Buses, queueing theory and smart phones

I comments on my previous post on Metrobuses and small improvements in public transport BruceT gave a complaint about waiting and then giving up because of the uncertainty about when one would actually arrive on a weekend when the frequency was lower.

This reminded me of the way waiting for a late train is much less frustrating than waiting for a late bus. When waiting for a train there’s an ETA on an electronic board, ticking down (and frequently up) and at larger stations there’s announcements. Recently, when a train is late they give updates on the current location of the late service as junctions are tripped along the line. Despite the fact these ETAs are often wildly variable, move up and down, and that the announcements are restricted in the information they give, it does improve things a great deal.

This isn’t a surprise. It comes right out of queuing research. Tom Vanderbilt has a good popular treatment in Traffic – an improbably fascinating book on driving and congestion. Congestion after all is merely queuing to use the road up ahead. One of the findings discussed is that a wait with some estimation of duration and some semblance of progress is perceived as shorter and less frustrating by the waiting. Even if there is no improvement in real punctuality, the reduction in frustration is both real and quite significant. This is worth a great deal, and I think it can be achieved quite inexpensively.

Contrast the train station with a late service at a bus stop. Is it coming in a minute? 10 minutes? Was it canceled? Should I walk? If I walk won’t it just come roaring past as soon as I’ve gone 100 metres? Even the wildly rough ETAs of the train system are better than that. Any kind of idea of where the bus is is better than that.

But increasingly we have an opportunity to offer this to the waiting. It’s reasonable to assume that smart phones will become more and more ubiquitous. Certainly large proportions of the population are convinced that they’re a pointless yuppie affectation and conspicuous consumption that no normal person would use – just like mobile phones in general and personal computers were once. I think it’s also reasonable to assume that wireless speed will increase to something reasonable and access prices will fall.

And GPS technology is already ridiculously cheap. This means that transport authorities can not just offer status updates by phone, but they can offer he exact location of your late service on a map – you can watch it crawling towards you. As far as I’m concerned transit authorities should be producing this kind of data anyway. The technology is cheap and it would help them find bottlenecks and other problems that reduce punctuality. Offering it to the public won’t add much cost. Indeed, where they’re still government owned, there’s a good case for releasing it in the spirit of Government 2.0. Google or an enthusiastic amateur would probably jump at the chance to integrate the data into google maps. The service would then be even cheaper.

And frustrated commuters…well, their buses are still late, but they won’t feel as impotent. The benefits are certainly worth the modest costs.

About Richard Tsukamasa Green

Richard Tsukamasa Green is an economist. Public employment means he can't post on policy much anymore. Also found at @RHTGreen on twitter.
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19 Responses to Buses, queueing theory and smart phones

  1. JJ says:

    I always thought it was that at least trams and trains had tracks so there should be less ability to simply disappear!

  2. James A says:

    I was in Melbourne, and the Tram Tracker app looked incredibly useful.

    Transperth is looking at acquiring a realtime bus information system.

  3. Ian Bright says:

    This is already in operartion in many bus stops in London. It was introduced in the past few years. Sign boards show buses due, their route number and how many minutes before arrival. It works fairly well but is not at all bus stops.

  4. heathG says:

    The T80 express bus route from Parramatta to Liverpool has bus stops that include an electronic indicator board to give you an indication of when the next bus (and following bus) are expected.

  5. Dave says:


    Great idea. But how about signalling the demand side as well? If, when arriving at a bus-stop, a smart-phone owner signalled (somehow) that he was waiting for a bus, the transport authority would have a better idea of how many people were waiting and for how long, enabling them to better plan their routes.

    OK, this idea might need a bit of work. Non-phone-owners would be disenfranchised and phone-owners may either ignore or game the system. But it would seem to have some potential.

  6. MsLaurie says:

    Perhaps some sort of ‘call button’ at stops (at least major ones)?

  7. Caroline says:

    A “call button” could work like buttons at the station and tell you where the next bus is, and what the traffic is like.

    I’m in Melb and my bus route has each stop numbered with ID and something in braillle, perhaps the number? If these were installed (months ago) in anticipation of a BusTracker system, then they haven’t told the call centre. While waiting a long time for a bus (2 buses should have arrived in the time we stood at stop) I called the info line and told them my stop number. The person I spoke to had no idea what I was talking anout.

  8. Richard Green says:

    Dave – This is quite a fascinating idea. Whilst transport authorities always have had the ability to use ticket sales to assess patronage, I would like to see how they react to waiting data. It’d be fascinating to see how the rhythms of workplaces and schools and other aspects of life are out of kilter with transport timetables by a few minutes here and there….or even how those rhythms adapt to transport timetables.

  9. I used the Melbourne system twice before giving up – though it is supposed to give you real time estimates and even type of tram (relevant for the disabled on routes using a mix of low and high floor trams) it was hopelessly wrong on both occasions.

    Admittedly the prompt for using it was that scheduled services had not arrived and something was clearly wrong and it may be better for routine operations.

    The Myki system is also hopeless.

    Victoria has tried but failed to use IT to improve public transport.

  10. Matt C says:

    I’ve found the TramTracker app really reliable and useful. The problem is that it makes the lack of real-time updates for buses all the more frustrating!

  11. Matt C says:

    Also as a recently-defected West Australian, the whole Myki debacle perplexes me. WA managed to bring in its SmartRider system (basically the same thing) at a fraction of the cost, in a fraction of the time, with a fraction of the glitches. Why has Myki been so problematic??

  12. BruceT says:

    I agree that wait-time information is enormously helpful. In addition to making the time feel less painful, it allows you to take a less convenient service if your preferred service is running late.

    I haven’t used the Melbourne one, but these systems are fantastic elsewhere. This one in San Francisco is driven by GPS and is 100% accurate in my experience. (Watch those little buses move around the map in real time!)


    The only enhancement that might be good would be something telling you how full the buses are, but that would probably be difficult to implement.

  13. Richard Green says:

    Bruce T – This is almost exactly what existed in my mind’s eye. I knew it was possible, but I guessed inertia probably would have stopped it being implemented. Awesome!

    Matt – I knew your lack of all encompassing resentment towards the Eastern States meant you were just a phoney Westralian.

  14. BruceT says:

    I should clarify that the above system is accurate in the current location of the buses, but obviously not 100% accurate on the estimated arrival time due to street traffic, loading time, etc.

  15. Tel says:

    From the Auditor-General’s Report to Parliament 2009 Volume Ten:

    On-time running performance is measured as the percentage of monitored buses departing from the terminus within five minutes of the scheduled timetable. A minimum of one per cent of total bus trips are monitored. On-time running performance for Sydney Buses has remained relatively stable over the last five years.

    In determining this performance measure, State Transit is working with the Roads and Traffic Authority to implement the Public Transport Information and Priority System (PTIPS) on all buses, which uses GPS technology to provide real time tracking of buses. This tracking will allow the Authority to measure the on-time running performance of all its bus services at all points of the journey. The system can provide priority through traffic lights to help keep bus services to timetable. The Authority is progressively fitting all State Transit buses with PTIPS and as at November 2009, only 62 units were yet to be fitted.

    The Authority has various strategies to maintain and improve on time running. These include the expansion of prepay services to minimise boarding times and the trial of three door buses to facilitate quicker unloading times. The Authority is also consulting with the Roads and Traffic Authority regarding the extension of the bus lanes and their hours of operations and the introduction of clearways on busy corridors.

    If you search on PTIPS and SCATS you can find a bit more about them. It’s rather difficult to find any budget breakdowns on how much these systems actually cost (SCATS has been under steady development since the 70’s), and to the best of my knowledge neither PTIPS nor SCATS releases any data for public consumption (the failure of the whole 2.0 concept is that no government enjoys releasing data that might give citizens a toehold toward performance evaluation). The RTA does let you watch some of the traffic cameras to see how congested various roads are at the moment.

    The SCATS systems is supposedly highly advanced delivering optimal phasing of traffic lights, but I’ve seen a number of situations where phasing is so bad it almost deliberately makes certain routes unusable (e.g. going South on Harris Street, Ultimo past Broadway has been timed to perfectly trap traffic on every cycle). I’m not the only one who has noticed phasing being used as an apparently deliberate anti-private-vehicle measure.


    The RTA are a bit sensitive about releasing either data or strategy explanation when it comes to traffic light timing, so don’t expect much cooperation in the near future.

  16. BruceT says:

    The RTA are a bit sensitive about releasing either data or strategy explanation when it comes to traffic light timing

    The NSW state government seems to be sensitive about all their transport data. I was working on a web application to try to create a better Trip Planner site, and asked the Transport Data Centre if they were able to provide the GIS location of bus stops. The response was “I’m afraid that we’re only able to provide this data for specified projects and there is a fee for it.”

    What are the odds that the fees earned licensing bus stop locations (my guess: $0 in annual revenue) generate more benefits for the people of NSW than making information such as this freely available? People developing mobile phone apps (real developers, not hobbyists like myself who give up!), researchers, etc. are far more likely to do something useful with the data.

  17. James Farrell says:

    ‘you can watch it crawling towards you’

    That could be even more exasperating, in some places where ‘crawling’ is an exaggeration.

    heath G’s solution sounds like the ideal one. What you really want to know is how long you’ll have to wait, not where the bus is.

    Since he mentioned the T-way, I’ll make a comment that I was going to write on the Metrobus thread in answer to Derrida Derider’s excessively emphatic dismissal of your argument: Western Sydney has the T-way on numerous arterial routes, and it works well on most of them. Where it fails is where there isn’t room for a dedicated bus lane. The worst example I know is Windsor Road, the main artery from Parramatta to Baulkham Hills, Castle Hill, Kellyville and numerous suburbs beyond. Nothing short of metro rail will alleviate this problem. Please permit me to go on dreaming about this, because when it finally happens life will improve dramatically for a couple of hundred thousand people.

  18. Richard Green says:

    There’s nothing wrong with the dream of a better solution, so long as it isn’t cherished in a way that condemns partial and minor solutions. So long as we don’t starve ourselves spurning the hamburger because we’re not getting the steak we quite rightly deserve.

  19. Dave says:

    “‘you can watch it crawling towards you’

    That could be even more exasperating, in some places where ‘crawling’ is an exaggeration.”

    If the traffic is really bad, you may have the option of walking to the next stop and catching the bus that you just missed!

    That would be far from exasperating.

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