Using Game Theory to Make City Streets Safer
20 years ago, a radical experiment was announced in seven cities across Europe: They would flatten sidewalks, remove traffic signs and painted road markings, and take down traffic lights. It was part of an E.U.-funded project designed to test how to make streets safer for all users—drivers, cyclists, and pedestrians.4
In fact, 20 years on, some of these cities still adhere to this principle of “less is more” to improve safety. How can this be?
How can game theory explain traffic patterns?
Countries have many forms of signage for safe travel. Germany, for example, has 648 different traffic signs.15 Surely this contributes to the reason why something as anarchic as the speed-limit-free Autobahn can produce fewer traffic fatalities than a Canadian highway?10
In fact, the evidence suggests street signage can make more a place more dangerous, not less. To explain why, we can look to game theory.
Game theory is the scientific study of how, when, and why people cooperate (and don’t cooperate). It comes from mathematics but has been applied extensively in economics and the social sciences (e.g. the prisoner’s dilemma), and even used as a call-to-arms by environmentalists.20 It has been invoked to explain why some people are altruistic donors, and how residency students are matched to hospitals.21
Game theory very simply explains how human decision-making in many realms depends on interactions with other people in the environment—like what we would find in the artificially-controlled environment of a board game.
A “game” in game theory is a situation “in which decision-makers interact with one another, and in which the happiness of each participant with the outcome depends not just on his or her own decision but on the decisions made by everyone.”3 Driving is therefore game-like by definition. The speed, safety, and enjoyment of driving depends greatly on the other drivers (or cyclists or pedestrians) on the road. Your actions depend on how those actors react, drive, walk, or cycle.
Driving requires cooperation. We drive how and where we want, but we adhere to rules that help coordinate our actions, as in a complex game. For example, you can drive through a green light without stopping because you are cooperating with the car at the adjacent red light. They pay a cost in time, so that you can continue accident-free.2 Our cooperative behavior with other drivers happens mostly unconsciously, as we assume a mutual agreement to stick to the rules of the road.
If we assume we understand the rules of the road equally, why then are traffic accidents still so common? In Berlin, for example, there is a car accident every 4 minutes.14 The majority of accidents producing injury (both minor or severe) happen at intersections.17
How could removing the stop sign at an intersection improve our driving safety?
References
- Cohen, E. (2013). Segregated bike lanes are safest for cyclists. CMAJ, 185(10). https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3708009/
- Cortés-Berrueco, L. E., Gershenson, C. & Stephens, C. R. (2016). Traffic Games: Modeling Freeway Traffic with Game Theory. PLOS One https://doi.org/10.1371/journal.pone.0165381
- Easley, D. & Kleinberg, J. (2010). Chapter 8: Modeling Network Traffic using Game Theory. In, Networks, Crowds, and Markets: Reasoning about a Highly Connected World (pp. 232). Cambridge University Press. https://www.cs.cornell.edu/home/kleinber/networks-book/networks-book-ch06.pdf
- European Union. (2020). Shared Space: Reconciling People, Places and Transport. https://keep.eu/projects/307/
- Evening Standard. (2008, June 23). Accident-free zone: The German town which scrapped all traffic lights and road signs. Evening Standard. https://www.standard.co.uk/news/accident-free-zone-the-german-town-which-scrapped-all-traffic-lights-and-road-signs-6932977.html
- Evgenikos, P., Yannis, G., Folla, K., Bauer, R., Machata, K., Brandstaetter, C. (2016). How Safe are Cyclists on European Roads? Transportation Research Procedia, 14, 2372-2381. https://doi.org/10.1016/j.trpro.2016.05.269
- Ipswich Star. (2012, November 4). Shared space still controversial topic. Ipswich Star. https://www.ipswichstar.co.uk/news/shared-space-still-controversial-topic-1-1678977
- Jackson, E. (2019, August 29). Congestion is only getting worse and it turns out you (yes, you!) are a big part of the problem. The Financial Post. https://financialpost.com/transportation/congestion-is-only-getting-worse-and-it-turns-out-you-yes-you-are-a-big-part-of-the-problem
- Morton, B. (2020, June 27). “Coronavirus: Will pop-up bike lanes keep new cyclists on the road.” BBC. https://www.bbc.com/news/uk-53105020
- OECD. (2019). Road accidents. https://data.oecd.org/transport/road-accidents.html
- Oltermann, P. (2020, August 4). Berlin reports rise in fatalities as new bike lanes fail to keep cyclists safe. The Guardian. https://www.theguardian.com/world/2020/aug/24/berlin-reports-rise-in-fatalities-as-new-bike-lanes-fail-to-keep-cyclists-safe
- Portor, M. (2018, January 18). Was wäre, wenn es keine Straßenschilder mehr gäbe? Mobility Mag. https://mobilitymag.de/shared-space-strassen-ohne-schilder/
- Pratelli, A. (2006). Design of modern roundabouts in urban traffic systems. Conference paper from Urban Transport 2006. 10.2495/UT060091
- RBB. (2020, February 24). Alle vier Minuten kracht es in Berlin. RBB.https://www.rbb24.de/panorama/beitrag/2020/02/2019-gab-es-147-000-verkehrsunfaelle-in-berlin.html
- Schulz, M. (2006, November 16). European Cities Do Away with Traffic Signs. Der Spiegel. https://www.spiegel.de/international/spiegel/controlled-chaos-european-cities-do-away-with-traffic-signs-a-448747.html
- Stone, J. (2020, July 13). Pop-up cycle lanes across London could be made permanent after pandemic, says transport boss. The Independant. https://www.independent.co.uk/news/uk/politics/cycle-lanes-london-pop-kept-after-pandemic-a9616041.html
- Drößiger, J., Kostrzynski, M., Lehmann, H., Meidinger, D., Wittlich., H. (2020, July 28). Tagespiegel. https://interaktiv.tagesspiegel.de/lab/alle-schlimmen-verkehrsunfaelle-in-berlin-auf-einer-karte/
- The Local. (2019, Febuary 1). Are Germany’s autobahns really the safest highways in the world? The Local. https://www.thelocal.de/20190201/are-germanys-autobahns-really-the-safest-highways-in-the-world
- The Local. (2020, September 8). Why a court says Berlin’s new pop-up bike lanes must be scrapped. The Local. https://www.thelocal.de/20200908/why-a-court-says-berlins-new-pop-up-bikes-lanes-must-be-scrapped
- Hardin, G. (1968). The tragedy of the commons. Science, 162(3859). https://science.sciencemag.org/content/162/3859/1243
- Maaz, M. (2020). A primer on the game theory behind the national resident matching program for the medical educator and student. Medical Science Educator, 30(2), 965-969. https://doi.org/10.1007/s40670-020-00955-8
About the Author
Natasha Hawryluk
Natasha is a consultant in change management and organization design. During her psychology undergrad, Natasha assisted in a fMRI lab and intercultural communication lab at the University of Alberta. Natasha's psychology background and exposure to behavioral science during graduate school influenced her to continue to engage her passion for understanding human behavior even in her industry-facing career. Natasha lives in Berlin,Germany where she completed her MBA ('18).
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