In New York City, the difference between a painted stripe and a physical barrier is not just aesthetic—it's a matter of 379 additional bike trips per station every month. Researchers at NYU's Tandon School of Engineering have delivered a definitive answer to a question that has long divided city planners: which type of bicycle infrastructure actually gets people to ride? And the verdict is clear: protected bike lanes work, while painted lines largely do not.
The study, published this week in npj Sustainable Mobility and Transport, analyzed approximately 72 million Citi Bike trips recorded between 2013 and 2024—a dataset so vast it provides a rare window into how infrastructure shapes real behavior at scale. Using rigorous statistical methods to isolate causation from correlation, the researchers discovered that protected bike lanes, which use physical barriers like curbs or flexible posts to separate cyclists from vehicle traffic, produce a measurable surge in ridership. Painted bike lanes and sharrows, by contrast, showed no statistically significant effect once researchers accounted for the fact that infrastructure is often installed in neighborhoods where cycling is already gaining momentum.
What makes this finding particularly powerful is how it cuts through the noise of preliminary data. Initial before-and-after comparisons seemed to show promise for all types of bike infrastructure—protected lanes showed an 18% increase in trips, while painted lanes showed 14%. But those numbers masked a crucial problem: cities tend to install bike lanes where cycling is already taking off, not in places where it needs a boost. By using propensity score matching and difference-in-differences analysis—statistical tools designed to compare truly similar neighborhoods while controlling for pre-existing trends—the researchers revealed the real story.
"When cities invest in cycling infrastructure, the design details can determine whether a lane simply exists on a map or actually changes how people travel," said Takahiro Yabe, assistant professor in the Department of Technology Management and Innovation at NYU Tandon. His colleague Marcel Moran, the paper's lead author now at San José State University, was equally blunt about the implications: "Painted bike lanes and sharrows may cost less and face less political pushback, but we now have evidence at a massive scale that protected bike lanes are really what can move the needle on ridership."
The research also uncovered a sobering reality: the benefits of protected bike lanes are not equally distributed across all communities. The positive ridership effect was statistically significant only in Census block groups with the lowest share of Black residents. In neighborhoods with higher shares of Black residents, protected bike lanes did not produce measurable increases in ridership. The researchers suggest that infrastructure alone cannot overcome deeper barriers—cost, discriminatory policing, and a history of exclusion from planning processes.
There was one bright spot in the equity picture. Older adults responded strongly to protected bike lanes, with particularly large ridership gains in Census block groups with the highest share of residents aged 60 to 79. The finding aligns with evidence from Copenhagen, a city renowned for its cycling culture and robust network of protected lanes, where older residents ride at high rates. The implication is clear: when we remove the fear of traffic, we unlock mobility for people at every stage of life.
As New York City continues to expand its cycling network, the research offers a roadmap. Build protected lanes if you want ridership to rise. But pair them with efforts to ensure that everyone, regardless of neighborhood or background, can actually benefit from them.