Note: This post was originally published by Luis Natera on his personal blog. It has been republished here as part of TYN Studio's content.
How do cities integrate multiple transportation modes? Together with Federico Battiston, Michael Szell, and Gerardo Iñiguez, I worked on research examining urban mobility infrastructure as interconnected transportation layers.
The Multiplex Urban Fingerprint
We developed an "overlap census" methodology to measure what we call the "multiplex urban fingerprint" of cities. This technique analyzes nodes active across different transportation layers—pedestrian paths, cycling infrastructure, streets, transit systems—to determine multimodal connectivity potential.
Instead of looking at each transportation mode in isolation, we examine how they overlap and connect. A truly multimodal city has many points where different transportation modes intersect, allowing seamless transitions between walking, cycling, transit, and driving.
Global City Analysis
Analysis of fifteen global cities revealed six distinct clusters. Cities like Amsterdam, Barcelona, and Portland prioritize non-automobile modes, with extensive networks for walking and cycling that integrate well with other transportation options.
In contrast, cities like Phoenix, Mexico City, and Beihai emphasize car-dependent infrastructure, with limited integration between different transportation modes. The fingerprint of these cities shows heavy concentration in the automobile layer with minimal overlap with walking and cycling infrastructure.
Practical Application: Bicycle Network Planning
The research isn't just theoretical—we created algorithms identifying optimal locations for new bicycle infrastructure connections. The key question was: where should cities add new bike lanes to maximize the impact on overall network connectivity?
Testing in Budapest demonstrated that "with a small, focalized investment it is possible to have a great impact" on bikeable kilometers and network connectivity. Rather than randomly adding bike lanes, our analysis identifies strategic locations where new infrastructure would:
- Connect existing disconnected bicycle network components
- Maximize the increase in accessible destinations
- Integrate with existing transit and pedestrian infrastructure
From Analysis to Action
This type of analysis helps cities make data-driven decisions about infrastructure investment. Instead of relying on intuition or political pressure, planners can identify exactly where new bicycle infrastructure would provide the most benefit to the most people.
The multiplex network approach recognizes that transportation doesn't happen in isolation—people combine different modes in their daily trips. A bicycle lane that connects to a transit station and passes through walkable neighborhoods is far more valuable than one in isolation.
This research was published in Royal Society Open Science