (always) getting on the first bus to arrive at your stop.

I think that not etiquette but rules is the solution here. If I make up my own standards of politeness for which bus I should board, then it's likely that I will inadvertently conflict with the transit system's standards, making things worse for others or for myself than the greedy approach.

To be blunt, I'm not going nobly to sacrifice my bus based on my guess of what's efficient. If, however, the transit system clearly indicated what was appropriate—via its rules—then I would be much more motivated to obey them, based on the idea that the rules would have been set up to maximise throughput. (Live status monitors, which not all cities have, also help a lot here.)

Yea, maybe not even rules -- we can do better those days than giving out a set of rules for users and expecting them to follow.

The ideal I think would be a "global optimizer" for commuter traffic (with fairness included in the objective function, i.e. nobody is screwed too much in the name of the commons), and appropriate individual-level tracking and statistics. That way you could be told:

"You should hop-in in the bus X which will take only Y minutes.", updated in real time. If you don't follow the recommendation maybe you pay a more expensive fare and the system adjusts.

> almost all transit problems could be solved with etiquette about not (always) getting on the first bus to arrive at your stop.

Spoken like someone who doesn't ride the bus.

As discussed below, it's common that people want to get off at the same place, and so not all stops are used to disembark.

Also, disembarking is much quicker than embarking[1], so this won't make a big enough difference. The bus behind will be at least as fast than the bus in front.

[1]Your choice of reasons: baby carriages don't like to go up; people have to pay to get on; the location of the bus door is/isn't predictable in advance; etc.

> P.S. This site doesn't work for me at all.

Use Chrome. Doesn't work on Firefox.

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