Auckland's 2016 Unitary Plan upzoned approximately three-quarters of the city's residential land, permitting medium and high-density housing where previously only detached houses were allowed. The effect on construction was immediate. Research from the University of Auckland found that around 22,000 new homes consented between 2016 and 2021 were a direct result of the upzoning — one third of all homes consented in residential areas, equivalent to 50% more dwellings than would otherwise have been built.

By February 2024, Auckland's housing stock had grown by around 80,000 units — a 15% increase — since the plan became operative. The population aged 20 to 34 grew most strongly in the most upzoned areas, suggesting young people disproportionately benefited.

The rent effect was clear. Between 2017 and 2024, rents in Auckland rose 22%, compared to 34% nationally and 36% in Wellington. Research by Greenaway-McGrevy and So estimates rents are now 28% lower than they would have been without the reform — equivalent to hundreds of dollars per month for the average Auckland renter.

Auckland housing is still expensive, and the researchers are clear that upzoning is not a silver bullet. The ratio of adults to dwellings remains higher than it was in 2000 — more building is still needed. But the evidence is unambiguous: the reform produced more homes, more homes produced slower rent growth, and the cities that did not reform saw faster rises.

Lower Hutt is the most important case study in the global evidence base, because it acted alone. Auckland's reform was city-wide and nationally coordinated. Lower Hutt — a city of 114,000 people in the Wellington metropolitan area — implemented its own sequence of zoning changes from 2016 onwards, without waiting for national reform or neighbouring councils.

The changes included reducing then abolishing parking minimums, targeted medium-density upzoning in central areas, and a later blanket high- and medium-density upzoning across 80% of residential land. Hutt City Council removed parking minimums entirely in September 2020, well ahead of the national deadline.

The results, published in the Journal of Housing Economics, are striking. Housing starts nearly tripled. Around 3,000 additional housing units were generated — 61.8% of total permits — that would not have been built without the zoning changes. Rents fell 21% relative to comparable cities that did not reform. The region-wide housing stock increased by 10 to 18%.

Lower Hutt demonstrates something that matters directly for Glasgow: you do not need national reform to act. A single council, willing to change its own planning rules, can produce measurable results. The evidence is peer-reviewed and published. The only ingredient Lower Hutt had that Glasgow currently lacks is political will.

Minneapolis in 2018 adopted Minneapolis 2040, eliminating single-family zoning across the city — the first major US city to do so. But the headline reform was not the main driver of results. The more important changes were the elimination of parking minimums (phased out from 2009 and fully abolished by 2021) and automatic administrative approval for apartment buildings near transit or in commercial corridors. These unlocked a wave of multifamily construction that the duplex and triplex rezoning alone would not have produced.

Pew Charitable Trusts analysis found that from 2017 to 2022, Minneapolis increased its housing stock by 12%, while rents rose just 1%. The rest of Minnesota saw a 14% rent increase over the same period. Minneapolis had the slowest rent growth rate among the country's major growing cities.

The Federal Reserve Bank of Minneapolis confirmed the city added over 18,000 new units in multifamily buildings from 2018 to 2022 — more than any five-year period in recent history. Homelessness in Minneapolis declined over the same period, against a statewide trend of rising homelessness.

The lesson for Glasgow is not simply "end single-family zoning." It is that parking reform, streamlined permitting near transit, and predictable approval processes together produced results. Each of those reforms maps directly onto what Glasgow should be doing.

Austin's housing story is the most dramatic in the current evidence base. From 2010 to 2019, rents rose 93% — more than any other major US city. In response, Austin reformed its zoning codes from 2015: allowing large apartment buildings near employment hubs, dramatically expanding accessory dwelling unit eligibility, and in 2023 becoming the largest US city to eliminate parking requirements for nearly every property type.

From 2015 to 2024, the city added approximately 120,000 new homes — a 30% increase in housing stock, far exceeding the national growth rate of 9%. Between 2021 and 2023, Austin permitted 957 apartments per 100,000 residents, more than any other major US metro.

The rent effect was immediate and sustained. By January 2026, Austin's median rent had fallen to $1,296 — 4% below the US national median, having been 15% above it in December 2021. Rents in apartment buildings with 50 or more units fell 7% from 2023 to 2024 — the steepest decline recorded in any large US metro. In older, non-luxury Class C buildings — those housing lower-income renters — rents fell 11%. From 2021 to 2026, median rent fell more than 16%.

This happened as the city population continued to grow. The National Multifamily Housing Council concluded: "Austin is not an exception to the rule; Austin is the rule." Supply was the variable that changed. Everything else followed.