Population versus Vehicle Travel

Prompted by Brendon Harre, I had a look at the population of each region in New Zealand compared to the amount of vehicle travel it has each year (“vehicle-kilometres travelled” or VKT).

I took the populations from Statistics NZ, both the 2018 counts and the 2048 future projected population.

I then took the vehicle-kilometres travelled from Ministry of Transport Data.

If you graph the 2018 data together, you get this. The blue bars show population (left-hand axis, and the orange dots show the vehicle-kilometres travelled (right-hand axis).

You can see that, for most regions, the orange dot sits about the same height as the blue bar. For example Northland has just under 200,000 people, and every year has just under 2 billion kilometres driven (about 10,000km per person).

Auckland and Wellington both have orange dots sitting below the blue bar, meaning there is less vehicle travel than you’d expect in those places.

Waikato and Canterbury both have orange dots sitting above the blue bars, meaning there is more vehicle travel than you’d expect in those places.

You could posit a few different explanations for these exceptions. It’s quite interesting that the four most populous regions of New Zealand are all outliers to the norm. And of those, the two that have passenger rail are low outliers (Auckland and Wellington), while the two that don’t are high outliers (Canterbury and Waikato).

I also did the same graph but with the future 2048 population projections added in (green bars).

This highlights the enormity of the growth expected in Auckland. It does seem fair that so much of our transport funding is being directed there.

The next highest growth is Canterbury, followed closely by Waikato. Improving transport alternatives in these regions should be high priority as well, especially given that they have higher than average vehicle travel at the moment.

Wellington and Bay of Plenty round out the five biggest growth regions, with both regions already having lower than average vehicle travel.

<UPDATE>

Have created the third graph below, which is the same as the second one except:

  • Orange dots represent light vehicle ownership per capita, rather than vehicle-kilometres travelled.
  • Have just looked at the four largest regions after Auckland, as that’s what I’m most interested in.

Of the four most populous regions in New Zealand after Auckland, Canterbury is the largest and will continue to be so. It also has the highest light vehicle ownership rate.

Wellington is currently the next biggest, but has relatively low growth forecast, with Waikato overtaking it by 2048. Wellington has the lowest light vehicle ownership rate, while Waikato is higher.

Bay of Plenty has higher light vehicle ownership rate than Wellington and Waikato, but is still lower than Canterbury, and has significantly lower population than the other three regions.

Canterbury has the highest light vehicle ownership rate of these four areas. This is, at least in part, a reflection of its poor public transport provision. This should be of national concern, given Christchurch is forecast to be New Zealand’s second largest growth area over the next 30 years.

10 thoughts on “Population versus Vehicle Travel

  1. I wonder if a third graph showing (1) regional population increase (2018 to 2048) for the five most populous regions, (2) population in 2018 and the projected for 2048 population (but drop Auckland because that distorts the scale and makes comparison between the other regions difficult) and (3) light vehicle per capita ownership (2019).
    The light vehicle data being
    Auckland 0.76
    Canterbury 0.94
    Wellington 0.68
    Waikato 0.79
    Bay of Plenty 0.88
    That would show by 2048 Waikato overtaking the Wellington region population wise.
    And the two low outliers for light vehicle ownership being the two regions with commuter train networks.
    These facts reinforces the logic of the government investing in rail for Waikato with the start of Te Huia – which is part of a wider Waikato/Auckland and Waikato regional strategic rail plan.
    Canterbury/ Christchurch given is now the sole outlier of NZ’s biggest 4 cities/regions without a strategic rail plan.

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    1. Oops bad grammar. Final sentence should read. Canterbury/ Christchurch is now the sole outlier of NZ’s four biggest cities/regions without a strategic rail plan.

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  2. Seems like calculating the per capita kms travelled would be a better way to present this (or at least show it next to the first graph). I would suspect that Gisbourne, West Coast and Southland are also outliers, but just can’t be seen on the graph because of the low base.

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    1. Yea I did think that after I wrote it. I should probably list this out separately so you can see the smaller regions and reword that sentence. But then to be honest it’s only the bigger regions that I’m interested in.

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  3. 72 likes Chris! What a good post.

    Liked by 1 person

  4. The implications of this article are huge, when you factor in climate change commitments and future planned transport capital projects.

    Liked by 1 person

  5. “This should be of national concern, given Christchurch is forecast to be New Zealand’s second largest growth area over the next 30 years.”

    Then it needs an integrated landuse plan (TOD), & appropriate transport pricing to get there (private travel remains heavily subsidised with externalities not being internalised).

    The NPS on urban development provides a short term mechanism ahead of the RMA reforms.

    One hopes the climate change legislation will also require full weight to be given to CO2 in land use decisions.

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