Categories
Planning

Air Pollution Exposure in Los Angeles

I have a new article out now in Urban Studies, which finds that—all else equal—residents of Los Angeles census tracts that generate more vehicular travel tend to be exposed to less vehicular air pollution, and that tracts with a larger non-white population proportion—whether high- or low-income—experience more air pollution than do whiter but otherwise similar tracts. There’s also a free, open access pre-print available.

Twentieth century planners designed and constructed an enormous network of expressways to open up growing American metropolises to motorists. Vast swaths of established urban neighborhoods were bulldozed to clear new channels for suburban residents to drive to job centers. Yet some older neighborhoods survived relatively unscathed.

For example, in Los Angeles, local residents organized to protest and eventually successfully cancel plans to extend State Route 2 through the affluent communities of Beverly Hills and Los Angeles’s westside. In contrast, similar grassroots efforts failed in Los Angeles’s eastside, where several major freeways carved up its less-affluent and less-white neighborhoods.

Categories
Data

Urban Analytics: History, Trajectory and Critique

I have a new chapter titled “Urban Analytics: History, Trajectory and Critique,” co-authored with Mike Batty, Shan Jiang, and Lisa Schweitzer, now published in the Handbook of Spatial Analysis in the Social Sciences, edited by Serge Rey and Rachel Franklin.

From our abstract:

Urban analytics combines spatial analysis, statistics, computer science, and urban planning to understand and shape city futures. While it promises better policymaking insights, concerns exist around its epistemological scope and impacts on privacy, ethics, and social control. This chapter reflects on the history and trajectory of urban analytics as a scholarly and professional discipline. In particular, it considers the direction in which this field is going and whether it improves our collective and individual welfare. It first introduces early theories, models, and deductive methods from which the field originated before shifting toward induction. It then explores urban network analytics that enrich traditional representations of spatial interaction and structure. Next it discusses urban applications of spatiotemporal big data and machine learning. Finally, it argues that privacy and ethical concerns are too often ignored as ubiquitous monitoring and analytics can empower social repression. It concludes with a call for a more critical urban analytics that recognizes its epistemological limits, emphasizes human dignity, and learns from and supports marginalized communities.

For more, check out the chapter.

Categories
Planning

Delivering Healthy and Sustainable Cities

I have a new article out now in The Journal of City Climate Policy and Economy, coauthored with a team that includes several of the folks from our recent series in The Lancet Global Health. The JCCPE article, “A Pathway to Prioritizing and Delivering Healthy and Sustainable Cities,” synthesizes findings and recommended policy actions arising from that recent TLGH series.

From the abstract:

Creating healthy and sustainable cities should be a global priority. Some cities prioritize 15-minute cities as a planning approach with co-benefits for health, climate change mitigation, equity, and economic recovery from COVID-19. Yet, as our recent The Lancet Global Health series on “Urban Design, Transport, and Health” showed, many cities have a long way to go to achieve this vision. This policy guideline summarizes the main findings of the series, which assessed health and sustainability indicators for 25 cities in 19 countries. We then outline steps governments can take to strengthen policy frameworks and deliver more healthy, equitable, and sustainable built environments. The Lancet Global Health series provided clear evidence that cities need to transform urban governance to enable integrated planning for health and sustainability and commit to policy implementation. Evidence-informed indicators should be used to benchmark and monitor progress. Cities need policy frameworks that are comprehensive and consistent with evidence, with measurable policy targets to support implementation and accountability. The series provided evidence-informed thresholds for some key urban design and transport features, which can be embedded as policy targets. Policies and interventions must prioritize identifying and reducing inequities in access to health-supportive environments. Governments should also invest in open data and promote citizen-science programmes, to support indicator development and research for public benefit. We provide tools to replicate our indicators and an invitation to join our 1,000 Cities Challenge via the Global Observatory of Healthy and Sustainable Cities.

For more, check out the JCCPE article itself. And you may also be interested in our recent The Lancet Global Health series of articles that developed similar themes in great depth.

Categories
Planning

ISPAH in Abu Dhabi

Alongside Billie Giles-Corti and Jim Sallis, I will be presenting our team’s recent research into accessible, sustainable urban design around the world at the ISPAH Congress in Abu Dhabi this week. Our symposium at the congress will share the methods and findings from our The Lancet Global Health series published this summer, as well as our ongoing work on the Thousand Cities Challenge.

Our geospatial team developed open-source software to calculate indicators of walkability and accessibility around the world, and then linked these back to cities’ policy contexts and identified populations living above and below estimated thresholds for physical activity. Few cities had measurable policy standards and targets to actually build healthier and more sustainable cities, and their health-supportive built environment features were often inadequate or inequitably distributed.

We simultaneously launched the Global Observatory of Healthy and Sustainable Cities to promote healthy and sustainable urban planning, benchmark and monitor cities’ progress, and share more consistent, comparable urban data. The whole series of articles is free and open access, as is our software.

Categories
Planning

Two-Way Streets and Network Efficiency

I have a new article out now in the Journal of Planning Education and Research with Billy Riggs, in which we examine how two-way street conversions impact street network efficiency. Most of the efficiency literature looks at the benefits of one-way streets for signalization and vehicular throughput. We took a different approach, considering how one-way streets inherently increase travel distances.

Categories
Urban

The Lancet Global Health Series on Urban Design, Transport, and Health

After many years of hard work, our series of articles on urban design, transport, and health has been published by The Lancet Global Health.

The Lancet Global Health infographic on benchmarking healthy sustainable citiesIn our first paper, we analyzed urban policies and calculated built environment indicators for 25 cities across 6 continents to assess walkability and accessibility. Our policy analysis found policies inconsistent with public health evidence, rhetoric endorsing health and sustainability but few measurable policy targets, and substantial implementation gaps.

Categories
Data

OSMnx v1.1 Released

OSMnx v1.1.0 has been released. It includes several new features, bug fixes, and performance enhancements. I encourage you to upgrade and take advantage of everything new. I’ll summarize some of the key improvements in this post.

Categories
Data

Worldwide Street Network Models and Indicators

My article, “Street Network Models and Indicators for Every Urban Area in the World” has been published by Geographical Analysis. This project was a massive undertaking and I’m excited to share it. As you might guess from the title, I modeled and analyzed the street network of each urban area in the world then deposited all the source code and models and indicators in open repositories for public reuse. The article also includes a high-level analysis of urban street network form across the world.

Cities worldwide exhibit a variety of street patterns and configurations that shape human mobility, equity, health, and livelihoods. Using boundaries derived from the Global Human Settlement Layer, I modeled and analyzed the street networks of every urban area in the world using OSMnx and OpenStreetMap raw data. In total, I modeled over 160 million street network nodes and over 320 million edges across 8,914 urban areas in 178 countries. I attached node elevations and street grades to every node/edge in the final models. All the final models were topologically simplified such that nodes represent intersections and dead-ends, and edges represent the street segments linking them.

Street network topology simplification with OSMnx and OpenStreetMap

Categories
Data

GIS and Computational Notebooks

I have a new chapter “GIS and Computational Notebooks,” co-authored with Dani Arribas-Bel, out now in The Geographic Information Science & Technology Body of Knowledge. Want to make your spatial analyses more reproducible, portable, and well-documented? Our chapter is a short, gentle intro to using code and notebooks for modern GIS work.

Science and analytics both struggle with reproducibility, documentation, and portability. But GIS in both research and practice particularly suffers from these problems due to some of its unique characteristics. Our chapter discusses this challenge and its urgency for building better and more actionable knowledge from geospatial data. Then we introduce an emerging solution, the computational notebook, using Jupyter as our central example to illustrate what it does and how it works.

Jupyter notebook JupyterLab user interface

Categories
Urban

Urban Form and OpenStreetMap

My chapter “Exploring Urban Form Through OpenStreetMap Data: A Visual Introduction” has just been published in the new book Urban Experience and Design: Contemporary Perspectives on Improving the Public Realm edited by Justin Hollander and Ann Sussman.

From the abstract:

This chapter introduces OpenStreetMap—a crowdsourced, worldwide mapping project and geospatial data repository—to illustrate its usefulness in quickly and easily analyzing and visualizing planning and design outcomes in the built environment. It demonstrates the OSMnx toolkit for automatically downloading, modeling and visualizing spatial data from OpenStreetMap. We explore patterns and configurations in street networks and buildings around the world computationally through visualization methods—including figure-ground diagrams and polar histograms—that help compress urban complexity into comprehensible artifacts that reflect the human experience of the built environment. Ubiquitous urban data and computation can open up new urban form analyses from both quantitative and qualitative perspectives.

For more, check out the chapter.