The Mohring effect

[ozbob]

Tramtrain posted this link in a discussion thread on the new fare strategy.   Worthy of it's own thread   

Mohring effect

http://en.wikipedia.org/wiki/Mohring_effect

Mohring effect
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The Mohring effect is a technical property of transit systems demonstrating increasing returns.

In brief, as transit frequencies increase, wait times decrease, demand increases, and transit frequencies can increase again. This is because transit schedules occur over time. If there is one bus an hour, the average wait from the desired time of departure (or schedule delay) is 30 minutes, if there are two buses an hour, the schedule delay drops to 15 minutes and so on. So the presence of an additional user increases the likelihood of additional service being provided.

The effect was named for University of Minnesota economist Herbert Mohring, who identified this property in a 1972 paper.

[Emmie]

This is interesting, Tramtrain - but the Wikiipedia article isn't all that helpful - I think I need a clearer explanation than that.

There's a similar mathematical story about why you wait ages for a bus, and then they all come along together.  Bus A is overdue; so more and more people wait for it at each stop; when it finally arrives, it takes longer to load so it gets even later; meanwhile bus B comes along a few minutes afterwards and finds no passengers waiting at the stop so it speeds up.  In the end, they (plus buses C, D, E...) are all in lockstep together.  Great.  Sounds like the Inner Northern Busway.

[#Metro]

Basically, the less time people are waiting, the more people expect to catch it.
So they all turn up, and fill the bus.
So the bus is/is almost full.

So you have to put on another one. But when you do that:
But that makes it more convenient, so more people turn up expecting to catch the bus.

So now two buses are not enough, You have to put on a third.
... and so on.

Basically: If you increase the frequency, it more people will come (generally).

Brisbanes BUZ services are a case in just this.
In the pre-BUZ era, routes were not all that full. But once the frequency was increased (and it remarketed) the passenger numbers exploded- leading to overcrowding and calls for more buses. Which made the situation worse, hence now we have bendy buses and superbuses coming on line.

Imagine what would happen if you increased train frequencies to 15min across the board?

[mufreight]

Is not the purpose of public transport to provide SAFE, reliable, ecenomic and convenient transport for commuters as an alternative to an expanding use of private cars?

[stephenk]

Stockholms Pendaltag and Croydon Tramlink are both excellent examples of increased frequency resulting in large increases in patronage.

Stockholm, Oslo, Copenhagen, Hamburg, Perth, Kyoto, Melbourne, and Rome are cities between 1m and 3.5m population which all have far better off-peak suburban rail services compared to Brisbane. It's time that Brisbane needs to catch up!

[somebody]

Stockholms Pendaltag and Croydon Tramlink are both excellent examples of increased frequency resulting in large increases in patronage.

Stockholm, Oslo, Copenhagen, Hamburg, Perth, Kyoto, Melbourne, and Rome are cities between 1m and 3.5m population which all have far better off-peak suburban rail services compared to Brisbane. It's time that Brisbane needs to catch up!

Your criteria caused Sydney to be left out.  Well, at least public transport in Brisbane is probably better than Adelaide, and definitely better than Hobart.

It's a joke.  The question is: how do we get the decision makers to see that the off peak frequency isn't up to scratch, and is also a false economy?

I would go further than previously and extend 15 min off peak frequency as far as Caboolture and Ipswich.

[Jon Bryant]

Personally I think we need to (1) change the misguided belief (break lobbyist stronghold) that the current approach to transport planning/provision will fix the current problems and (2) develop their understanding of the reality that the current approach is actually creating the problem they are trying to fix.   

Our current approach to transport planning/infrastructure development is like taking a medicine to fix an ailment when the medicine is the cause of the ailment in the first place.  If a doctor did this we would sue for malpractice.  In Transport planning we promote them!!! 

The cities leading the way in trport planning have leaders who understand the above and are driving the agenda towards PT.  Our politicians are still delivering PT as a social service.

[mufreight]

They only get promoted in this state for their failures rather than their successes, see Translink, SEQIP and Queensland Transport as prime examples for this, hence increased fares, lower standards and unreliability of service.

[#Metro]

What this suggests is that the Rail network could be improved remarkably simply:

1. Just put more trains on.

[skippy]

What this suggests is that the Rail network could be improved remarkably simply:

1. Just put more trains on.

Agree with this. I hate the notion of lengthening platforms to cater for longer trains, as it gives someone the excuse to run the same (lousy) service frequency. e.g. 3 trains / hour on Shorncliffe line in the AM peak.

Futhermore when frequency is high the reliability issue is less important. I used to live at Bondi Junction when the peak services were every 4 mins and around 10 mins off peak. The monthly newsletter used to apologise for poor reliability, however at these frequencies it never bothered me in the slightest.

[O_128]

What this suggests is that the Rail network could be improved remarkably simply:

1. Just put more trains on.

Agree with this. I hate the notion of lengthening platforms to cater for longer trains, as it gives someone the excuse to run the same (lousy) service frequency. e.g. 3 trains / hour on Shorncliffe line in the AM peak.

Futhermore when frequency is high the reliability issue is less important. I used to live at Bondi Junction when the peak services were every 4 mins and around 10 mins off peak. The monthly newsletter used to apologise for poor reliability, however at these frequencies it never bothered me in the slightest.

i used to live in north sydney and had the same thing when the frequency is that good it doesnt matter. where as even at equiviant stations such as park raod there are big gaps

[Jon Bryant]

Agree totally.  Frequency needs to be increased on existing lines to frequecnies like Perth http://backontrack.org/mbs/index.php?topic=2914.0.  They reach close to a train every 5-6 minutes.  The key is to also keep this going morning, noon and nigght so that people can move in and out of the CBD all hours as our current system is CBD centric.

[O_128]

Agree totally.  Frequency needs to be increased on existing lines to frequecnies like Perth http://backontrack.org/mbs/index.php?topic=2914.0.  They reach close to a train every 5-6 minutes.  The key is to also keep this going morning, noon and nigght so that people can move in and out of the CBD all hours as our current system is CBD centric.

we really need to upgrade the now ancient signalling system

[#Metro]

Some information on the power of frequency upgrades, from the Thredbo transport site (yes, the one Hensher runs)

http://www.thredbo.itls.usyd.edu.au/downloads/thredbo10_papers/thredbo10-themeA-Warren.pdf

Well worth a read. Now if this could only be done for rail!