Housing density determines transport provision.
I think this needs to be talked about more in Christchurch. This article uses Census data to confirm that this is the case in Canterbury, then uses pictures to discuss how this plays out for different types of housing we have in Christchurch.
The 2018 Census asked people what type of dwelling they lived in, and how many motor vehicles they own.
For an unknown reason Statistics NZ have never published the raw results to Question 2 – I’ve requested this but they don’t seem able to provide it. So I’ve used the responses to Question 3 instead.
The graph below shows areas of Canterbury graphed by the percentage of joint dwellings along the X-axis, and average cars per household along the Y-axis.
It shows that areas with mostly standalone housing (which is most of Canterbury) tend to have high car ownership rates (1.5-2.5), while areas with more joint housing (central city, Riccarton, Addington etc.) tend to have fewer cars per household (0.5-1.5). It’s what you’d intuitively expect, but always nice to see the data confirming it.
The next graph is similar, but shows the percentage of people who usually drive to work on the Y-axis.
Similarly, it shows that areas with more joint dwellings tend to have a lower percentage of people who usually drive to work, with more people walking, cycling and taking public transport instead.
Why is this? I’ve assembled some pictures of what these housing types look like in Christchurch, with some discussion on what sorts of transport infrastructure you need to service it.
Lowest Density – Rural / Semi-Rural
This sort of housing can only really be serviced by car. It’s too low density to economically support public transport, and even footpaths often aren’t provided on roads servicing this sort of stuff. My colleague lives on one of these and loves certain aspects of it, but says he does hate that he can’t safely leave the property on foot or bike (he calls it his life-sentence block).
Suburban Standalone Housing
Suburban housing is typically high enough density to support footpaths, but it still can’t usually justify public transport, other than maybe a meandering, low-frequency bus service that isn’t particularly useful to anyone. More trips will be made on foot and cycle, but still the majority of trips will probably be made in a car.
Terraced Housing/ Townhouses/ Sausage Flats
This sort of housing represents a tipping point. We’re now getting into the sorts of densities which are high enough to support buses that are frequent enough to actually be useful. More people in the area means that just about every home will be within easy walking distance of a school, park, shops etc. A lot of these people will still own cars, but they’ll probably be used more as a backup option, rather than being the go-to for every trip.
Low-Rise Blocks of Flats
This sort of density means there will be loads of activities within an easy walk – both these pictures are in the central city within a few minutes walk from tens of thousands of jobs, thousands of restaurants, cafes, bars, shops, schools, polytech, sports stadia, concert venues, etc. Every street will have footpaths and there’s even enough people to support pedestrianised lanes and plazas. It’s also dense enough to support excellent public transport – both these examples are serviced by multiple bus routes going all over the city, every few minutes, all day long. Some of these sorts of buildings offer carparks to residents, but a lot don’t – relatively few trips need to be made in cars from this type of development.
Higher-Rise Apartment Blocks
This is the highest density housing in Christchurch. We don’t have a lot of it, and the stuff we do have is all in the central city, with plenty of attractions easily walkable, and excellent public transport.
Here’s the national proportions of the housing types.
You can see that the vast majority of New Zealanders live in standalone houses, with a reasonable chunk living in low-rise joined dwellings, and very few living in anything else.
Housing density determines transport quality. If we want a city that is easier to walk and bike around and has better public transport, by far the most important thing we need to do is increase density. This means shifting from standalone houses to the other typologies in as much of the city as we can. And the further down the list we can get, then the better transport outcomes we’ll have.