Category: Planning

Categories
Planning

Resilient by Design

I have a new article out now in Transportation Research Part A: Policy and Practice. Here’s a free open-access preprint if you lack institutional access.

We simulate over 2.4 billion trips across every urban area in the world to measure street network vulnerability to disasters, then measure the relationships between street network design and these vulnerability indicators.

First we modeled the street networks of more than 8,000 urban areas in 178 countries. Then, for each urban area, we simulated disasters of 3 different types (representing floods, earthquakes, and targeted attacks) and 10 different extents. Then we simulated over 2.4 billion trips on these networks to measure how certain trips become more circuitous or even impossible to complete as parts of the network fail after a disaster. Finally we built a model to predict how much a disaster would impact trips.

Continue reading “Resilient by Design”
Categories
Planning

Street Network Design and GHG Emissions

I have a new article out in Transportation Research Part D that estimates relationships between street network characteristics and transport CO2 emissions across every urban area in the world and investigates whether they are the same across development levels and design paradigms.

The relationships between street network design and transport emissions in the US, Europe, and China are well-studied. But not so in many of the most rapidly developing parts of the world. Practitioners lack a strong local evidence base for local evidence-informed planning.

Continue reading “Street Network Design and GHG Emissions”
Categories
Planning

Rethinking the One-Way Street

I recently published an article in Transfers Magazine with Billy Riggs questioning some of the received wisdom about one-way streets and efficiency. This builds on our recent research published in JPER modeling vehicle distance traveled before and after hypothetical one-way to two-way street conversions.

Continue reading “Rethinking the One-Way Street”
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.

Continue reading “Air Pollution Exposure in Los Angeles”
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.

Continue reading “Two-Way Streets and Network Efficiency”
Categories
Planning

Framework for Measuring Pedestrian Accessibility

I’m a co-author of a new article, “A Generalized Framework for Measuring Pedestrian Accessibility around the World Using Open Data,” which has just been published by Geographical Analysis. We developed an open source, containerized software framework for modeling pedestrian networks using open data to analyze disaggregate access to daily living needs. We worked with local partners in 25 cities around the world to demonstrate and validate this toolkit.

From the abstract:

Pedestrian accessibility is an important factor in urban transport and land use policy and critical for creating healthy, sustainable cities. Developing and evaluating indicators measuring inequalities in pedestrian accessibility can help planners and policymakers benchmark and monitor the progress of city planning interventions. However, measuring and assessing indicators of urban design and transport features at high resolution worldwide to enable city comparisons is challenging due to limited availability of official, high quality, and comparable spatial data, as well as spatial analysis tools offering customizable frameworks for indicator construction and analysis. To address these challenges, this study develops an open source software framework to construct pedestrian accessibility indicators for cities using open and consistent data. It presents a generalized method to consistently measure pedestrian accessibility at high resolution and spatially aggregated scale, to allow for both within- and between-city analyses. The open source and open data methods developed in this study can be extended to other cities worldwide to support local planning and policymaking. The software is made publicly available for reuse in an open repository.

For more, check out the article.

Categories
Planning

Robert Moses Responds to Robert Caro

In 1974, Robert Caro published The Power Broker, a critical biography of Robert Moses’s dictatorial tenure as the “master builder” of mid-century New York. Moses profoundly transformed New York’s urban fabric and transportation system, producing the Brooklyn Battery Tunnel, the Verrazano Narrows Bridge, the Westside Highway, the Cross-Bronx Expressway, the Lincoln Center, the UN headquarters, Shea Stadium, Jones Beach State Park and many other projects. However, The Power Broker did lasting damage to his public image and today he remains one of the most controversial figures in city planning history.

Today, The Power Broker may be the most well-known biography of any urban planner ever. Less-known: on August 26, 1974, Moses issued a turgid 23-page statement denouncing Caro’s work as “full of mistakes, unsupported charges, nasty baseless personalities, and random haymakers.” Moses’s original typewritten statement survives today as a grainy photocopy in the New York City Parks Department archive. To better preserve and disseminate it, I extracted and transcribed its text using optical character recognition and edited the result to correct errors. My transcription of Moses’s statement, alongside Caro’s response to it, is available here.

Categories
Planning

Off the Grid… and Back Again?

My article “Off the Grid… and Back Again? The Recent Evolution of American Street Network Planning and Design” has been published by the Journal of the American Planning Association and won the 2020 Stough-Johansson Springer Award for best paper. It identifies recent nationwide trends in American street network design, measuring how urban planners abandoned the grid and embraced sprawl over the 20th century, but since 2000 these trends have rebounded, shifting back toward historical design patterns. In this post I discuss these findings and visualizations across the US today as well as over time, then discuss my analysis methods.

Map of where street grids exist today across the US, made with OSMnx and Python

Continue reading “Off the Grid… and Back Again?”