The research was led by Yatao Zhang of ETH Zurich and the University of Wisconsin and appears in Nature Communications. Zhang based the work on his doctoral thesis, completed in the autumn of 2025 at the Singapore‑ETH Centre. The team compared 30 major cities, including Zurich, and focused on road traffic and congestion.
They used vehicle movement data from Here Technologies with a five‑minute time resolution; for Los Angeles the study included congestion values for more than 18,000 road sections. City characteristics came mainly from OpenStreetMap, covering road networks, traffic junctions, green spaces and the function of urban areas like housing, shopping, sport, administration and education. The scientists correlated these features with congestion data.
The team developed a new method to analyse how urban features and traffic influence one another over time, revealing cause‑and‑effect links. Results confirm a strong link between road network expansion and traffic, and show that city form and building functions affect traffic volumes. For example, sprawling cities tend to produce more traffic, clusters of leisure increase weekend traffic, and mixed‑use areas reduce commuting distances. The comparison also highlights city differences: in Singapore changes in housing affect commuter flows, while in Zurich the link is less pronounced. Martin Raubal, a supervisor of the study, says the method can predict how a change such as a large shopping centre will affect traffic in the medium term, but further detailed analyses are needed before using it for local planning.
Difficult words
- congestion — heavy traffic and slow movement on roadscongestion values
- correlate — show a relationship between two thingscorrelated
- sprawling — with buildings and roads spread over large area
- commute — travel regularly between home and workplacecommuting
- mixed‑use — areas with homes, shops and workplaces togethermixed‑use areas
- predict — say what will happen in the future
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- How might a new large shopping centre change traffic in your city? Give one example.
- What are the advantages of mixed‑use areas for people who travel to work?
- Why do you think sprawling cities produce more traffic than compact cities?
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