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Tag Archives: Spatial analysis

Data

There are lots of interesting things going on using data in cities at the moment. Many articles and blog posts talk about how data, and open data in particular, has the potential to deliver public services better, start to address long-term outcomes (such as health problems), and create a basis for decision-making. In times when public sector funding is under pressure delivering these outcomes is even more important than normal.

Collecting data in cities is helpful as it provides something to measure progress against. It means measuring specific outcomes, which also means being very precise about what outcomes are important.

It can also be a link between deciding a wider objective (improve air quality) and a specific implementable actions (make public transport free). However, to do this requires both domain and data expertise:

  • to understand the difference between data on the outcomes of a system, and the variables in that system
  • to measure and analyse the urban systems that form the variables
  • to know how data is recorded on urban systems and what it actually represents Read More

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This is both a follow-up to an earlier post on filtered permeability in de Beauvoir, and a response to the current Walford Road area consultation.

The earlier post identified three negative impacts of filtered permeability:

  1. Filtered permeability breaks the street network and pushes traffic away from “residential streets” on to the surrounding roads which increases congestion, air pollution, and journey times.
  2. By describing these areas as “residential streets” it implies that no one lives anywhere else. Often the streets that traffic is filtered towards are actually high streets with higher densities and a wider mix of uses. There are consequently more people on them, and therefore more people exposed to increased traffic and air pollution.
  3. The streets where traffic has been restricted are already quiet, and experience further reductions in natural surveillance, reducing personal safety (and the perception of safety).

These points were made on the basis of street network analysis, and some further investigations in to the distribution of land use and density in and around de Beauvoir.

A further consideration in the earlier study is that the resulting distribution of traffic volumes (and air pollution) is socio-economically distorted: higher density, multi-dwelling, buildings are more exposed to traffic, while lower density houses are less exposed.

The drive for filtered permeability is to encourage cycling, and this is positive for many reasons. However, cities are complex systems that work across many scales simultaneously, and are formed from different layers of infrastructure, public transport, land use, density, and people, all of which need to be considered in an integrated way.

The last fifty years of urban planning, and specifically the dominance of traffic engineering, shows how negative outcomes for the whole city arise by working with one infrastructure system in isolation from the others. Despite the positive objective, the risk of using filtered permeability to try to deliver improved cycling infrastructure is that it will create unintended negative outcomes across the wider area.

Hackney council currently has a consultation running to extend a filtered permeability scheme further north into Stoke Newington. This post uses spatial network analysis to test the impact of these new proposals.

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A couple of weeks back the Design Council Newsletter re-published some work from 2014, looking at how Hackney had become one of the most liveable boroughs in London. This is evidenced by an increase in people cycling to work and a decline in those driving – both around or over 10%.

One of the reasons set out for this change in behaviour is the success of policies implemented over the last 10 years, which include re-designing residential streets. In particular the use of “filtered permeability” – using bollards to make some streets only accessible to pedestrians and cyclists – is described as part of this achievement.

Increasing active travel share and decreasing private car use is very positive, however, closing streets immediately raises questions around the wider impacts.

In a very quick summary there are three major issues with filtered permeability:

  • Fragmented networks increase congestion and lengthen car trips
  • Increased likelihood of air pollution in higher density, mixed use areas
  • Reduced levels of natural surveillance impact personal safety

These points are expanded in the post below: Read More

This is a research paper I recently presented at the 11th Space Syntax Symposium in Lisbon, co-authored with Stephen Law and Laurens Versluis.

The paper has been reformatted for re-production here and the original published version can be found here .

 

Abstract

This paper describes an exploratory methodology used to study the national scale issues of population growth and infrastructure implementation across the UK. The project was carried out for the Government Office for Science in 2015, focussing on two key questions: how could a “spatially driven” scenario provoke new thinking on accommodating forecast growth, and; what would be the impact of transport infrastructure investments within this context.

Addressing these questions required the construction of a national scale spatial model that also needed to integrate datasets on population and employment. Models were analysed and profiled initially to identify existing relationships between the distribution of population and employment against the spatial network. Based on these profiles, an experimental methodology was used to firstly identify cities with the potential to accommodate growth, then secondly to allocate additional population proportionally. This raises important questions for discussion around which cities provide the benchmark for growth and why, as well as what the optimal spatial conditions for population growth may be, and how this growth should be accommodated locally.

Later the model was used to study the impact of High Speed Rail. As these proposed infrastructure changes improve service (capacity, frequency, journey time), rather than creating new topological connections, the model was adapted to be able to produce time based catchments as an output. These catchments could then be expressed in terms of the workforce population within an hour of every city (a potential travel to work area), as well as the number of employment opportunities within an hour of every household.

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These are the notes from the session I was part of at Friday’s Digital Transport Exchange.

 

How can we best collaborate to improve personal mobility?

There are two issues behind this question:

Firstly, that personal mobility isn’t as good as it should be. This is one of the big issues that’s raised a lot at the moment all around the world. Especially how the combined costs of mobility and housing is pushing people further out of cities and/or detrimentally affecting their daily lives.

This is not just an issue about how to provide mobility services, but it’s a wider issue around a planning and design.

Secondly, collaboration is not as good as it should be. This includes sophisticated disciplines working in parallel, differences between public and private sectors, short- and long-term decision makers, and divisions within large organisations. The result of this is that the outcomes of design, planning and service strategies optimise individual systems rather than creating combined outcomes that benefit the wider city.

By using urban analytics that are strategic in nature, precisely link people to space, and focus on outcomes not systems, we can start to address these issues.

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This is the combination of a couple of talks I’ve given in the last few months to the ULI Urban Tech Committee and the Academy of Urbanism Digital Urbanism groups.

Urban Tech is something that has developed a lot in the last 10 years and which now seems to have a lot of interest and attention. There are a lot of terms – Future Cities, Smart Cities, Prop Tech, Urban Tech, etc – which are all slightly related but not quite connected in the way they could be.

One way of trying to understand how they fit together is by tracing what has changed in this time and what this means for the way we interact with cities.

While its interesting to see how things have changed, what is possibly more important, as professionals who work with, and in the context of cities, is to ask the more difficult “so what” questions of why things should change?

Here’s an outline of the reasons Why that will be explained in more detail below:

  • Better outcomes for cities and people
  • Creating benefits between public and private sectors in the short and long terms
  • More transparent and inclusive decision-making
  • Crossing siloes between planning and service delivery for more effective and efficient spending

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