Thursday, October 27, 2016

The impact of public transport on traffic congestion

"... we find that average highway delay increases 47 percent when transit service ceases."

This is from a 2014 paper by Michael Anderson (Berkeley), analyzing the impacts of public transport on traffic congestion in Los Angeles. An ungated working-paper version is available here.  Via Renato Vieira.

Anderson, Michael L.. 2014. "Subways, Strikes, and Slowdowns: The Impacts of Public Transit on Traffic Congestion." American Economic Review, 104(9): 2763-96.

Public transit accounts for 1 percent of U.S. passenger miles traveled but attracts strong public support. Using a simple choice model, we predict that transit riders are likely to be individuals who commute along routes with severe roadway delays. These individuals' choices thus have high marginal impacts on congestion. We test this prediction with data from a strike in 2003 by Los Angeles transit workers. Estimating a regression discontinuity design, we find that average highway delay increases 47 percent when transit service ceases. We find that the net benefits of transit systems appear to be much larger than previously believed.

Despite this really interesting finding, I just would like to note that the main purpose of public transport is not to reduce congestion, as many politicians and the general media like to think. The purpose of public transport  is to help people to access activities and opportunities. Although this might sound a subtle difference for some people, this difference has serious implications for how one should plan and evaluate transport policies.

Sunday, October 23, 2016

Urban Picture

Chicago towers over lake Michigan
by Nick Ulivieri (2016)

Thursday, October 20, 2016

PhD feelings

This is how doing a PhD feels like. I'm the clumsy flying fish

Tuesday, October 18, 2016

Quote of the Day: Bureaucracy

Saturday, October 15, 2016

Visualizing the space-time geography of flow data

Till Nagel and Christopher Pietsch have created an art installation that allows one to visualize and compare the spaces of flow created by bike-sharing systems in New York City, Berlin, and London. The name of the project is city flow, a comparative visualization environment of urban bike mobility. They have recently published a paper (co-authored with Marian Dörk) with more technical information about their project.

These guys are doing a fabulous work with design, and I believe they're really pushing the boundary of data visualization in urban and transport studies with new tools to visualize the space-time geography of flow data. 

Take a look at how easy it gets to explore trajectories of cyclists in space and time with their tool.

Tuesday, October 11, 2016

Cycle infrastructure is democracy in motion

A picture is worth a thousand words:

Sunday, October 9, 2016

The Social Fabric of Cities

Vinicus Netto (Twitter) has published a new book called 'The Social Fabric of Cities' (contents and introduction available here). This one is going straight to my reading pile and I'm sure it will be of interest for all the 100 million readers of this blog. Here are the foreword by Mike Batty and a description of the book.


"Linking the physical to the social city is the challenge of our times. This is one of the first attempts to systematically do so, and Netto brilliantly succeeds in showing how encounters, segregation, movement and interaction are reflected in our understanding of the form and function of the city." (Michael Batty, CASA, UCL)

Book description:

Bringing together ideas from the fields of sociology, economics, human geography, ethics, political and communications theory, this book deals with some key subjects in urban design: the multidimensional effects of the spatial form of cities, ways of appropriating urban space, and the different material factors involved in the emergence of social life. It puts forward an innovative conceptual framework to reconsider some fundamental features of city-making as a social process: the place of cities in encounters and communications, in the randomness of events and in the repetition of activities that characterise societies. In doing so, it provides fresh analytical tools and theoretical insights to help advance our understanding of the networks of causalities, contingencies and contexts involved in practices of city-making. 
In a systematic attempt to bring urban analysis and research from the social sciences together, the book is organised around three vital yet relatively neglected dimensions in the social and material shaping of cities: (i) Cities as systems of encounter: an approach to urban segregation as segregated networks; (ii) Cities as systems of communication: a view of shared spaces as a means to association and social experience; (iii) Cities as systems of material interaction: explorations on urban form as an effect of interactivity, and interactivity as an effect of form.

Friday, October 7, 2016

Urban Picture

Times Square, NYC, 1903
credit: ?