Building Bicycle Lanes Like Those in Copenhagen in Cities Worldwide Could Save $435 Billion Annually in Health Costs

Active mobility, both walking and cycling, has very positive effects on every person’s health as it represents daily exercise. However, urban planning does not always consider this aspect, as many cities prioritize car travel—with large urban highways, narrow sidewalks, and no cycling space—over sustainable transport. A comprehensive study published this Monday in the scientific journal PNAS analyzes journeys in over 11,500 cities worldwide, providing more arguments for humanizing urban environments: building bike lanes following Copenhagen’s model could reduce emissions by about 6% and save up to $435 billion a year in health costs.

The study reviews anonymized travel modes conducted in 2023 across 11,587 cities in 121 countries and six continents, where around 2 billion people live (about 41% of the global population) and processes the data using a Bayesian hierarchical model, a statistical method that models data with many variables (such as climate, gasoline prices, GDP per capita, or average wages).

“The main conclusion of our study is that there are substantial health and climate benefits from redesigning streets with bike lanes. We estimate that an expansion of bike paths similar to Copenhagen levels would reduce private car emissions by about 6%” in the cities analyzed, explains Adam Millard-Ball, the lead author of the study, via email. “Secondly, climate is not an excuse, as cities with both warm and cold climates, and even those where it often rains or snows, also have significant levels of people walking or cycling. Thirdly, cities do not need to become Copenhagen or Amsterdam to succeed: there are numerous positive examples around the world, from Buenos Aires to Montreal and Osaka.”

Thus, the paper notes that the construction of each additional kilometer of bike lane is associated with approximately 13,400 additional kilometers of cycling trips. “Traffic danger is one of the main reasons people do not use bikes, and bike lanes can make it more comfortable and safe. Of course, not all bike lanes are the same: protected bike lanes are particularly effective, while those located in urban areas where a lot of people cycle and where driving and parking is difficult are the most likely to attract new users,” comments Millard-Ball.

He adds: “In almost all cities, there is significant latent demand: people want to bike, but they will not if the roads are too dangerous.” Additionally, they have found that cities with less gradient tend to have a higher proportion of cyclists, while other variables like gasoline prices also encourage more people to travel by bike or walk.

Another idea is to redesign streets so that active mobility—walking and cycling—becomes safer and more comfortable. “The design of streets—sidewalks, safe crossings, and traffic calming measures such as raised crossings—is important for active mobility,” the document states. These measures can enhance walkability, allowing more pedestrian movement, which also has broad health benefits and reduces emissions.

In Spain, there is much work to be done: a recent report by the Network of Walking Cities analyzed 950 streets from 85 Spanish cities and concluded that 68% of public space is dedicated to cars and only 32% is for pedestrians (who must share it with urban furniture, trees, and poorly parked vehicles), a figure that drops to 25% in urban periphery areas. Furthermore, most sidewalks are narrow and do not meet accessibility criteria, especially in metropolitan outskirts, with 14% of them being less than one meter wide, making it very difficult for vulnerable individuals to walk on them.

Benefits of Densifying Cities

A third finding from the new study relates to the benefits of densifying cities, meaning getting more people to live close together and in taller buildings rather than the increasingly common trend of creating peripheries with scattered houses where the only efficient way to move is by private vehicle. How can this be achieved? “Mexico City or São Paulo facilitate dense construction by eliminating requirements for developers to build large parking lots. Other requirements cities can reform include reducing the distance between buildings and the street or increasing building height limits,” says the researcher.

Manuel Franco, a research professor at Ikerbasque in the Basque Centre for Climate Change (BC3)—who did not participate in the study—states via phone: “Denser cities help people move more on foot because it’s harder to navigate them by car, and there are more nearby locations to visit, which encourages walking.” In his opinion, “the article shows that all cities can be made more walkable and highlights that walking has a very powerful impact on health and the environment as it reduces greenhouse gas emissions. Urban planning should prioritize this because it affects all of us as citizens.”

The study also concludes that in countries like India and the United States, where pedestrian mortality rates are high and rising rapidly, “the reduction of traffic accident deaths may be the most significant benefit of cyclist and pedestrian infrastructure. Other benefits include reduced air pollution and psychophysiological stress.”