Key takeaways
- Researchers from UCLA and Google conducted the most comprehensive global study of active transportation to date, analyzing travel patterns in more than 11,500 cities representing roughly 41% of the world's urban population.
- Expanding city-level walking and cycling infrastructure globally could cut carbon emissions by 6% and generate $435 billion in health benefits annually.
- Increasing density and redesigning streets to make active travel safer and more comfortable are the two most effective ways cities can encourage more people to walk and bike.
A new study published in the Proceedings of the National Academy of Sciences reveals the transformative potential of walking- and cycling-friendly policies in cities around the world. Conducted by researchers from UCLA and Google, the study analyzed travel data from more than 11,500 cities across 121 countries, making it the most comprehensive global assessment to date of active transportation, or the potential for walking or biking.
The findings show that increasing density and redesigning streets to make active travel safer and more comfortable are the strongest predictors of high walking and biking rates. If every city expanded its bike lane network and redesigned streets to match Copenhagen, Denmark, global walking and biking rates would increase by 412 billion miles, or 663 billion kilometers, per year — leading to an estimated 6% reduction in global carbon emissions and $435 million in health benefits. These policies to promote walking and biking can also reduce road traffic deaths, air pollution and road user stress.
Adam Millard-Ball, lead author and director of the UCLA Institute of Transportation Studies, highlighted how local planning decisions shape how people travel. "The way that cities design their streets fundamentally shapes how people get around, especially for short trips. Are there sidewalks? Bike lanes? How wide are the traffic lanes?" Millard-Ball said. "In this study, we show that these seemingly local planning choices, made in thousands of cities around the world, can collectively drive major shifts in global climate outcomes."
Greenhouse gas benefits of bicycle facilities
This research from the UCLA transportation institute and Google marks a major leap forward in understanding active travel patterns around the world. It is the first to provide globally consistent data analysis across a diverse range of city sizes, income levels and geographies. With more than 14 times as many cities as the next largest study, the dataset represents an estimated 41% of the world's urban population — offering unprecedented insight into how urban form and local policy shape walking and biking worldwide.
The study leverages data from Google's Environmental Insights Explorer, which uses aggregated and anonymized location history data from opted-in users. EIE allowed the researchers to identify the number and mode of trips, along with distance traveled by each mode within a given city.
To help translate these research insights into actionable strategies for safer cities, the research team also released a companion playbook for city leaders and transportation planners. The playbook distills key findings from the study into data-driven recommendations, paired with case studies from eight successful cities around the world.
Each case study highlights specific policy initiatives that have led to remarkably high shares of walking and cycling. More importantly, they illustrate that there is no one-size-fits-all approach and that successful active transportation infrastructure is not confined to one city or one region.
The approach enabled researchers to analyze walking and cycling patterns in regions historically underrepresented in English-language transportation research — including Latin America, South Asia, Japan and Sub-Saharan Africa.
In Nairobi, Kenya, for example, informal traders have participated in the design process for pedestrian improvements, and the city commits at least 20% of the transportation budget to non-motorized transportation. In Osaka, Japan, narrow streets and slow-moving traffic highlight the ways in which more informal pedestrian and cyclist infrastructure can be just as effective in encouraging walking and biking as the formal networks seen in Copenhagen and Amsterdam.
Expanding the list of top walking- and cycling-friendly cities revealed another key insight: Weather does not have a major impact on active travel. Some of the highest rates of active travel are found in the snow of Montreal and Copenhagen, and in the heat and humidity of Kolkata, India, and Dhaka, Bangladesh. This significantly broadens the possibilities for cities located in areas with harsher winters or summers to invest in pedestrian and cycling infrastructure and policies.
"Copenhagen and Amsterdam rightfully get a lot of attention for their world-class street designs that put pedestrians and bicycle riders first. But they're not the only success stories," Millard-Ball said. "Cities like Osaka, Buenos Aires, and Nairobi have taken very different paths — and still achieved impressive results."
"The lesson is clear: You don't need to replicate Copenhagen to make your city walkable and bike-friendly."
