Herman van den Bosch

Urbanisation in the US is undergoing major changes. The image of a central city surrounded by sprawling suburbs therefore needs to be updated. The question is what place does the 15-minute city have in it? That is what this somewhat longer post is about
 
From the 1950s, residents of US cities began moving en masse to the suburbs. A detached house in the green came within reach for the middle and upper classes, and the car made it possible to commute daily to factories and offices. These were initially still located in and around the cities. The government stimulated this development by investing billions in the road network.
From the 1980s, offices also started to move away from the big cities. They moved to attractive locations, often near motorway junctions. Sometimes large shopping and entertainment centres also settled there, and flats were built on a small scale for supporting staff. Garreau called such cities 'edge cities'.
Investors built new suburbs called 'urban villages' in the vicinity of the new office locations, significantly reducing the distance to the offices. This did not reduce congestion on congested highways.
 
However, more and more younger workers had no desire to live in suburbs. The progressive board of Arlington, near Washington DC, took the decision in the 1980s to develop a total of seven walkable, inclusive, attractive and densely built-up cores in circles of up to 800 metres around metro stations. In each was a wide range of employment, flats, shops and other amenities . In the process, the Rosslyn-Balston Corridor emerged and experienced rapid growth. The population of the seven cores now stands at 71,000 out of a total of 136,000 jobs. 36% of all residents use the metro or bus for commuting, which is unprecedentedly high for the US. The Rosslyn-Balston Corridor is a model for many other medium-sized cities in the US, such as New Rochelle near new York.
 
Moreover, to meet the desire to live within walking distance of all daily amenities, there is a strong movement to also regenerate the suburbs themselves. This is done by building new centres in the suburbs and densifying part of the suburbs.
The new centres have a wide range of flats, shopping facilities, restaurants and entertainment centres.  Dublin Bridge Park, 30 minutes from Columbus (Ohio) is one of many examples.
It is a walkable residential and commercial area and an easily accessible centre for residents from the surrounding suburbs. It is located on the site of a former mall.
 
Densification of the suburbs is necessary because of the high demand for (affordable) housing, but also to create sufficient support for the new centres.
Space is plentiful. In the suburbs, there are thousands of (semi-)detached houses that are too large for the mostly older couples who occupy them. An obvious solution is to split the houses, make them energy-positive and turn them into two or three starter homes. There are many examples how this can be done in a way that does not affect the identity of the suburbs (image).
New construction in suburbs
 
This kind of solution is difficult to realise because the municipal authorities concerned are bound by decades-old zoning plans, which prescribe in detail what can be built somewhere. Some of the residents fiercely oppose changing the laws. Especially in California, the NIMBYs (not in my backyard) and the YIMBYs (yes in my backyard) have a stranglehold on each other and housing construction is completely stalled.
 
But even without changing zoning laws, there are incremental changes.  Here and there, for instance, garages, usually intended for two or three cars, are being converted into 'assessor flats' for grandma and grandpa or for children who cannot buy a house of their own.  But garden houses are also being added and souterrains constructed. Along the path of gradualness, this adds thousands of housing units, without causing much fuss.
 
It is also worth noting that small, sometimes sleepy towns seem to be at the beginning of a period of boom.  They are particularly popular with millennials. These towns are eminently 'walkable' , the houses are not expensive and there is a wide range of amenities. The distance to the city is long, but you can work well from home and that is increasingly the pattern. The pandemic and the homeworking it has initiated has greatly increased the popularity of this kind of residential location.
 
All in all, urbanisation in the US can be typified by the creation of giant metropolitan areas, across old municipal boundaries. These areas are a conglomeration of new cities, rivalling the old mostly shrinking and poverty-stricken cities in terms of amenities, and where much of employment is in offices and laboratories. In between are the suburbs, with a growing variety of housing. The aim is to create higher densities around railway stations. Besides the older suburbs, 'urban villages' have emerged in attractive locations. More and more suburbs are getting their own walkable centres, with a wide range of flats and facilities. Green space has been severely restricted by these developments.
 
According to Christopher Leinberger, professor of real estate and urban analysis at George Washington University, there is no doubt that in the US, walkable, attractive cores with a mixed population and a varied housing supply following the example of the Rosslyn-Ballston corridor are the future. In addition, walkable car-free neighbourhoods, with attractive housing and ample amenities are in high demand in the US. Some of the 'urban villages' are developing as such.  The objection is that these are 'walkable islands', rising in an environment that is anything but walkable. So residents always have one or two cars in the car park for when they leave the neighbourhood, as good metro or train connections are scarce. Nor are these kinds of neighbourhoods paragons of a mixed population; rents tend to be well above the already unaffordable average.
 
The answer of the question in the header therefore is: locally and slowly

A previous post made it clear that a 15-minute city ideally consists of a 5-minute walking zone, a 15-minute walking zone, also a 5-minute cycling zone and a the 15-minute cycling zone. These three types of neighbourhoods and districts should be developed in conjunction, with employment accessibility also playing an important role.
 
In the plans for 15-minute cities in many places around the world, these types of zones intertwine, and often it is not even clear which type of zone is meant.  In Paris too, I miss clear choices in this regard.
 
The city of Melbourne aims to give a local lifestyle a dominant place among all residents. Therefore, everyone should live within at most 10 minutes' walking distance to and from all daily amenities.  For this reason, it is referred to as a 20-minute city, whereas in most examples of a 15-minute city, such as Paris, it is only about <strong>the round trip</strong>. The policy in Melbourne has received strong support from the health sector, which highlights the negative effects of traffic and air pollution.
 
In Vancouver, there is talk of a 5-minute city. The idea is for neighbourhoods to become more distinct parts of the city. Each neighbourhood should have several locally owned shops as well as public facilities such as parks, schools, community centres, childcare and libraries. High on the agenda is the push for greater diversity of residents and housing types. Especially in inner-city neighbourhoods, this is accompanied by high densities and high-rise buildings. Confronting this idea with reality yields a pattern of about 120 such geographical units (see map above).
 
Many other cities picked up the idea of the 15-minute city.  Among them: Barcelona, London, Milan, Ottawa, Detroit and Portland. The organisation of world cities C40 (now consisting of 96 cities) elevated the idea to the main policy goal in the post-Covid period.
 
All these cities advocate a reversal of mainstream urbanisation policies. In recent decades, many billions have been invested in building roads with the aim of improving accessibility. This means increasing the distance you can travel in a given time. As a result, facilities were scaled up and concentrated in increasingly distant places. This in turn led to increased congestion that negated improvements in accessibility. The response was further expansion of the road network.  This phenomenon is known as the 'mobility trap' or the Marchetti constant.
 
Instead of increasing accessibility, the 15-minute city aims to expand the number of urban functions you can access within a certain amount of time. This includes employment opportunities. The possibility of working from home has reduced the relevance of the distance between home and workplace. In contrast, the importance of a pleasant living environment has increased. A modified version of the 15-minute city, the 'walkable city' then throws high hopes. That, among other things, is the subject of my next post.

Due to a long stay in the hospital, I was unable to post my columns. I also cannot guarantee their continuity in the near future, but I will do my best... 

In my previous post, I emphasised that urban densification should be coordinated with other claims on space. These are: expanding blue-green infrastructure and the desire to combine living and working. I am also thinking of urban horticulture. It is therefore unlikely that all the necessary housing in the Netherlands - mentioned is a number of one million housing units - can be realised in the existing built-up area. Expansion into rural areas is then inevitable and makes it possible to improve the quality of these rural areas. Densification of the many villages and small towns in our country enable to approach them from the '15-minute principle' as well. Villages should thereby become large enough to support at least a small supermarket, primary school and health centre, but also to accommodate small businesses. A fast and frequent public transport-connection to a city, to other villages and to a railway station in the vicinity is important.
 
A thorny issue is the quality of nature in the rural area. Unfortunately, it is in bad shape. A considerable part of the rural area consists of grass plots with large-scale agro-industrial use and arable land on which cattle feed is grown. Half of the Netherlands is for cows, which, incidentally, are mostly in stalls. Restoring nature in the area that is predominantly characterised by large-scale livestock farming, is an essential task for the coming decades.
 
The development of sufficiently dense built-up areas both in cities and villages and the development of new nature around and within those cities and villages is a beckoning prospect. This can be done by applying the idea of 'scheggen' in and around medium-sized and large cities. These are green zones that penetrate deep into the urban area. New residential and work locations can then join the already built-up area, preferably along existing railway lines and (fast) bus connections. These neighbourhoods can be built in their entirety with movement on foot and by bicycle as a starting point. The centre is a small densely built-up central part, where the desired amenities can be found.
 
In terms of nature development, depending on the possibilities of the soil, I am thinking of the development of forest and heath areas and lush grasslands, combined with extensive livestock farming, small-scale cultivation of agricultural and horticultural products for the benefit of nearby city, water features with a sponge function with partly recreational use, and a network of footpaths and cycle paths. Picture above: nature development and stream restoration (Photo: Bob Luijks) 

Below you can link to my free downloadable e-book: 25 Building blocks to create better streets, neighborhoods and cities

A certain degree of compactness is essential for the viability of 15-minute cities.  This is due to the need for an economic threshold for facilities accessible by walking or cycling. A summary of 300 research projects by the OECD shows that compactness increases the efficiency of public services in all respects. But it also reveals disadvantages in terms of health and well-being due to pollution, traffic, and noise. The assumption is that there is an optimal density at which both pleasant living and the presence of everyday facilities - including schools - can be realised.  At this point, 'densification' is not at the expense of quality of life but contributes to it.  A lower density results in more car use and a higher density will reduce living and green space and the opportunity to create jobs.

The image above is a sketch of the 'Plan Papenvest' in Brussels. The density, 300 dwellings on an area of 1.13 hectares, is ten times that of an average neighbourhood. Urban planners often mention that the density of Dutch cities is much lower than in Paris and Barcelona, for example. Yet it is precisely in these cities that traffic is one of the main causes of air pollution, stress, and health problems. The benefits of compactness combined with a high quality of life can only be realised if the nuisances associated with increasing density are limited. This uncompromisingly means limiting car ownership and use.

Urban planners often seem to argue the other way round. They argue that building in the green areas around cities must be prevented at all costs to protect nature and that there is still enough space for building in the cities. The validity of this view is limited. In the first place, the scarce open space within cities can be better used for clean workshops and nature development in combination with water control. Secondly, much of the 'green' space outside cities is not valuable nature at all. Most of it is used to produce feed for livestock, especially cows. Using a few per cent of this space for housing does not harm nature at all. This housing must be concentrated near public transport. The worst idea is to add a road to the outskirts of every town and village. This will undoubtedly increase the use of cars.
 
Below you can link to my free downloadable e-book: 25 Building blocks to create better streets, neighborhoods and cities

Carlos Moreno, a professor at the Sorbonne University, helped Mayor Anne Hidalgo develop the idea of the 15-minute city. He said that six things made people happy: living, working, amenities, education, wellbeing, and recreation. The quality of the urban environment is enhanced when these functions are realized near each other. The monofunctional expansion of cities in the US, but also in the bidonvilles of Paris, is a thorn in his side, partly because this justifies owning a car.
 
A more precise definition of the concept of the 15-minute city is needed before it can be implemented on a large scale. It is important to clarify which means of transport must be available to reach certain facilities in a given number of minutes. The list of facilities is usually very comprehensive, while the list of means of transport is usually only vaguely defined. But the distance you can travel in 15 minutes depends on the availability of certain modes of transport (see figure above).
Advocates of "new urbanism" have developed the tools to design 15-minute cities. They are based on three zones: the 5-minute walking zone, the 15-minute walking zone, which coincides with the 5-minute cycling zone, and finally the 15-minute cycling zone. These are not static concepts: In practice, the zones overlap and complement each other.

The 5-minute walking zone

This zone corresponds to the way in which most residential neighbourhoods functioned up until the 1960s, wherever you are in the world. Imagine a space with an average distance from the center to the edge of about 400 meters. In the center you will find a limited number of shops, a (small) supermarket, one or more cafes and a restaurant. The number of residents will vary between two and three thousand. Density will decrease from the centre and the main streets outwards. Green spaces, including a small neighbourhood park, will be distributed throughout the neighbourhood, as will workshops and offices.
In the case of new construction, it is essential that pedestrian areas have a dense network of paths without crossings at ground level with streets where car traffic is allowed. Some paths are wider and allow cycling within the 5- and 15-minute cycle zones. The streets provide access to concentrated parking facilities.

The 5-minute cycle zone and the 15-minute walking zone.

Here the distance from the center to the edge is about one kilometer. In this area, most of the facilities that residents need is available and can be distributed around the centers of the 5-minute walking zones. For example, a slightly larger supermarket may be located between two 5-minute walking zones. This zone will also contain one or more larger parks and some larger concentrations of employment.
This zone can be a large district of a city, but it can also be a small municipality or district of around 15 to 25,000 inhabitants. With such a population there will be little room for dogmatic design, especially when it comes to existing buildings. But even then, it is possible to separate traffic types by keeping cars off many streets and clustering car parks. The bottom line is that all destinations in this zone can be reached quickly by walking and cycling, and that car routes can be crossed safely.
The car will be used (occasionally) for several destinations. For example, for large shopping trips to the supermarket.

The 15-minute cycle zone.

This zone will be home to 100.00 or more residents. The large variation is due to the (accidental) presence of facilities for a larger catchment area, such as an industrial estate, a furniture boulevard or an IKEA, a university or a (regional) hospital. It is certainly not a sum of comparable 5-minute cycle zones. Nevertheless, the aim is to distribute functions over the whole area on as small a scale as possible. In practice, this zone is also crossed by several roads for car traffic. The network of cycle paths provides the most direct links between the 5-minute cycle zones and the wider area.
 
The main urban development objectives for this zone are good accessibility to urban facilities by public transport from all neighbourhoods, the prohibition of hypermarkets and a certain distribution of central functions throughout the area: Residents should be able to go out and have fun in a few places and not just in a central part of the city.
 
Below you can link to my free downloadable e-book: 25 Building blocks to create better streets, neighborhoods and cities.

Without changing the transport system in which they operate, the advent of autonomous cars will not significantly improve the quality of life in our cities. This has been discussed in previous contributions. This change includes prioritizing investment in developing high-quality public transport and autonomous minibuses to cover the first and last mile.
 
However, this is not enough by itself. The need to reduce the distances we travel daily also applies to transporting raw materials and food around the world. This is the subject of a new series of blog posts, and probably the last.
Over the next few weeks I will be discussing the sustainability of the need for people and goods to travel long distances. In many cities, the corona pandemic has been a boost to this idea. Paris is used as an example. But what applies to Paris applies to every city.
 
When Anne Hidalgo took office as the newly elected mayor in 2016, her first actions were to close the motorway over the Seine quay and build kilometres of cycle paths. Initially, these actions were motivated by environmental concerns. Apparently, there was enough support for these plans to ensure her re-election in 2020. She had understood that measures to limit car traffic would not be enough. That is why she campaigned on the idea of "La Ville du Quart d'Heure", the 15-minute city, also known as the "complete neighbourhood". In essence, the idea is to provide citizens with almost all of their daily needs - employment, housing, amenities, schools, care and recreation - within a 15-minute walk or bike ride of their homes. The idea appealed. The idea of keeping people in their cars was replaced by the more sympathetic, empirical idea of making them redundant.
 
During pandemics, lockdowns prevent people from leaving their homes or travelling more than one kilometer. For the daily journey to work or school, the tele-works took their place, and the number of (temporary) "pistes á cycler" quickly increased. For many Parisians, the rediscovery of their own neighbourhood was a revelation. They looked up to the parks every day, the neighbourhood shops had more customers, commuters suddenly had much more time and, despite all the worries, the pandemic was in a revival of "village" coziness.
 
A revival, indeed, because until the 1960s, most of the inhabitants of the countries of Europe, the United States, Canada and Australia did not know that everything they needed on a daily basis was available within walking or cycling distance. It was against this backdrop that the idea of the 15-minute city gained ground in Paris.
 
We talk about a 15-minute city when neighbourhoods have the following characteristics
- a mix of housing for people of different ages and backgrounds - pedestrians and cyclists
- Pedestrians and cyclists, especially children, can safely use car-free streets.
- Shops within walking distance (up to 400 meters) for all daily needs
- The same goes for a medical center and a primary school.
- There are excellent public transport links;
- Parking is available on the outskirts of the neighbourhood.
- Several businesses and workshops are located in each neighbourhood.
- Neighbourhoods offer different types of meeting places, from parks to cafes and restaurants.
- There are many green and leafy streets in a neighbourhood.
- The population is large enough to support these facilities.
- Citizens have a degree of self-management.
 
Urban planners have rarely lost sight of these ideas. In many cities, the pandemic has made these vague memories accessible goals, even if they are far from reality.
 
In the next post, I will reflect on how the idea of the 15-minute city is moving from dream to reality.

Below you can link to my free downloadable e-book: 25 Building blocks to create better streets, neighborhoods and cities