Thursday, January 30, 2014

Accessibility Observatory + GTFS data

David Levinson, Andrew Owen and their team at the University of Minnesota have recently created the Accessibility Observatory. If you're interested in the topic, you may read a nice piece written by Emily Badger for TAC.

One of the greatest aspects of this project is about the data sources and methods they use for accessibility evaluation. Instead of relying on traditional household travel surveys, they combine open source data from OpenStreetMap (OSM) and from General Transit Feed Specification (GTFS), developed by Google. With this sort of data it is possible to analyze jointly the public transport system as a whole (routes, stops, and schedules) plus pedestrian routes and walking times. There is a more detailed explanation of how it works here

I've bee thinking a lot about this 'empirical strategy' since I'm planning to dedicate part of my PhD to research socio-spatial inequalities in the distribution of accessibility. The more I think about this, the more I become a passionate skeptic, more passionate than skeptic.

To be honest, I believe that these data/methods are probably not going to revolutionize accessibility research in transport studies. However, this new 'empirical strategy' allows us to expand accessibility analysis so as to incorporate hundreds of cities where no travel survey has been undertaken. It also provides a tool with great potential to compare accessibility levels across space and time and to assess how certain modifications in the public transport system can affect accessibility levels. Not to mention the research questions you could address by combining these data/methods with Census data.

By the way, the use of GTFS in accessibility analysis is quite new. I have found a few applications that have been using GTFS since 2010 but none seems to be as advanced the Accessibility Observatory at Minnesota. Here is a list with some of those other initiatives:

In 2013 we saw many more initiatives:

I must be missing some other initiatives and publications, so please leave a comment to this post with suggestions and links if you remember any.

[image credit: Transit Accessibility for the Minneapolis St. Paul region from the Accessibility Observatory]

Wednesday, January 29, 2014

Age related CO2 Emissions

This article provides a methodological contribution to the study of the effect of changes in population age structure on carbon dioxide (CO2) emissions. First, I propose a generalization of the IPAT equation to a multisector economy with an age-structured population and discuss the insights that can be obtained in the context of stable population theory. Second, I suggest a statistical model of household consumption as a function of household size and age structure to quantitatively evaluate the extent of economies of scale in consumption of energy-intensive goods, and to estimate age-specific profiles of consumption of energy-intensive goods and of CO2 emissions. Third, I offer an illustration of the methodologies using data for the United States. The analysis shows that per-capita CO2 emissions increase with age until the individual is in his or her 60s, and then emissions tend to decrease. Holding everything else constant, the expected change in U.S. population age distribution during the next four decades is likely to have a small, but noticeable, positive impact on CO2 emissions.

Thursday, January 23, 2014

Blog Updates

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Tuesday, January 21, 2014

Urban Picture

Apparently, this is Houston (via @transitized)

[image credit: ? ]

Soundtrack: Brazilian 'Jazz'

Sunday, January 19, 2014

Quote of the Day

"You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions." (Naguib Mahfouz)


Friday, January 17, 2014

off-topic: The truth behind British politeness

Being a Brazilian living in the UK, I am often surprised at how polite the British people can sound. The point is that I'm still struggling to read their real message between the lines.

The Telegraph have published something that might help: a translation table explaining the truth behind British politeness (ht Flavia Marreiro). Here are some of my favorites:

What the British say What Foreigners understand What the British mean
With the greatest respect He is listening to me  You are an idiot 
That's not bad That's poor  That's good
Quite good Quite good  A bit disappointing
I would suggest Think about the idea, but do what you like  Do it or be prepared to justify yourself
Very interesting They are impressed  That is clearly nonsense 
I almost agree He's not far from agreement  I don't agree at all
I only have a few minor comments He has found a few typos  Please rewrite completely 

And to be honest, we also have the Brazilian way of expressing ourselves: what Brazilians mean when they say

ps. image credit: LLKC at

Sunday, January 12, 2014

A Travel Time Map of the Roman Empire

A neat isochronic map! via Patrick Chovanec:

Travel times from Rome, at the time of the Roman Empire in number of days (each shade represents one week). This map is part of the The Stanford Geospatial Network Model of the Roman World. There is also a short video showing how to export data and to navigate the interactive maps of the projecet.

[image credit: orbis.stanford]

Related Links:

Higher education in BRIC countries: a demographic perspective

The future of higher education in BRIC countries: a demographic perspective. A new paper published by Raquel Guimarães in the Brazilian Journal of Population Studies (REBEP).

In regard to the development and reform of higher education (HE), recent and projected evidence suggest that enrollment growth is likely to be slower than it is at present (or even negative) as a result of ageing populations. The case of the BRIC countries is particularly interesting for the study of the impact of demographic changes on HE because these countries show considerable diversity regarding their demographic transition. This paper explores how demographic changes are likely to affect the demand for higher education in BRIC countries. I argue that these countries are now facing a great expansion of enrollment but, given declining fertility levels, diversification of the HE clientele will become a common strategy. But diversification of the student population will place a new and complex set of demands on HE institutions, and equity in higher education in the near future will depend on how HE systems are structured in these countries.

Related Links:

Wednesday, January 8, 2014

Urban Picture

[image credit: ? ]

[image credit: ? ]


[image credits: ? via]

Urban Policies and Public Space Allocation

A couple of months ago, I shared a post with a short presentation by Janette Sadik-Khan talking about the recent low-cost interventions on public space in NY City. The fact is that these interventions have been around for years now, and Clarence Eckerson and the team at Streetfilms have been documenting these changes since their early stages.

Here is one of their short films showing the remarkable before-and-after transformation of several streets and intersections in NY City. (via Sarah Goodyear):

What makes me particularly interested in such urban transformations is the way they make evident the idea that public space is a scarce resource in large cities. Though unnoticed by some policy makers, great cities face a clear resource dilemma in the allocation of public space in general and road space in central areas in particular. In some large cities like London, transport authorities have acknowledged this issue a long time ago.

Deciding upon who should have the priority to use urban space in certain areas of the city (drivers, cyclists, pedestrians and/or public transport users), however, is quite complex. These decisions are complex both because of the technical aspects in the construction of bike lanes, bus lanes and corridors, congestion charging schemes etc. and especially because of the public and political acceptability of such decisions (Banister, 1994).

In the way I like to read these 'urban interventions', they all come down to the role played by policy makers in mediating conflicts that arise from unjust/asymmetrical appropriation of space by individuals and social groups. And as in any other field of public policy, it is crucial to evaluate such urban policies in order to identify those types of interventions that work and to learn from those that do not work. I will probably dedicate more attention to this topic in my research, so hopefully I'll post more on this theme in the future.

Tuesday, January 7, 2014

Transport Controversies, TSU Seminars

In the next three months, the Transport Studies Unit (TSU) at the University of Oxford will be holding a series of seminars covering some Transport Controversies.

Professors like Henry Overman (LSE), Iain Doherty (University of Glasgow) and others will be discussing many interesting topics such as the the spatial implications of High Speed 2 and the distributional aspects of investments in transportinfrastructure.

The seminars are open to the public. Please, spread the words for those around.

Saturday, January 4, 2014

Delineating Geographical Regions with telephone call networks

An interesting paper discussing the delimitation of geographical regions and community boundaries, by Michael Szell and colleagues. This study can bring useful insights to the debate on functional urban areas and on the definition of metropolitan boundaries.

Sobolevsky S et al. (2013) Delineating Geographical Regions with Networks of Human Interactions in an Extensive Set of Countries. PLoS ONE 8(12): e81707. doi:10.1371/journal.pone.0081707


Large-scale networks of human interaction, in particular country-wide telephone call networks, can be used to redraw geographical maps by applying algorithms of topological community detection. The geographic projections of the emerging areas in a few recent studies on single regions have been suggested to share two distinct properties: first, they are cohesive, and second, they tend to closely follow socio-economic boundaries and are similar to existing political regions in size and number. Here we use an extended set of countries and clustering indices to quantify overlaps, providing ample additional evidence for these observations using phone data from countries of various scales across Europe, Asia, and Africa: France, the UK, Italy, Belgium, Portugal, Saudi Arabia, and Ivory Coast. In our analysis we use the known approach of partitioning country-wide networks, and an additional iterative partitioning of each of the first level communities into sub-communities, revealing that cohesiveness and matching of official regions can also be observed on a second level if spatial resolution of the data is high enough. The method has possible policy implications on the definition of the borderlines and sizes of administrative regions.

[image credit: Sobolevsky S et al., 2013]

Thursday, January 2, 2014

Message of the Day

Soundtrack: It's 2014 already. Welcome home my Dear!