Michael Szell
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mszll.datasci.social.ap.brid.gy
Michael Szell
@mszll.datasci.social.ap.brid.gy
430 followers 14 following 150 posts
Human-centric urban #DataScience 🚶🚲 Sustainable #mobility #networks, in #Copenhagen. searchable

Created: https://datasci.social, https://growbike.net […]

🌉 bridged from ⁂ https://datasci.social/@mszll, follow @ap.brid.gy to interact
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mszll.datasci.social.ap.brid.gy
Very cool paper out by our collaborator Chris Larkin (et al): Identification of plausible low traffic neighbourhoods using open data
https://www.sciencedirect.com/science/article/pii/S2950105925000415

Code: https://github.com/Froguin99/LTN-Detection
Map of Newcastle Upon Tyne, partitioned into potential low traffic neighborhoods
October 27, 2025 at 7:05 PM
mszll.datasci.social.ap.brid.gy
Here the city's press release: https://via.ritzau.dk/pressemeddelelse/14560655/line-barfod-om-kobenhavnsk-budget-stolt-af-det-storste-cykelbudget-nogensinde

They ~quadrupled the bicycle budget to >600 mio. DKK. Below my full comments to the journalist, which was used for the article.
Kilde: Mobilitetsredegørelsen 2025 På cykelområdet er der ca. blevet bevilliget 160 mio. kr. årligt (10-års gennemsnit for 2016-2025). Investeringer på cykelområdet omfatter både midler til cykelinfrastruktur og cykelinitiativer, men også sikre skoleveje, trafiksikkerhed samt eksterne investeringer og bidrag fra puljer. I 2025 blev der bevilliget 174 mio. kr. til cykelområdet. Af de 174 mio. kr. blev 82 mio. kr. bevilliget primær til cykelinfrastruktur og cykelinitiativer, 68 mio. kr. til sikre skoleveje, trafiksikkerhed, strøggader, cykel- og gangbroer og 11 mio. kr. i forbindelse med eksterne investeringer fra trafikselskaber samt bidrag fra puljer. From an urban planning perspective it is very good and much needed that Copenhagen is increasing its bicycle budget. It is especially important that some of this investment will be allocated to child safety, as Copenhagen's transport policies have indeed neglected children. I personally experience this every morning through the terrifying traffic chaos on the street of my 7 year old daughter's school. As a consequence, Copenhagen has fallen behind several cities in Europe. Investing into cycling is increasing a city's livability, and also comes with massive economic benefits, especially to the public health system. We should however not forget, that still vehicular infrastructure receives a budget that is many times higher than cycling, so this bicycle budget is only like a drop in the bucket. Despite the laudable efforts, Copenhagen is still missing the political will to boldly transform its transport system towards becoming truly human-centric. Also the public wants this, as one can see clearly in Paris' ongoing success story. So, despite offering fantastic cycling infrastructure for fit adults, Copenhagen unfortunately remains inherently car-centric. A budget increase is great, but not enough by far - it will need a fundamental rethinking of transport, urban living, and crucially the political will to change this.
October 17, 2025 at 11:44 AM
mszll.datasci.social.ap.brid.gy
Copenhagen increased its bicycle budget - I was asked to comment: https://www.verdensmaal.org/nyheder/k%C3%B8benhavns-kommune-vil-g%C3%B8re-det-lettere-at-suse-ge
Three cyclists riding in the foreground, colorful houses of Nyhavn harbor in the background
October 17, 2025 at 11:42 AM
mszll.datasci.social.ap.brid.gy
Nice project: A computational framework for quantifying route diversification in road networks
https://arxiv.org/abs/2510.02582

Interactive: https://divercitymaps.github.io/
Overview of DiverCity and global patterns in urban road networks. (a) Example of a trip with low DiverCity (2.18) in Mumbai. Near-shortest routes significantly overlap, leading to low route diversity. (b) Example of a trip with high DiverCity (9) in Tokyo, characterized by multiple spatially diverse near-shortest routes. For panels (a) and (b), inset bar plots show the travel time of each alternative route, with NSRs in blue and non-feasible routes (exceeding the near-shortest threshold, shown as a dashed line) in red.
October 6, 2025 at 10:00 AM
mszll.datasci.social.ap.brid.gy
Putting cyclists in boxes: An analysis of the bike box
https://www.sciencedirect.com/science/article/pii/S2214367X25001620

Looks like bike boxes are not very useful, i.e. mostly used like in the image below (which means not being used as intended) - now confirmed by science
Image of a bike box with one cyclists in the top right corner
September 28, 2025 at 6:31 PM
mszll.datasci.social.ap.brid.gy
Causal evidence of racial and institutional biases in accessing paywalled articles and scientific data
https://arxiv.org/abs/2509.08299

Nice setup - one more reason why it's a good idea to not put papers behind paywalls or data behind "data available upon request"
Of all references coming from each country, the proportion of upon-request references (i.e., those made to papers with data available upon request). Brown and green hues represent countries whose proportion is lower and greater than the median value, respectively. Countries with fewer than 100 references made to the 91,000 papers in our dataset are excluded and colored in gray. Global distribution of the percentage of references that are made towards paywalled papers. Countries with a lower percentage are colored brown while countries with higher percentage are colored blue.
September 15, 2025 at 7:32 AM
mszll.datasci.social.ap.brid.gy
The Hitchhiker’s Guide to challenges in transport policy research: Towards ANSWERing questions regarding life, mobility, and everything
https://www.sciencedirect.com/science/article/pii/S0965856425002782

Looks interesting, and cool paper title! 🤓
Twenty major categories of transportation policy publications.
September 15, 2025 at 6:30 AM
mszll.datasci.social.ap.brid.gy
If I was still working on signed networks, I might look into this one 😅
Network of deals and lawsuits with AI companies
September 8, 2025 at 7:07 AM
mszll.datasci.social.ap.brid.gy
Very interesting looking paper: In tech we trust: A history of technophilia in the Intergovernmental Panel on Climate Change's (IPCC) climate mitigation expertise
https://www.sciencedirect.com/science/article/pii/S2214629625003615

Hopefully someone will also […]

[Original post on datasci.social]
Frequency per page of selected terms related to key mitigation strategies in the six full reports of IPCC Working Group III published between 1992 and 2022. The data highlights the overwhelming dominance of the term “technology”, particularly in the third and fourth assessment reports (2001 and 2007), where it peaked at over 1.5 mentions per page. In contrast, demand-side concepts such as “lifestyle”, “behavioural change”, and “sufficiency” remained marginal until a notable increase in the 2022 report, reflecting a shift in discourse. Nevertheless, references to technological change continue to outnumber demand-side options by a factor seven.
September 6, 2025 at 6:10 PM
mszll.datasci.social.ap.brid.gy
Decoupling geographical constraints from human mobility
https://www.nature.com/articles/s41562-025-02282-7

Finally out, very cool work, congrats to the authors @Louis @benfmaier @suneman!
(Preprint: https://arxiv.org/abs/2405.08746v1 )
Illustration of the influence of geography on human mobility, (a) spatial arrangement of concentric circles of locations, (b) distance distribution of points to center of the disk (white cross). (c) Pair distribution of the points in the concentric circles, (d) simulated moving distance distribution for different cost of distance. Examples of more shapes and distributions of locations are studied in SI. 6.1. (e,f,g) Three geographies: (e) Real Denmark with 3.3M addresses, (f) Disk Denmark, where the macro structure has cities distributed uniformly at random on a disk, but the microstructure of the cities is preserved, and (g) Uniform Denmark with the macro structure of Denmark (shape of landmasses and city positions) but no local microstructure, i.e. uniformly distributed locations within cities. (h) Pair distribution of the three geographies, and (i) the simulated observed moving distance for an intrinsic distance cost of 1/r. In (h) and (i), I, II, III respectively represent the intra-city scale, the city scale, and the inter-city scale.
September 4, 2025 at 9:20 AM
mszll.datasci.social.ap.brid.gy
Countrywide natural experiment links built environment to physical activity
https://www.nature.com/articles/s41586-025-09321-3
Fig. 1: Physical activity levels undergo significant changes following relocation between US cities of different walkability levels.
August 15, 2025 at 3:25 PM
mszll.datasci.social.ap.brid.gy
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 👴
Researcher in red shirt presenting a poster, pointing to it
July 31, 2025 at 8:45 PM
mszll.datasci.social.ap.brid.gy
Claiming back space for people. Seen in Stockholm.
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.
July 26, 2025 at 5:00 PM
mszll.datasci.social.ap.brid.gy
Nice, clear division of research into Explanation vs. Prediction by Duncan Watts at #ic2s2
Speaker presenting in front of slide
July 24, 2025 at 7:29 AM
mszll.datasci.social.ap.brid.gy
My collaborator @bokanyie just gave a fantastic talk at #ic2s2 about our "urban highways" paper https://www.pnas.org/doi/10.1073/pnas.2408937122
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 .
July 22, 2025 at 12:49 PM
mszll.datasci.social.ap.brid.gy
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!
Photo of the Glan lake at sunset, sun shining through trees, red hut in forgetting
July 20, 2025 at 6:13 PM
mszll.datasci.social.ap.brid.gy
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]
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).
July 3, 2025 at 9:08 AM
mszll.datasci.social.ap.brid.gy
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]
Red book cover reading Compendium of Urban Complexity. Diego Rybski Editor. Springer
June 23, 2025 at 8:07 AM
mszll.datasci.social.ap.brid.gy
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.
Colorful lecture room with presenter in front of big screen showing a slide with stacked bar charts over time, titled "Topics in bicycle research".
June 5, 2025 at 6:50 AM
mszll.datasci.social.ap.brid.gy
..This doesn't make sense. I assume Paris counts 30km/h streets as protected bike infra? -would be questionable and redundant with the speed metric.👎

All in all, I think such reports are very important, to "name and shame" politicians for how much they are […]

[Original post on datasci.social]
Paris bicycle plan, downloaded from Open Paris data, created by Clement Sebastiao. The map shows green and red streets with implemented/planned protected bike infra. While this is a nice plan, this is a small part of the whole street network - MUCH less than 48%. (Hard to see here because streets are white and not all shown)
May 17, 2025 at 7:56 PM
mszll.datasci.social.ap.brid.gy
It hurts especially when politicians miss opportunities and behave like religious extremists (car=holy) at your front door. Here, in #frederiksberg, retaining ~30 SUV-size parking lots and the entrance from a main road, instead of opening the street to people. :eyebags: #welcometo1960
Photograph of a newly asphalted side street ending on a main road, showing many empty parking lots, taking away pedestrian and living space, soon to be filled up with parked SUVs
April 30, 2025 at 2:36 PM
mszll.datasci.social.ap.brid.gy
We also consider two European cities (Madrid, Barcelona) for less grid-like structures. Finally, we also show how different mapped network geometries can have an impact on CoolWalkability, so having good and adequate underlying data is important.
Network geometry can have an impact on CoolWalkability. Considering centerline versus the full pedestrian networks can lead to different results, as links in these networks are sometimes mapped differently in OpenStreetMap. Left map: A centerline-based mapping in Barcelona can inaccurately reflect the actual position of sidewalks. Right map: The full pedestrian links in the same area are mapped with more detailed geometries, some of them closer to buildings and therefore shaded, which comes with more flexibility for shaded routing when walking. Middle: Accordingly, the diurnal profiles in the centerline and full networks can differ substantially, especially for high sun avoidance alpha: Full networks generally display higher CoolWalkability and are more likely to have two dips.
April 29, 2025 at 12:06 PM
mszll.datasci.social.ap.brid.gy
We disentangle the effects of building heights and grid imperfections, showing that variations in street geometry and building heights create benefits for shade-seeking pedestrians.
Disentangling the effects of building height distribution and street geometry on Coolwalkability. Multiple curves shown in diurnal profiles correspond to different sun avoidance values – the curves mostly overlap, showing independence of Coolwalkability from , as proven analytically for the grid. All diurnal profiles shown for 2023-06-21. (A) Left: Zoom into Manhattan’s building footprints. Right: diurnal Coolwalkability profile. (B) Left: Zoom into Manhattan’s building footprints at constant height, set as the average 71m of empirical building heights. Right: The corresponding diurnal Coolwalkability profile. Due to loss of building height heterogeneity, the Manhattanhenge dips are slightly less pointy. (C) Right: Zoom into the grid with empirical building footprints taken from Manhattan. Left: the corresponding diurnal Coolwalkability profile. Keeping building height heterogeneity but changing from empirical street network to grid implies only slight differences in diurnal Coolwalkability. (D) Right: Zoom into the grid’s building footprints at constant height, set as the average 71m of empirical building heights. Left: the corresponding diurnal Coolwalkability profile. Due to loss of building height heterogeneity and the change to a grid, the Manhattanhenge dips are considerably broader and less pointy.
April 29, 2025 at 12:03 PM
mszll.datasci.social.ap.brid.gy
We define the CoolWalkability metric C(t), which measures the potential for shaded walks. We visualize this in the diurnal Coolwalkability profile, showing for Manhattan two dips: the typical "Manhattanhenges" for grid-like street networks.
Comparing CoolWalkability of Manhattan with a synthetic grid shows similarities but also crucial differences. (A) We introduce the diurnal Coolwalkability profile (here shown for 2023-06-21, and alpha=1.5). It shows two characteristic dips for Manhattan (green) due to the two Manhattanhenge events MH1 and MH2 at 11:05 and 13:25, respectively, where the sun is aligned with the grid. The dips are also present in the synthetic grid (grey), but less pointed. (B) We introduce the diurnal CoolWalkability phase portrait. It shows CoolWalkability versus shadow fraction, as functions of time, revealing larger differences. Manhattan’s portrait (green) is relatively smooth due to slight imperfections in its grid structure and heterogeneous building heights, while the grid’s portrait (grey) jumps discontinuously due to its perfect symmetries and constant building heights. The grid’s analytical solution of Manhattanhenges (black crosses) fits well with the numerical simulation. (C) Illustration of the two Manhattanhenge events MH1 and MH2 for Manhattan and the synthetic grid. Grey polygons denote building footprints, black polygons their shadows, orange arrows the direction of sun rays. Photograph of a Manhattanhenge: Sun on the horizon, shining on street between skyscrapers.
April 29, 2025 at 12:02 PM
mszll.datasci.social.ap.brid.gy
🎉 New paper out: CoolWalks for active mobility in urban street networks
https://www.nature.com/articles/s41598-025-97200-2

We study the potential for shaded walking, using building footprints and street networks.
Higher sun avoidance alpha implies choice of routes that are not physically shortest but that minimize experienced length. (A) 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). (B) The choice of which link to take depends on the pedestrian’s sun avoidance alpha. Increasing sun avoidance increases the experienced length because walking in the sun becomes less tolerable. At the threshold between different regimes, for example 1 (blue) to 2 (orange), the experienced length of the shaded link 2 becomes shorter than the experienced length of sunny link 1, implying a preference for link 2 despite longer physical length (dashed orange line). (C,D) Generalization from links to shortest paths with an example of five routes.
April 29, 2025 at 11:58 AM