Monday, April 20, 2020

We are moving to a new home: Urban Demographics 2.0

NOTE: This website has moved to a new address at This content has not been updated since April 2020.

After 1530 blog posts and 471 thousand pageviews over a period of 9 years and 10 months, we are moving to Urban Demographics 2.0, at urbandemographics.orgI will keep a frozen version of this blogspot website online for the record, but I won't be updating any content.

Blogger has been a good companion for a long time, but I felt it was time to move on to a more flexible and versatile platform. Urban Demographics 2.0 is entirely written from within R using blogdown and Hugo. You can find more info in the 1st post of the new website :)

If you follow UD updates via RSS, I am trying move our feed to the new website so you don't have to do anything. I hope this won't break things, but this is our new feed if you want to make sure not to miss any new posts. The Twitter and Facebook channels remain unchanged.

See you on the other side

Photo by Toa Heftiba


Monday, April 13, 2020

The delineation and growth of metropolitan areas in the world between 2000 and 2015

A talented team at the OECD and the European Union have developed a consistent method to delineate metropolitan areas – or functional urban areas (FUAs) – in the entire world. They recently published an open access paper where the explain the method and use it to analyze the population growth of metropolitan areas in the world between 2000 and 2015. You can find more info about the paper below and  a geopackage data set of  FUAs can downloaded from here

Moreno-Monroy, A. I., Schiavina, M., & Veneri, P. (2020). Metropolitan areas in the world. Delineation and population trends. Journal of Urban Economics, 103242. 

This paper presents a novel method to delineate metropolitan areas – or functional urban areas (FUAs) – in the entire world and assesses their population trends. According to the definition developed by the OECD and the European Union, FUAs are composed of high-density urban centres with at least 50 thousand people plus their surrounding commuting zones. The latter represent the urban centres’ areas of influence in terms of labour market flows. The proposed method combines a functional and a morphological approach to overcome the dependency on travel-to-work data to define commuting zones and allow a global delineation. It relies on a probabilistic approach and the use of population and travel impedance gridded data across the globe. Results show that around 3.9 billion people, making up 53% of the world population, live in 8,790 FUAs, out of which 17% live in their commuting zones. Between 2000 and 2015, population growth was higher in larger FUAs, highlighting a general trend toward higher concentration of the metropolitan population. Commuting zones grew faster than urban centres, though with heterogeneous patterns across world regions, income levels and metropolitan size.

Related posts:

Friday, April 10, 2020

COVID-19 pandemic and access to healthcare in Brazil's largest cities

The Institute for Applied Economic Research (Ipea) published yesterday our study looking at 'Urban mobility and access to the healthcare system by patients with suspected and severe cases of COVID-19 in the 20 largest cities of Brazil'. The work is published in Portuguese but there is a Twitter thread with the main findings. In any case, I included a summary of the publication in English below.

obs. This is a by-product of the Access to Opportunities Project. I'm grateful for an amazing team of co-authors who helped me put this piece together in such a short time.


The Covid-19 epidemic crisis is causing a rapid growth in the number of hospitalizations for severe acute respiratory syndrome (SARS) in Brazil. According to recent studies, this could soon overload the country's public health system (SUS). As of this writing, most of the confirmed cases of Covid-19 are concentrated in the country's largest cities, where the spread of the disease is at a rapid pace and affecting a growing number of people in disadvantaged communities.

In this policy report, we analyze accessibility to healthcare services in Brazil's 20 largest cities. The research focuses on how easily patients with suspected and severe cases of COVID-19 could reach public health facilities. The study has two purposes:
  1. In the first half of the report we estimate how many vulnerable people (low-income above 50 years old) live in areas with poor access to healthcare facilities that could either screen suspected cases of Covid-19 or provide hospitalization of severe cases with the support of ICU beds and mechanical ventilators.
  2. In the second half, we estimate the ratio between the number of ICU beds and mechanical ventilators available at each hospital and the population living withing its catchment area.
These two analyses combined provide actionable information to local authorities. The study puts disadvantaged communities with poor access to health services on the map, indicating in which neighborhoods local authorities could build makeshift hospitals or develop strategies via pre-hospital care with mobile units or through the work of health community agents. This research also helps local authorities identify which hospitals could more likely struggle with the rising demand for hospitalizations, and hence would need investments to expand capacity.

Tuesday, April 7, 2020

Assorted Links on COVID19

I must say I've been feeling saturated and underwhelmed by the number of data analysts who suddenly became public health and epidemiology experts creating so many data dashboards on COVID-19. There I said it.

Having said that, there many interesting and intelligent people working to understand how the COVID-19 epidemic affects and is affected by demography and human mobility patterns, and how these relationships intersect with and reveal our socioeconomic inequities. I've selected some of the best pieces on the coronavirus crisis I've come across so far.
  1. Our World in Data: possibly one the best websites to get updated data and interactive visualizations, by Max Roser and an amazing team at Oxford.

  2. Google published a series of Community Mobility Reports ... in PDF format !!! Fortunately, you can find the data in .csv here, scraped by Vitor Batista

  3. The effect of human mobility and control measures on the COVID-19 epidemic in China. Paper by Moritz Kraemer et al.

  4. Changes in nighttime lights reveal a dramatic decrease in Wuhan following the COVID-19 outbreak, via Joshua Stevens (one of  my favorite Twitter accounts)

  5. Kuan Butts shows the dramatic impact quarantining has had in road traffic in major cities around the world

  6. How much is air traffic down from normal levels? More than half, by Niko Kommenda for The Guardian

  7. Satellite images show pollution on the decline in the US and Europe

  8. The coronavirus epidemic has also significantly decreased public transport ridershiprestaurant bookings, retail activities, energy use and congestion levels

  9. My all favorite. Article on the NYT illustrate how quarantine is a class and racial privilege. Smartphone location data reveals how many lower-income workers continue to move around in cities across the U.S., while wealthier people 'can afford' to stay home and limit their exposure to the coronavirus. Brilliant piece by Jennifer Valentino-DeVries, Denise Lu and Gabriel Dance.

Wednesday, March 18, 2020

Sunday, March 8, 2020

Call for papers: Advances in Spatial and Transport Network Analysis

The Int Journal of Geo-information has opened a call for papers for special issue on "Advances in Spatial and Transport Network Analysis". This issue is edited by Henrikki Tenkanen, Elsa Arcaute, Marta C. Gonzalez and myself. This is a great opportunity to create a dialogue between network and social scientists, transport geographers, engineers etc working on transport and mobility networks. This dialogue raises new challenges, though, as discussed in this thoughtful recent paper by Tim Schwanen.

Here is a short snippet of the cfp:
"This Special Issue is dedicated to papers focusing on recent advances in the development of new measures and methodologies to evaluate and analyze the performance of transportation networks. These measures might include, but are not limited to, environmental costs or exposures (e.g., CO2 , noise, pollution); monetary costs (the price of access), complexity, and resilience of multimodal transportation networks; or focus on qualitative aspects of travel, where travel might be seen as a gain instead of cost (such as exposure to aesthetic or green environments). Methodologically, we welcome works using novel ways to measure transport network connectivity, performance, and accessibility, including recent advances in machine learning and AI. Special attention will be paid to papers studying transport-related questions with interdisciplinary approaches."

Thursday, March 5, 2020

New paper out: Disparities in travel times between cars and public transport

I am very glad to share our new paper looking at the travel time gap between private and public transport at high spatial and temporal resolutions. The study combines real-time traffic data, transit data, and travel demand estimated using Twitter data to compare this travel time gap in four cities (São Paulo, Stockholm, Sydney and Amsterdam).

Despite remarkable differences between these cities in terms of transportation networks, area, and population size, we found travel times of transit and vs. driving are surprisingly similar across cities: R < 1 for trips shorter than 3km, then increases rapidly but quickly stabilizes at 2 (figure below). Moreover, using public transport generally takes on average 1.4–2.6 times longer than driving a car. The share of area where travel time favors public transport over car use is also very small in all cities. As Giulio Mattioli noted on Twitter, these results 'would confirm that car dependence is much more than just a question of culture & attitudes'.

The paper is open access and it was written in collaboration with a great team led by Yuan Liao and Sonia Yeh at University of Chalmers, Sweden.

Liao, Y., Gil, J., Pereira, R.H.M. et al. Disparities in travel times between car and transit: Spatiotemporal patterns in cities. Scientific Reports 10, 4056 (2020).

Cities worldwide are pursuing policies to reduce car use and prioritise public transit (PT) as a means to tackle congestion, air pollution, and greenhouse gas emissions. The increase of PT ridership is constrained by many aspects; among them, travel time and the built environment are considered the most critical factors in the choice of travel mode. We propose a data fusion framework including real-time traffic data, transit data, and travel demand estimated using Twitter data to compare the travel time by car and PT in four cities (São Paulo, Brazil; Stockholm, Sweden; Sydney, Australia; and Amsterdam, the Netherlands) at high spatial and temporal resolutions. We use real-world data to make realistic estimates of travel time by car and by PT and compare their performance by time of day and by travel distance across cities. Our results suggest that using PT takes on average 1.4–2.6 times longer than driving a car. The share of area where travel time favours PT over car use is very small: 0.62% (0.65%), 0.44% (0.48%), 1.10% (1.22%) and 1.16% (1.19%) for the daily average (and during peak hours) for São Paulo, Sydney, Stockholm, and Amsterdam, respectively. The travel time disparity, as quantified by the travel time ratio R (PT travel time divided by the car travel time), varies widely during an average weekday, by location and time of day. A systematic comparison between these two modes shows that the average travel time disparity is surprisingly similar across cities: R < 1 for travel distances less than 3 km, then increases rapidly but quickly stabilises at around 2. This study contributes to providing a more realistic performance evaluation that helps future studies further explore what city characteristics as well as urban and transport policies make public transport more attractive, and to create a more sustainable future for cities

The relationship between travel distance and travel time ratio R (PT travel time divided by the car travel time)

Wednesday, March 4, 2020

Six open positions in the Access to Opportunities Project

We are hiring six research assistants to work with me on the Access to Opportunities Project, at the Institute for Applied Economic Research (Ipea). Applications will be open until the 12th of March 2020. More details can be found here (info in Portuguese only).

We are looking for driven candidates with good data analysis skills in R and interested in evaluating policy impacts on issues of transport accessibility and urban inequalities.

Please, help spread us the word!

Tuesday, March 3, 2020

Perspectives and challenges of Smart (and inclusive) Cities in Brazil

I will be on a Facebook Live today discussing some of the challenges of developing Smart and inclusive (!) Cities in Brazil. The Live is being organized by the National Industry Confederation (CNI) and it starts at 5:30pm GMT on this link. The event will be conducted in Portuguese, but please feel free to drop in any comments and questions in any language you prefer.

You can find the recorded video below.

Monday, March 2, 2020

geobr v1.2 is on CRAN

geobr is an R package to download official spatial data sets of Brazil. It includes more than 20 data sets available at various geographic scales and for various years with harmonized attributes, projection and topology

News in this release: 
  • the package is much faster 
  • new data on metropolitan areas : read_metro_areas
  • new data on municipal seats (sede dos municipios) : read_municipal_seat
  • new fun to look up code of municipalities : lookup_muni
  • new fun to list all data sets available in geobr : list_geobr

Thursday, February 13, 2020

Apply for the 2020 Lee Schipper Memorial Scholarship for Sustainable Transport and Energy Efficiency

Since 2012, WRI Ross Center for Sustainable Cities awards a young researcher every year with the Lee Schipper Memorial Scholarship for Sustainable Transport and Energy Efficiency. This award was created to celebrate Lee Schipper, one of the founders of EMBARQ and an enthusiastic supporter of building closer links between rigorous research and policy-making. The Scholarship awards up to two candidates a maximum of $10,000 each to advance transformative research in efficient and sustainable transport. Applications are due by March 18, 2020.

I was honored along with Joanna Moody to receive this award in 2017. It was a great and enriching experience and I would strongly encourage other researchers to apply for the Lee Schipper Award.

The media coverage of 'sustainable mobility'

Monday, February 3, 2020

Hacking the system with virtual traffic congestions

In a brilliant artistic performance, Simon Weckert generated virtual traffic jams in Google Maps by pulling a wagon full of smartphones. HT Steven Crowley.

Sunday, February 2, 2020

Estimating total fertility rates from population pyramids

Matt Hauer and Carl Schmertmann (both on Twitter) have just published a new paper that promises to be a game changer in population studies. They devised a method to estimate total fertility rates using inputs as minimal as the age/sex structure of a population. They tested the accuracy of the method using 2400+ fertility schedules and the result is incredibly accurate. Matt has written a thread on Twitter summarizing some of the key aspects of the paper.  The code to replicate the paper is here and an ungated preprint of the paper can be downloaded here.

Hauer, M., & Schmertmann, C. (2018). Population pyramids yield accurate estimates of total fertility rates. Demography.  []

The primary fertility index for a population, the total fertility rate (TFR), cannot be calculated for many areas and periods because it requires disaggregation of births by mother’s age. Here we discuss a flexible framework for estimating TFR using inputs as minimal as a population pyramid. We develop five variants, each with increasing complexity and data requirements. We test accuracy across a diverse set of data sources that comprise more than 2,400 fertility schedules with known TFR values, including the Human Fertility Database, Demographic and Health Surveys, U.S. counties, and nonhuman species. We show that even the simplest and least accurate variant has a median error of only 0.09 births per woman over 2,400 fertility schedules, suggesting accurate TFR estimation over a wide range of demographic conditions. We anticipate that this framework will extend fertility analysis to new subpopulations, periods, geographies, and even species. To demonstrate the framework’s utility in new applications, we produce subnational estimates of African fertility levels, reconstruct historical European TFRs for periods up to 150 years before the collection of detailed birth records, and estimate TFR for the United States conditional on race and household income.

Estimated TFR from Population Pyramids. We compare the performance of five variants against observed TFRs using data from the Human Fertility Data, Demographic and Health Surveys, the US Census Bureau, and various non-human species.

Wednesday, January 29, 2020

Why cities should focus on promoting accessibility, not mobility

Amit Bhatt (WRI) has written a very eloquent piece on why cities should focus on promoting accessibility, not mobility. Good read.

Tuesday, January 28, 2020

Call for Applications: ITF Young Researcher of the Year Award

The International Transport Forum (ITF) at the OECD has opened a call for applications for the 2020 Young Researcher of the Year Award. The winner of the Award will be invited to present her/his work at the ITF Annual Summit.

"The principal aim of the International Transport Forum’s Young Researcher of the Year Award is to highlight the importance of transport research for sound transport policy formulation and implementation, and to foster closer links between transport policy and research. For 2020, the theme of the Summit is 'Transport Innovation for Sustainable Development'."

I was really honored to receive this award last year and it was a truly great experience. If you are eligible, I would highly recommend you apply for this award. The application is "open to researchers under 35 years of age at the time of closing of applications who have undertaken the research presented in the submitted paper in an institution, university or consultancy firm located in a member country of the ITF/OECD".

Thursday, January 23, 2020

First results of Access to Opportunities Project are now online

Last week, we officialy launched the Access to Opportunities Project. In this first edition of the project (2019) we present accessibility estimates by active transport modes (walking and cycling) for the 20 largest cities in the Brazil, and by public transport for 7 major cities (São Paulo, Rio de Janeiro, Belo Horizonte, Recife, Fortaleza, Porto Alegre e Curitiba).

At the occasion of the event, we launched the website of the project where one can find:
  1. a published report analyzing inequalities in access to opportunities in Brazil's largest cities (report only available in Portuguese)
  2. an interactive map to explore the results
  3. the data outputs of the project
  4. the computational code used to process, analyze and visualize the data
Here is a quick demo of the interactive map but please go ahead and try it for yourself. The app scales fairly well despite the massive amount of data, thanks to Kauê Braga's work using in R to create a mapdeck application in shiny.

Saturday, January 11, 2020

Is this Transit Oriented Development (TOD) ?

Aerial footage of the Maeklong Rail Market, Thailand. Captured by the talented Demas Rusli ( Instagram, Twitter).

Sunday, January 5, 2020

Plotting the metropolitan areas of Brazil in R

Here is a simple R script to download the shape files of Brazilian metropolitan areas by year and plot them in R.

obs. It's important to note that, since the 1988, metro areas are created by state governments. As a rule, this is done with absolutely no transparency nor any technical criteria. It is this legal issue, rather than the urbanization process in the country itself, that led to such an inflated increase in the number of metro areas in the country over the past two decades.

Number of metro areas in Brazil:
1970: 9
2001: 24 
2018: 77

Wednesday, January 1, 2020

Procrastination is not about productivity

Procrastination is “a way of coping with challenging emotions and negative moods induced by certain tasks — boredom, anxiety, self-doubt”. At its core, it’s about emotions, not productivity. 

This is from this brilliant article written by Charlotte Lieberman for the NYT, probably the best piece on procrastination I’ve ever read.