Beyond Roads: How Urban Planning Impacts Traffic Congestion
Traffic congestion is not merely a result of road capacity, but a direct consequence of how cities are planned, constructed, and utilized. A comprehensive study comparing 30 major cities worldwide reveals that urban design plays a pivotal role in whether traffic flows or stalls.
The research, conducted by ETH Zurich and the University of Wisconsin and published in Nature Communications, suggests that understanding the link between mobility and urban structure is the only way to design sustainable urban centers.
“Our cities are becoming increasingly complex, while transport systems are under ever mounting pressure,” says Yatao Zhang, the study’s first author. “the relationship between mobility and cities, as This represents the only way to develop and design urban centers sustainably.”
The Science of Urban Flow
To uncover these relationships, researchers analysed road traffic and congestion using data from Here Technologies, which monitors vehicle movements every five minutes. In Los Angeles, for instance, the study examined congestion values across more than 18,000 road sections.
The team correlated this congestion data with city characteristics sourced from Open Street Map. They looked at the structure of road networks, the shape of districts and green spaces, and the specific functions of urban areas, such as education, administration, shopping, sport, and housing.
Beyond the Asphalt
While road infrastructure is a known factor, the study found that the spatial arrangement of a city and its building types are equally determining. A sprawling city layout typically leads to increased traffic volumes.
Conversely, mixed-utilization areas—where living and working spaces coexist—tend to result in less traffic by shortening the distances people must commute. Zhang notes that “traffic is created by what people do, not just by the existence of roads.”
The research also identified that the accumulation of leisure activities in specific neighborhoods can drive an increase in traffic during weekends.
Global Comparisons and Future Planning
The study highlighted stark differences between global hubs. In Singapore, demarcated residential areas facing a center of service jobs mean that structural changes in housing areas directly impact commuter flows.
In contrast, this link is less pronounced in Zurich, where apartments are spread more evenly across the city. This suggests that the impact of urban development on transport varies significantly based on the city’s existing fabric.
Martin Raubal, Professor of Geoinformation Engineering at ETH Zurich, believes this new method could transform urban planning in the medium term. He states the study allows for predicting how a specific change, such as building a large shopping center, may impact traffic.
While the method offers a way to understand how transport policy measures work over the long term, Raubal notes that further detailed analyses are required before it can be implemented for planning in Zurich or other cities.
Frequently Asked Questions
What factors beyond road networks contribute to traffic jams?
Traffic is influenced by the spatial arrangement of the city, the types of buildings present, and how urban areas are used. For example, sprawling layouts increase traffic, while mixed-use areas (combining living and working) tend to reduce it.
How was the study conducted?
Researchers compared 30 major cities using vehicle movement data from Here Technologies and city characteristic data from Open Street Map, correlating congestion with features like green spaces, road junctions, and urban functions.
What is the difference between traffic patterns in Singapore and Zurich?
In Singapore, demarcated residential areas create a direct link between residential structural changes and commuter flows. In Zurich, because apartments are spread across the entire city, this link is much less pronounced.
How do you think your own neighborhood’s layout affects your daily stress and travel time?