Cities should focus on locating housing development close to city centres and workplaces in order to tackle transport-related emissions, a new study by the Potsdam Institute for Climate Impact Research has suggested.
According to the study, which was published in the Environmental Research Letters journal and undertaken in collaboration with the University of California, Berkeley, the University of Sussex and other partners, well-targeted building densification can become a ‘critical lever’ for urban planners in addressing transport emissions.
The study analysed 10 million mobility data points from cities including Berlin, Boston, Los Angeles, Rio de Janeiro and Bogotá, to examine how urban layouts influence how citizens commute to work, and the associated emissions from said transport.
‘Urban interdependencies’
“Our model reveals the actual interdependencies between various urban factors even before we determine their specific effects,” commented Felix Wagner, who completed his PhD at PIK in 2025 and led the study as part of his doctoral research.
“This fundamentally changes the recommendations that can be responsibly given to planners. Distances to city centres and working places are key. And urban densification cannot be viewed in isolation: one must understand how urban density relates to secondary factors such as connectivity, accessibility and the choice of residential location.”
As the study found, in monocentric metropolitan regions such as Berlin and Boston, the most valuable sites for infill development are neighbourhoods located in a ring around the centre – in Boston, this would extend to between 10 and 21 kilometres from the city centre, while in Rio de Janeiro, it would stretch up to 40 kilometres outwards from the centre.
In the case of polycentric cities such as Los Angeles and the San Francisco Bay Area, the study found that emissions reductions can be more effectively achieved through increased development around clusters of employment opportunities rather than a single central core.
‘Spatial specificity’
“Urban planning experts often discuss densification as a one-size-fits-all policy that is either implemented or not,” added PIK researcher Felix Creutzig, a co-author of the study. “However, our data show that a single measure can significantly shorten commuting distances in one neighbourhood, yet have little effect two kilometres away. This spatial specificity has been missing until now.”
The study, titled Refining urban typologies: Causal insights into urban form, car commuting, and related CO₂ emissions, was produced as part of the CircEUlar project, funded by the European Union’s Horizon Europe programme. Read more here.
