The City Within Fifteen Minutes

APlanning doctrine in the industrialised world spent a hundred years keeping the parts of a city apart. Homes were placed in one district, offices in another, and workshops at a prudent distance from both, on the assumption that movement between them would remain quick and cheap. That assumption held only while fuel was inexpensive and roads were empty. By 2011 the average one-way journey to work in six large European cities had passed thirty-eight minutes, and the emissions attached to all that travel had become politically awkward to defend. The proposal that followed was arithmetically modest and administratively enormous. A person walking at an unhurried pace covers about a kilometre in a quarter of an hour, and a cyclist roughly four times as far; arrange schools, clinics, grocers, workplaces and parks inside that radius, and the private car ceases to be a requirement of ordinary life. Versions of the argument had circulated among planners since the 1970s without ever acquiring a name, and the label eventually attached to it, the fifteen-minute city, has done more for its adoption than any evidence gathered since.

BThe first serious attempt to test the claim produced an awkward result. Marta Peyró, an urban economist at the Brunner Centre for Settlement Studies, matched travel diaries against the recorded positions of shops and services in 14 districts redesigned along these lines between 2017 and 2022. Proximity itself had unquestionably improved: by the end of the period 78 per cent of residents lived within a fifteen-minute walk of a grocer, against 52 per cent when the work began. Use, however, barely followed. Only 41 per cent of shopping trips ended at the nearest available shop, and the median distance covered on daily errands fell from 3.1 kilometres to 2.8. Peyró maintains that planners have confused what a map permits with what a household actually prefers, since residents will accept a longer trip in exchange for a wider selection, a lower price, or a route that happens to pass the school gate. Her data, it should be said, cover only districts in which a car remained easy to park.

CDevin Achebe of the Fenwick School of Planning accepts these figures and rejects the conclusion drawn from them. The purpose of redesign, he contends, was never to shorten every journey but to make the household car optional, and a family that keeps its old shopping habit while surrendering its second vehicle has delivered most of the promised benefit. He points to the eight districts in Peyró's sample where the work had been accompanied by the removal of on-street parking: car ownership there fell by 12 per cent, whereas in the six districts that kept their parking it did not move at all. Distance travelled, on his account, is a poor proxy for dependence. The distinction matters chiefly for what a city chooses to count, because a programme judged by average trip length will be recorded as a failure even where it has quietly taken a vehicle off the street. Achebe concedes that his own comparison is not experimental, since the districts which removed parking were also those with the most determined local politics, and he allows that the result could belong to the politics rather than to the parking.

DA third objection concerns who is left to enjoy the outcome. Louisa Grandet, a housing researcher at the same school, observes that the districts achieving proximity fastest were also those in which rents climbed most steeply, by 23 per cent between 2016 and 2021 against 9 per cent across the city as a whole. A neighbourhood in which everything lies close at hand becomes, predictably, a neighbourhood that people bid to enter, and the households displaced by that bidding are precisely the ones whose need for a short journey was greatest, since they are the least likely to own a car. Grandet insists that proximity is therefore a good which redistributes itself upwards unless it is built into the rules of tenure from the outset. She is careful, all the same, about how much her figures can carry. Rents rose everywhere during the years she studied, her comparison rests on only six districts, and she does not claim to have separated the effect of redesign from the effect of the investment that usually accompanies it.

EWhat survives of the idea after these three challenges is narrower than the slogan but far from trivial. Where redesign has been paired with a reduction in parking and with some protection of rents, the evidence points to fewer cars and to journeys that residents are at least free to shorten; where it has amounted to little more than a shopfront on every corner, it appears to alter the map without altering the household. The order in which the measures arrive seems to matter more than any of them taken singly, since parking withdrawn before the shops exist produces resentment, while shops added before rents are secured produce departure. Achebe and Peyró now agree on this much, though they continue to disagree about which measurement ought to be reported. Grandet remains the least persuaded of the three. The deeper difficulty is that a planning idea is judged by the photographs it produces, and a street of small shops photographs far better than a schedule of tenancy protections. Until that imbalance is corrected, the label will keep travelling faster than the argument beneath it.