Along with keeping a close eye on public transport patronage, I also like track what is happening with traffic volumes. The NZTA release traffic volumes for a handful of sites on the state highway network on a monthly basis and release a much larger number of sites on an annual basis.

We frequently talk about how traffic in general hasn’t really be growing for some time and in the past we have tended to just look at the Harbour Bridge data but with this post I’m expanding it to other sites that are monitored monthly. These are:

  • ALPURT (Orewa to Silverdale)
  • The Harbour Bridge
  • SH1 at Panama Rd
  • SH20 between Puhinui and Massey Rd
  • SH1 at Drury
  • SH1 at Bombay

So what’s happening with traffic volumes?

Auckland Traffic Volumes

With the exception of SH20 volumes are flat and not really doing anything. The reason SH20 is increasing is likely to be primarily due to the recent extensions and upgrades the route has had including the motorway connections at Manukau, the upgrade across the Manukau Harbour and the extension through to Maioro St. I would expect that growth to continue for a while, especially after Waterview is completed. To help show this further the graph below is indexed to when the SH20 numbers first became available in Feb 10 based of the 12 month rolling average. It quite dramatically shows the growth being seen on SH20 and to a lesser extent on ALPURT compared to the other sites on SH1.

Auckland Traffic Volumes Indexed

For the sites on SH1 in particular it is important to remember that this represents a discontinuity with past trends. Here are some of the annual traffic volumes for a few locations around the motorway network which shows just how much the trends have been changing in the last decade or so after previously having reliable growth year on year.

Auckland Traffic Volumes Historic

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  1. More proof of Peak Traffic for which we have been seeing increasing evidence. Of course, this is not evenly spread over the population, with older people driving lightly more while young people are driving a lot less.

    One way to encourage that trend is to continue to take the “sexy” out of driving. This article compares driving to smoking and suggests having warnings on cars, a great idea:

    Maybe we should also have a plain packaging law for cars like cigarettes in Australia, all cars have to be a sickly, hospital green. This has been shown to be the least attractive coliur for human beings. I am joking of course. Probably.

    I actually think that comparing auto dependence to smoking is a little unfair. A much more accurate comparison is to fatty foods. After all, McDonalds once a week is not going to do you any harm, but if you start doing a Super Size Me and having it for every meal, you are facing some terrible health effects.

    So with driving, the point isnt that you wont ever drive, but that you wont assume every trip must be made by car. If most people in Auckland considered any other mode of travel at any time, it would have a huge effect on traffic volumes.

    1. “If most people in Auckland considered any other mode of travel at any time”

      Maybe that’s whats happening right now and hence why our traffic volumes are rather flat on the roads shown above.

    2. The problem is not the cars, the problem is the occupancy in the cars. If we could fill those empty seats the problem would be gone in a minute. Enable and incentivise carpooling. Uber and Lyft have it almost right but it needs to be for the masses, not a slightly-cheaper-taxi. I need to be able to press a button on my phone and get picked up within 5 minutes to get where I’m going with the traffic that is already going my way. It can be incentivised by giving fuel discounts for drivers who take passengers (easily trackable) 20c/litre discount at the pump etc.

  2. It is incomprehensible that given that last chart we have a government, unopposed by our local authority, aggressively building top shelf driving amenity with every cent they can find. The facts do not support this extreme and foolish policy.

    1. The facts have never supported this National Government’s transport policy, which is one reason why I will not vote for them in the next election.

      To think that we’ve had continuing reductions in per capita vehicle travel demands in spite of the persistent subsidies for driving.

  3. Is there similar data collection from elsewhere around NZ? Are the graphs similar and that maybe the higher growth areas like Hamilton, Tauranga/BayCoast & Queesntown for example might be the only areas still showing growth?

  4. Those graphs are pretty stark. For car manufacturers. 10 years of little growth. How is that “just a temporary event” and not a trend that should drive future decisions regarding infrastructure.

    1. Well those are only a select few roads, some roads are growing, others reducing and as seen above others staying somewhat constant.

      If you look at SH16 it’s maintained a constant growth rate since 1995, similar to Northcote to Tristram (where the busway is) and Panama Road.

      If SH18 harbour crossing was up there you would see that it has been growing away rather nicely (vehicle growth is nice) which goes some way to explain why the SH1 harbour crossing has been flat. In addition to that you can clearly see that the traffic volumes on the harbour bridge dived and then flat-lined in 2008 which is the same year the busway opened. It should be noted that when the busway opened a number of other changes were implemented on the Northshore to priorities other bus movements such as along Esmonde, Onewa and East Coast Bays Road.

      Of course the most important thing here is that the historical growth rate has definitely changed between 1995 and 2000.

      If you refer back to the news of the day it was in the late 90s that people were getting up all in arms about the congestion in Auckland and so it was through the 2000’s that projects like the CMJ stage 2 were built along with a new focus on public transport with the most notable aspect being the new Britomart Transport Centre. Given the fact that traffic growth rates reduced at the same time as the existing roads reached capacity and PT systems were improved you would assume that there was a link between this 3 aspects of Auckland transport.

  5. lol, that is precisely what I am trying to convince some designers about in one of the projects I am reviewing. Commuting pedestrians want to go to their destination (aka the desire line) and not take some elaborate path that someone thought looked nice on a plan.

    1. Check out the shared path on the northern side of Highbrook Drive. Talk about not understanding desire lines. Anything you can do to fix these kind of design ideas would be appreciated.

      1. That path is more a recreational path and so people are slightly more willing to take a detour or two provided there is a visual reason why they are deviating and it doesn’t appear contrived.

        However this patch is rather funny.

        It defiantly needs and optional bypass along the line of where you can see people have been walking.

        1. I spent 3 months working out that way last year and the number of people commuting by bike along there was surprising. None were using the path, all were on the road. What if the path had just been built as a real commuting path given the proximity to where people actually might commute to – work?

        2. To be honest I don’t know why they didn’t put cycle lanes on the road through there. That route was clearly made for the purpose of creating a free flowing route to and from East Tamiki so what made them assume cyclists would not want to come along there from Otahuhu I do not know.

  6. I tend to agree. That route (the road) was clearly made with the purpose of commuters traveling to and from East Tamaki so it does seem rather strange that they assumed no cyclists would be traveling along there given that road is one of the few connections to the western side of Auckland.

    I’d suggest on-road cycle lanes would have been the most use through there with that path round the coast just being a 2m wide footpath for weekend walkers and any workers in the area going for a run at lunchtime.

      1. You just need to provide a larger off-set that is all. Or you could a shared use path on the eastern side where the footpath is now which would likely be the easiest and safest thing to do. Getting around the roundabout by the motorway would be rather dangerous however.

        1. Or an on road lane with a median strip and those small plastic bollards to protect them. The corridor is wide enough.

        2. Based on the big book your 1.5m wide cycle lane should have an additional 1m clearance from the traffic lane, so that means you would need to widen the road by 2.5m assuming the existing left hand lane is 3.5m. You can feel free to slap in some posts or whatever in that 1m separation zone but I’d say just some painted chevrons would do.

    1. I fully agree, and if we had the kind of funding that the Dutch do, would be all for it but to be fair the route I was discussing is pretty much a commuter route. Build it on the cheap and fix it properly later if needs be. 80% solutions over as much of Auckland as possible rather than expensive 100% solutions over 10% of the city.

  7. More on the US data showing the trend that is observable across the OECD. Note that the discontinuity precedes the Global Financial Crisis, but is accelerated by it. Also, of the various projections, which is the more sensible to invest for? Any of the extremes? Probably not.

  8. Hmm.

    That second graph showed ALPURT rising quite rapidly as well.
    But that doesn’t seem to me to align with the data in the first graph.

    Sure the data points are right?

    1. That’s just to do with the scale of the first graph. It is rising but of a much lower base than the other roads so it doesn’t look like it is doing anything

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