Michael Szell

Car culture at its absolute worst meets an unjust legal system. Parents lose a son and are then convicted of a felony because they let him walk across the street. Gift link […]

You Can't Just "Control" For Things Statistical control usually doesn't make an analysis causal and it can easily mislead

You Can't Just "Control" For Things

"Statistical control usually doesn't make an analysis causal and it can easily mislead"

https://www.cremieux.xyz/p/you-cant-just-control-for-things

clear, rapid introduction to key issues

Long-term exposure to outdoor air pollution linked to increased risk of dementia - MRC Epidemiology Unit An analysis of studies incorporating data from almost 30 million people has highlighted the role that air pollution – including that coming from car exhaust emissions – plays in increased […]

Long-term air pollution exposure and incident dementia: a systematic review and meta-analysis
https://www.thelancet.com/journals/lanplh/article/PIIS2542-5196(25)00118-4/fulltext

https://www.mrc-epid.cam.ac.uk/blog/2025/07/25/long-term-exposure-air-pollution-dementia/

Street network sub-patterns and travel mode Urban morphology has long been recognized as a factor shaping human mobility, yet comparative and formal classifications of urban form across metropolitan areas remain limited. Building on theoretical principles of urban structure and advances in unsupervised learning, we systematically classified the built environment of nine U.S. metropolitan areas using structural indicators such as density, connectivity, and spatial configuration. The resulting morphological types were linked to mobility patterns through descriptive statistics, marginal effects estimation, and post hoc statistical testing. Here we show that distinct urban forms are systematically associated with different mobility behaviors, such as reticular morphologies being linked to significantly higher public transport use (marginal effect = 0.49) and reduced car dependence (-0.41), while organic forms are associated with increased car usage (0.44), and substantial declines in public transport (-0.47) and active mobility (-0.30). These effects are statistically robust (p < 1e-19), highlighting that the spatial configuration of urban areas plays a fundamental role in shaping transportation choices. Our findings extend previous work by offering a reproducible framework for classifying urban form and demonstrate the added value of morphological analysis in comparative urban research. These results suggest that urban form should be treated as a key variable in mobility planning and provide empirical support for incorporating spatial typologies into sustainable urban policy design.

Street network sub-patterns and travel mode
https://arxiv.org/abs/2507.19648

Researcher in red shirt presenting a poster, pointing to it

Back from #ic2s2 which was again a fantastic conference experience - congrats to the organizers! Some professors got a poster this time, which was actually super fun to design and present - haven't done it since my 1st year of PhD 16 years ago 👴

Upcoming special issue in Urban Planning (cogitatio): Citizen-Centric Urban Planning Through Participatory Sensing Data and Digital Tools
https://www.cogitatiopress.com/urbanplanning/issue/futureissues#i530
Abstract submission deadline in December.

All main "international" conferences in 3 fields related to my research (netsci, icssi, ic2s2) announced 2026 to be held in an authoritarian country, without any questioning. What does this say about these fields and their decision structures? 🤔

Photo of five lanes. Left for pedestrians. Second also for pedestrians, but was previously a protected bike lane. Third a previous car lane, now a protected bike lane. Fourth the single left car lane. Fifth bus lane.

Claiming back space for people. Seen in Stockholm.

Speaker presenting in front of slide

Nice, clear division of research into Explanation vs. Prediction by Duncan Watts at #ic2s2

Seeing talk titles at #ic2s2 I can't be the only one, when reading LLM or AI, having to react with "oh, yet another one 🙄"? No disrespect to colleague's work, but the topic feels overhyped.. Not *everything* needs an LLM angle. #grinchmoment

Introducing the Heart Foundation’s Community Walkability Map - Jake Coppinger I’m pleased to share the completion of a recent commercial engagement with the Heart Foundation: the Community Walkability Map, a new interactive tool designed to help communities understand and advocate for more walkable, healthier neighbourhoods.

@jakecoppinger is at it again with this very cool accessible walkability tool. This one is not just for the urbanism and transport nerds, so consider sharing it off this platform 😅

https://jakecoppinger.com/2025/06/introducing-the-heart-foundations-community-walkability-map/

Female researcher in front of speaker pult presenting. Slide in background.

Female researcher in front of speaker pult presenting. Slide in background. Black banner on the side reading IC2S2 .

My collaborator @bokanyie just gave a fantastic talk at #ic2s2 about our "urban highways" paper https://www.pnas.org/doi/10.1073/pnas.2408937122

Photo of the Glan lake at sunset, sun shining through trees, red hut in forgetting

If you have arrived in Norrköping for #ic2s2 and wonder if you should jump into the Glan then yes you absolutely should. Weather & water are fantastic!

Looking forward to #IC2S2 next week! On tuesday we'll have a talk on our "Urban highways" PNAS paper, and a poster (ID 94) on 3 bike network papers. See you there!

Mobilitätsforscher: "Private Autoabstellplätze dürfen nicht in der Stadt sein" Jetzt anhören: Hermann Knoflacher erklärt, warum das Auto für ihn ein "Virus" ist und was es braucht, damit Menschen in der Stadt und auf dem Land auf den Pkw verzichten

Neues Knoflacher Interview: https://www.derstandard.at/story/3000000274255/mobilitaetsforscher-private-autoabstellplaetze-duerfen-nicht-in-der-stadt-sein

Extracting Realistic Pedestrian, Cycling, and Driving Street Networks from OpenStreetMap
https://isprs-archives.copernicus.org/articles/XLVIII-4-W13-2025/103/2025/

Watching @notjustbikes videos and adding to my list of places in Europe to visit. This one is incredible, I spent the first few minutes thinking “I wish he hadn’t muted the ambient sound so people could realize how quiet a city without cars is”. Then I realized he didn’t! […]

Do Sports Utility Vehicles (SUVs) Cause More Severe Injuries to Pedestrians and Cyclists than Passenger Cars, in the Case of a Crash? Findings from Great Britain, 2004-2023 […]

Example of three different links connecting two nodes in the street network, from shortest and least shaded (1, blue) to longest and most shaded (3, green).

Probably a good day 🥵 to remind of our CoolWalks study: https://www.nature.com/articles/s41598-025-97200-2
- Above all, stop burning fossil fuels
- Buildings (and trees) cast a lot of shade in cities. We systematically quantify the benefits for 🚶🚴
- Make shade […]

[Original post on datasci.social]

#ICWSM25 is finally here!!!

Do not miss this out 👇👇👇
And see you tomorrow at the lunch special session 🚀

Red book cover reading Compendium of Urban Complexity. Diego Rybski Editor. Springer

Our chapter on Urban #mobility is finally published, in the great Compendium of Urban Complexity!
https://link.springer.com/chapter/10.1007/978-3-031-82666-5_4
pdf: http://michael.szell.net/downloads/alessandretti2025um.pdf

We explore the topic from […]

[Original post on datasci.social]

How to cooperate for a sustainable future? We don't know (yet), but I'm thrilled to share that our new perspective piece has just been published in @PNASNews. Bridging complexity science and multiagent reinforcement learning can lead to a much-needed science of collective, cooperative intelligence.

Interesting interview: Why a professor of fascism left the US: ‘The lesson of 1933 is – you get out’
https://www.theguardian.com/us-news/2025/jun/16/why-a-professor-of-fascism-left-the-us-the-lesson-of-1933-is-you-get-out

It is with great sadness that I am doing what I would once have thought unthinkable. Following Salim Abdool Karim's superb Faraday Lecture 10 days ago, i have decided to return my own Faraday prize, awarded in 2014.

The silence of the Royal Society in the face of Elon Musk's rampage (a member […]

Global health and climate benefits from walking and cycling infrastructure
https://www.pnas.org/doi/10.1073/pnas.2422334122
"If every city increased the extent of its bicycle network to the level of Copenhagen, Denmark, our simulations indicate reductions in private vehicle emissions of ~6% and […]

The cars are going to be alright: Examining micromobility infrastructure space allocation and potential improvement scenarios in Montréal
https://www.sciencedirect.com/science/article/pii/S2950105925000154

Network evolution analysis: a usage-centric approach applied on cycling infrastructure
http://204.48.17.207/index.php/josis/article/view/379

The "Gollum effect" - wow didn't know this name, but yes, this is exactly what makes certain fields so terrible (like network science). It's just about old men behaving like Gorillas 🤮 https://www.nature.com/articles/d41586-025-01588-w

It's so nice when PhD students can establish themselves […]

A nice article was just published in our Focus Issue on Urban Mobility and Green Transportation in Sustainable Cities:
Active travel modelling: a methodological approach to networks for walking and cycling commuting analysis
https://iopscience.iop.org/article/10.1088/2632-072X/add257

Colorful lecture room with presenter in front of big screen showing a slide with stacked bar charts over time, titled "Topics in bicycle research".

Here a nice overview on the last 30 years of bicycle research by Eva Heinen. There are always diverse topics, but a main focus has shifted from helmets to infrastructure and urban planning. Rightfully so.