This is the second post in an ongoing series on the politics and economic of zoning reform. The first part looked at the costs, benefits, and distributional impacts of reforming urban planning rules to enable more development. This part takes a more specific look at the most recent reform to Auckland’s planning system: the Unitary Plan.
Now that the hearings are over, the submitters have been heard, and the politicians have voted, it’s worth asking: What have we gotten from the Unitary Plan? Does it take us in a useful direction, and to what degree?
In order to give a coherent answer to this question, I’m going to have to simplify matters. The UP does a lot to regulate development and local environmental issues – addressing everything from air quality to zoning for factors. But it has the strongest effects are on the city’s housing market. The UP shapes how much housing can be built, where it can be built, and how easy it is to get permission to build it.
Consequently, I’m going to focus on the impact of the Unitary Plan on people’s ability to build more homes in the city. Zoning capacity isn’t the only thing that matters, but it’s important. Cities that have “downzoned” severely, like Los Angeles in the 1970s and 80s, typically experience rising housing prices, while cities that “upzone” significantly, like Tokyo in the 1990s, tend to have an easier time keeping prices under control.
In order to estimate the UP’s impact on Auckland’s capacity to build more homes, I’m going to draw upon “capacity for growth” modelling produced by Auckland Council and subsequently updated throughout the hearings process. As changes to the modelling methodology make a like-for-like comparison a bit difficult, I’m going to have to piece together the overall results.
The 2012 Capacity for Growth Study estimated the number of homes that could be built under the legacy zoning rules that were put in place prior to Auckland Council amalgamation. The modellers estimated a measure of “plan-enabled capacity” – i.e. the total quantity of housing that could be built within the city if everyone (re)developed their site to the maximum permitted under the zoning rules.
This is obviously an implausible scenario, as many people won’t choose to redevelop, at least for a while. So the results are best thought of as a theoretical upper bound rather than a realistic estimate of what would happen in practice. As we’ll see, this was addressed in subsequent modelling undertaken during the hearings.
With that caveat in mind, the modellers found that the legacy zoning rules allowed between 250,000 and 345,000 additional dwellings to be built in Auckland. The lower number reflects the maximum capacity for infill development, while the higher number reflects the maximum capacity for redeveloping residential sites.
The 2013 Capacity for Growth Study used the same methodology to assess the version of the UP that was notified by Auckland Council after consultation on the plan. This showed that the notified UP had only made incremental increases to infill and redevelopment capacity within the city.
The modellers found that the legacy zoning rules allowed between 258,000 and 417,000 additional dwellings to be built in Auckland. The lower number reflects infill capacity, while the higher figure reflects redevelopment capacity. However, it also noted future greenfield areas with capacity for around 90,000 additional dwellings.
Taking the greenfield areas into account, the notified UP would have delivered a 39-47% increase in capacity for housing, relative to the legacy zoning. That difference is shown in the following diagram. Essentially, the Unitary Plan as originally conceived would have been at most an incremental improvement.
Things get a bit more complex when comparing between the notified UP and the final version of the UP that was recommended by the Independent Hearings Panel and approved (with minor tweaks) by Auckland Council. The modelling methodology changed in the course of the hearings, with the focus shifting from “plan-enabled” capacity to “commercially feasible” capacity. In effect, a new model was built to filter out sites that wouldn’t be profitable to develop.
The result was the final numbers presented in the Independent Hearings Panel’s report (and covered, somewhat hyperbolically, by the Spinoff) are lower – but considerably more realistic – than the figures reported in the Capacity for Growth Studies.
You can see that in the following chart. The commercially feasible capacity enabled by the notified UP is 213,000 additional dwellings – only 42% of the full plan-enabled capacity.
The key thing in this chart is the change between the notified UP and the final UP. Feasible capacity has increased from 213,000 to 422,000 dwellings, or a 98% increase. Most of the increase in capacity comes from within existing residential zones, thanks to rezoning and changes to zoning rules to allow people to build more dwellings on the same amount of land.
So if we squint a bit, we can put these estimates together to get a rough picture of the overall outcome:
- The notified UP increased plan-enabled capacity by 39-47% relative to the legacy plans
- The final UP increased feasible capacity by 98% relative to the notified UP
- This implies that the final UP has increased the zoning envelope by around 175-190%, relative to the legacy plans (i.e. 1.98*1.39 to 1.98*1.47).
Equivalently, if we assume that only around 42% of the plan-enabled capacity under the legacy zoning plans would be commercially feasible (a similar ratio to the notified UP), we can put together the following chart:
Is this sufficient? Time will tell. Getting housing, transport, and place-making right for Auckland doesn’t end with a planning rulebook. But the final UP is undoubtedly a large step away from the broken status quo.
As this is a series on the economics and politics of zoning reform, I want to close with a few simple observations that arise from the quantitative analysis in this post.
- The incremental changes observed between the legacy plans and the notified UP reflect the outcome of a political process. Council put out a draft plan for consultation, and then pulled back a lot of the changes in response to criticism.
- The considerably larger changes between the notified UP and the final UP arose from a technical process – the independent hearings.
- Although the IHP recommended, councillors decided. The final UP was voted up by many of the same councillors who had pulled back to a more conservative position three years before.
This in turn raises two questions that I will revisit in future posts in this series. First, why did the political process deliver a more conservative outcome than the technical process? And second, what changed between 2013 and 2016 to obtain a different outcome from the council votes on the plan?
What do you make of these figures?