Last year I started to take a look at demand for new transport investments. I found that demand for toll roads has massively underperformed, showing that people are unwilling to pay for new roads. On the other hand, demand for new public transport facilities has taken off more rapidly than projected. All alternative modes are growing rapidly in Auckland, while driving has stayed flat for the past decade.

Why won’t it grow? We thought it would grow!

The conundrum is, basically: Why is this happening? I argued that declining willingness to pay for new roads is consistent with a saturated market – i.e. all the people who value driving are already on the road. But that doesn’t explain why demand for public transport, walking, and cycling has been so robust over the past decade.

Here, I want to investigate a potential reason for the boom in demand for Auckland’s “missing modes”: the “complete network” effect. I discussed this briefly in a post on the benefits of cycle investments:

Importantly, the researchers found that a larger, more ambitious programme of cycle upgrades will deliver a higher benefit-cost ratio than a smaller programme. This is what economists sometimes call the “complete network” effect – in effect, the more places you can get to easily and safely on a bicycle, the more likely you will be to cycle. (This is also why Facebook has so many users: You have to have an account because everybody else also has an account!)

Here, I want to take a deeper look at demand for relatively new, expanding networks. A 2008 working paper by Arthur Grimes (“The role of infrastructure in developing New Zealand’s economy”, pdf“) provided some historical data on how demand evolved for two important 19th-century infrastructure networks: telegraphs and railways. Grimes suggests that growth in demand on these networks followed an “S-shaped pattern” of rapid initial growth, a period of modest growth, and then a second period of rapid growth after the network reached a certain size:

A forecaster in 1866 would have had little ability to judge the extent of use of the new infrastructure over subsequent years given the lack of precedent for it. A forecaster in 1896, having seen 15 years of constant messages per person may confidently have forecast a stable outlook for that variable over the coming decade. He would have been mistaken almost by a factor of two within ten years.

Grimes’ data is summarised in the following graphs, with telegraphs on the left and railways on the right. The bottom two graphs show the “S-curve” in per-capita demand clearly:

Grimes (2008) infrastructure uptake curve
Source: Grimes (2008)

This nonlinear pattern in demand is likely to reflect two factors. First, growth in demand is fast at first because infrastructure builders start by constructing the best projects – i.e. the ones that will attract the most customers quickest. Once these projects are built, the next ones attract demand more slowly – roughly at the rate of population growth.

Second, the later upturn in the curve occurs after the network reaches a sufficient “critical mass” to become increasingly useful for more purposes. This is the complete network effect in action: filling in the missing links in a network can enable it to serve many more trips (or messages).

I would argue that demand for Auckland’s “missing modes” is following a similar trend. So: Where are we on the “S-curve”?

First, we cannot expect an uptick in demand after the construction of Waterview finishes off Auckland’s motorway network. While Waterview is a sensible stopping place for expansions of Auckland’s motorway network, it is at best a marginal improvement in the city’s road networks. There are already a number of roads that connect the north and northwest to the south.

Second, in public transport, I would argue that we are probably on the tipping point to sustained rapid growth:

  • We’ve got an existing bus network which supports steady if not spectacular growth in demand. Auckland Transport is currently in the process of reorganising it into a New Network that provides more frequent all-day services that serve many more destinations than before. This could easily lead to a boom in bus trips.
  • We have an existing rail network that has experienced a revival in demand since the development of Britomart in 2003. The City Rail Link will transform the usefulness of the rail network by breaking out the bottleneck in the city centre and enabling a doubling in train frequencies.
  • New rapid transit infrastructure can capture significant new demand when it’s made available – as the Northern Busway has done.
Improving rail networks can experience big jumps in demand.

Third, the cycling network is probably a few steps behind in the process. There’s likely to be a period of steady if not spectacular growth in demand as new projects come online, but under NZTA and AT’s current investment plans there will be gaps in the network for a number of years. At a certain point, though, the gaps between safe cycle infrastructure will be filled in, enabling rapid growth in demand as cycling becomes safe and useful for many more trips.

When cycling seems safe and easy, lots of people cycle.
When cycling seems safe and easy, lots of people cycle (Source)

In short, the “S-shaped pattern” of uptake for new transport networks will shape demand within New Zealand’s cities following new investments in public transport, walking and cycling, just as it has done on previous infrastructure networks. The only question is: Are we willing to invest in our “missing modes” to make them increasingly useful for more and more trips?

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  1. Cycling investment is at a good beginning place. As demonstrated by the photo, one of the main reasons it’s smart is because the narrow bicycle’s single width is an efficient use of road width. In other words, bicycling, walking, in-line strolling, scooting, seguaying, motorcycling = good. Cars with passenger sides driven by single occupants = far less efficient use of road width.

    This obvious key attribute is the main factor in determining its effectiveness. The willingness to invest in it depends on its perceived ability to transport people safely, quickly, and pleasantly. The same applies to an even more overlooked mode of transport; the building of single-width highway capable cars and lanes.

  2. Peter I fully agree with you. I think the 18% growth in rail shows there is bent up demand for alternative networks. So how do we get bus and cycle up from below a 1 star service. Primarily we give them max possible width and signal priority on the main roads. Cycle made safe all round, bus made frequent ideally rapid and cheaper than now. Both these networks work with rail to get a mode change of at least a 1 in 3 from using a car and then even cars are flowing, therefore even trucks are flowing. For what removing parking and flush medians on main roads, a main roads remark and signal works. Reducing fares coupled with a $10 carpark charge for starters and see how that works. I won’t double up but in more detail under year ahead in 2015. The mayor and the transport head just need to say do it.

  3. “all the people who value driving are already on the road” Plus how many of us (in Auckland especially) drive because we value it but because there is no choice?

    1. For investing in some white symbols and white lines we will soon find out. As opposed to spending billions adding to a one mode network and never knowing. For a quick mode share rebalancing you can cycle, bus, and drive in free flow for a change. Thats it create an extra 2 viable choices for a paint job, not closing them out and suffering the consequences.

      1. The remarking is just white lines and white painted symbols every 50m. Green surfacing is a wasted opex cost at each reseal and not needed. Initially for the first 3 months blacked out obsolete lines will do, cheaper and gives time to confirm layout before blasting these off. Signal team changing priority of signals, adding bus and cycle priority signals, advance detector loops for alerting signal of approaching bus or cycle.

        1. Opening up the bus and cycle network is easy and within road maint, no capex except on signal hardware. Do we have the mandate, and do we have the buses, more cycles well 50% off at bike barn right now. After mandate approved it is just looking at each main road and maximising those two modes with thought for additional cycle room for physical protection. Car we won’t cut you off completely but you will be carrying less fat so you can actually run again.

          1. Peter interesting about ” full network effect”. That is why full cycle let’s do it. Bus full network let’s do it. What is the opportunity cost of not having these networks up. Fully believe 1000 buses with priority firing citizens at rail and/or a rapid equivalent elsewhere will take 30% fast. Congestion gone. Then you have cycle rising up to a possible 36% but even if you said 10% in 6 months and growing then you add physical protection full network as soon as possible. $1.25b pet annum in congestion gone, truck,car free flow.Bus up to 4 star, Rail 4 star, Cycle 4 star, opportunities for more pedestrisnised areas, better links to ferries. This should be an easy sell but we are not used to this we are trying to get car from 2 star but you will never get the width in a city no matter how many billions you try and throw it without these other modes doing their thing and taking the bulk.

  4. Vancouver’s rail network is similar in size to Auckland’s and carries 140m trips a year. We just need better integration with land use, bus services and cycling. Plus way more frequent services.

    So much growth potential. Which is good given the very high marginal cost of providing additional roading capacity.

  5. The key for cycling growth will be grade and separation. It will grow up until a point, but from then on it has to be more than safe, it has to appear safe.

    I can see city cars having a future, but not tiny SOV boxes with minimal crash protection. Gordon Murray’s 3 seater is more of an indication where we may end up. It would free up additional parking spaces from our existing parking stock and reduce the footprint of commuter traffic while still being practical enough to replace a household vehicle, not be merely an addition to a garage just for commuting.

    1. Not all highway-capable narrow cars have minimum protection. For instance, the A-Car proposed by Auckland’s Microcar Project has a roll cage and four steel bars in each door. Therefore, it has far more protection than a standard car’s driver side door, bicycle, motorcycle, scooter, or walking and still maintains the attribute that makes bicycles and protected bike lanes a promising “missing” mode of transportation as evidenced by the photo in this post.

      1. I’m not sure the SOV is the way to go, but at least it’s a fully enclosed microcar and not a doorless motorbike with a roof 😛 . I’m still more of a fan of Murray’s three seat design though.

  6. That graph with all the multicoloured failed “predictions” looks to me like a cartoon caricature close-up of the head of a balding stick figure (Pak n Save guy?), with the former failed predictions being whats left of his hair trailing out in the winds of change. I’m sure thats how NZTA, NZIER, MoT and all those other prognosticators feel about the whole “why won’t traffic rise any more” situation they are now (reluctantly) facing.

    That Perth v Auckland graph is getting pretty “last decade” – its now 2015 – we’re halfway through the next decade, (2010-2019) and we have over 12m people on the trains and they’re now partly electrified like Perths was in 1991.

    Any chance of (a) an updated graph with 2012,13 and 14 figures being added, and also (b) a fresh graph that moves Perths passenger figures by 20 years “later” to align Perths 1989 numbers with Aucklands 2011 figures (and which then includes the actual Auckland rail figures from 2012 to (Nov) 2014)? And to help make the years show up individually, not just every odd numbered year – trim the Auckland numbers before 2003 as that aligns with Perths 1981 “start figures”.

    That way the same sparks effect that Perth had should (a) become obvious as happening here too – something we keep getting told by naysayers that will never happen as we’re not at all like Perth.
    and (b) we can use the Perth rate of climb they experienced post 1991 as the visual predictor or where Auckland rail usage is going.
    [If the figures are available, I’m able to fiddle a spreadsheet to have a crack at doing that if you like].

    While Perths experience in the ’90s may be 100% accurate as a exact predictor of Auckland in the ’10s,
    I’m damn sure it will be way, way more accurate over the next few years – than all those traffic predictions of late have been.

  7. We – the taxpayers must be paying big salary monies for our public servants at the Ministry of Transport for forecasting NZ’s most relevant transport requirements. How come they have been getting it wrong for so long?
    And they are being out researched by a bunch of talented amateurs at Transport Blog. It’s bloody marvellous!
    I think Mr.Dangerfield or whatever his name is, should be sacked forthwith and replaced with somebody more capable.

  8. It bears mentioning that if a service is attractive enough, people will use it – no market analysis necessary. I offer the TGV as exhibit A. It was and is such a superior service to driving or flying that it naturally attracts patronage. That wouldn’t be captured in a market study that tends to look at documented usage of existing systems, population projections, etc. There is a huge intangible factor, one which most PT agencies either overlook or discount. But they do so at their peril.

    Those demand curves up above are an indication of this. Maybe everything was in place so that demand *should have* met the projections, but what about the things that couldn’t be known or accounted for?

    1. As Mark Twain, its not the things you don’t know that are the problem, its the things you “know” for sure, that “just ain’t so” that are..

      I fully expect that those traffic predictions have factored in all the knowns, all the known unknowns and all the “only on a Frosty Friday” cases too – hence why they’re so wrong.

      As for TGV selling itself, yes the French (for all we love to hate them with their outrageous self-belief and idiosyncratic nature), do sometimes get it right – they did sell the fact that TGV train trips are generally much faster “door to door” than most flights, between the main centres in France. And that was well before 9/11 and all the crap security checks and check in early to not miss your flight stuff we put up with now.

      The French also put the Paper Phone Directory online in the early 80s and invented online social media along the way with their MiniTel system too – now just a footnote in history.

  9. The obvious thing about those monotonal and failed forecasts is that they just express the stubborn assumption that driving levels must keep going up indefinitely outside of a recession. That’s all they show. The accepted group-think by the transport and economics bureaucracy. Note that some years they are actually quite accurate for the short term, when they presumably have some actual data, like truckers forward bookings, but then they all go back to the pre-2004 angle.

    The question is how long does this assumption have to be shown to be wrong before some deeper thinking gets applied to this issue? 10 years looks well long enough to me. Isn’t flat the new normal now? I would expect forecasts now to bias towards no growth outside of extraordinary information arguing for either growth or decline [big population changes, for example]. Especially as we have had positive economic and population growth over this period and isn’t a decoupling of economic activity and driving quantity exactly what you’d expect to see in an increasingly digital and urbanised world?

    How many trucks on how many RoNS, for example, does it take to get Xero’s product to market?

    And without the massive overbuild of the RoNS how flat would the heavy vehicle index be? Is motorway construction now it’s own justification?

    1. Patrick, these guys are not working in the interests of :
      providing smart transport mode options,
      taxpayer ,
      smart safety options
      the environment or anything sustainable.
      How long before we all see it? Well I hope they at least get their own gas paid for from this corrupt/ one modal focus. It is making us go backwards at $4b per annum when you take fatalities and congestion into account. I think Donald Trump would say your fired 60 years ago when they removed the trams, and other untold damage to every other mode of transport since then. But hang on the new Government Policy Statement will change all that..Nope not even with the billions, motorways, almost all arterials full width and zero growth?

      1. MOT/NZTA are probably calling their bosses at Mobil and BP now. I think these guys are catching on. What do we do, do we keep building motorways or do we have to start building the sustainable things and othet modes clearing congestion. No just keep giving those sustainable modes minimal and set higher patronage targets. But our graph has flat lined and theirs isn’t even with minimal? Look just keep going. East-West brilliant and the reeves rd flyover sublime. We’ll just turn those bus lanes into 2 lanes later and extend eastern motorway to Glen Innes. OK divine masters, at your command.

  10. Interesting. No one has said much about population growth over the last 10 years in relation to transport usuage. I would guess that’s were the people using alternative & public transport are coming from. I understand Aucklands population has grown by 25%-35% and the increase in public transport use is similar. So yes we have the same if not more vehicles on the road & a steep increase in public transport usage. We’re also virtually giving away bus tickets to students while us adults subsidize these fairs. just a thought in this debate

    1. I took a look at this issue in a previous post using journey to work data from the Census. See here:

      Effectively, between the 2006 and 2013 Censuses, the number of workers in Auckland rose 3.5%, while the number of people commuting by PT or active modes experienced double-digit increases. The majority of new commute journeys (61%) were undertaken on alternative modes. And that’s counting only workers, who pay full PT fares.

      Other data confirms that demand for PT is outstripping population growth, while demand for driving is weak. AT’s data suggests that PT boardings are growing at least twice as fast as Auckland’s population. Meanwhile, MoT’s data on driving shows that’s there have been modest but sustained reductions in vehicle kilometres travelled per person in Auckland over the last decade. (See

    2. “We’re also virtually giving away bus tickets to students while us adults subsidize these fairs [sic]”

      Subsidising students PT fares is one of the most cost-effective ways to improve the road network you can do.
      Imagine if every school age kid and university student in Auckland who had mummy drop them off now (or who drove to school) used PT,walking or cycling to get to/from their schools/university – why traffic would be like it is in the school holidays – **every single day of the year**.

      Growth of PT v population:

      VKT in the Auckland Region in absolute terms has absolutely flatlined for 10 years. Who says?
      NZTA says – see this link for the details:

      And for a NZ wide “picture” of the same thing.

      Auckland is responsible for about 29-30% of the total NZ wide VKT, So even though we have a higher percentage of NZ’s population than that – we actually drive less than the rest of NZ does per person..

      Yes Aucklands population is on the up and up, but PT usage is up even more percentage wise than population is – that all means VKT per capita in Auckland is dropping, and PT usage per capita in Auckland is rising.

      So its not just “new arrivals” using PT any more [if it ever was] – there is a sea change underway, the problem is that I think NZTA and their ilk are looking elsewhere and haven’t noticed it yet (or are seeing it but are wilfully blind to it).

      Interestingly enough the Auckland VKT split between “local roads” and State Highways (motorways etc) is around 65%/35%, NZ Average is more like 54%/46% local v State highways, so we use more local roads than state highways compared to the NZ Average – despite having more of State highways and motorways in the region.

      The other point is that NZTA says 77% of the VKT “clocked up” by the NZ fleet each year is from “light vehicles” – mainly private cars. 15% is “light commercial vehicles” (vans. light trucks and the like), and 8% is “Heavy” Trucks, Buses and motorcycles.

      You gotta wonder why we are spending so much of our roading money each year on building expensive motorways – for, we are told, getting all those big freight trucks speeding our goods around the country and also to ports for overseas shipment – when they represent not even 8% of the total VKT.

      Since the majority of VKT in Auckland is clocked up on local roads, it surely makes sense in every way you can think of to put our focus on improving those for everyone (especially PT users) over the big expensive state highways.

  11. Auckland is responsible for about 29-30% of the total NZ wide VKT, So even though we have a higher percentage of NZ’s population than that – we actually drive less than the rest of NZ does per person..
    We may cover fewer Kilometres but we will probably spend longer in our cars to cover them! Especially those in the buses. We really need to get the dedicated bus lanes onto Dominion, Mt Eden, Eastern and North western routes now.

    1. Totally agree. What is wrong with a bus symbol right now. What is that an aluminum template and a white spray can. Crikey get the buses ready and I’ll do it myself.

  12. THis is the weather for everyone to be on their bikes, how can we encourage that especially the commute traffic. I loved the post on the bicycle parking in Tokyo. Seems like a dream solution. I wonder if they have sold the idea in Europe, those ccycle stacks at the trains stations there look like a nightmare.

  13. demand for public transport whatever form is dependent on a number of factors. This as the consumer compares the public transport with other forms of transport. these factors include but are not limited too, cost, convenience, availability, time saving and stress reduction.

    some people can never take public transport, for example an employee that has a company car and uses it during working hours.

    some factors drive consumers towards public transport, e.g. traffic congestion, and cost of vehicles.

    public transport only takes off in a city when the offering to the public has the right mix

    Auckland will always struggle to get the right mix, as it is a de-centralized city with a low population. Cities with distinct center (s) and high populations e.g. Singapore will always have successful public transport systems e.g. MRT

    To make public transport systems successful Auckland needs to make them attractive as possible to general public.

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