How Urban Road Networks 'Evolve'

Think a city's road network is a result of rational planning? Well, think again. After analyzing over 300 cities -- both old and new -- scientists have discovered that cities tend to grow like organisms, and follow a similar mathematical pattern.

1 minute read

April 29, 2008, 10:00 AM PDT

By Christian Madera @http://www.twitter.com/cpmadera


"Next time you are lost in an unfamiliar city, console yourself with the knowledge that the layout of its roads are probably much the same as in any other.

French and US physicists have shown that the road networks in cities evolve driven by a simple universal mechanism despite significant cultural and historical differences. The resulting patterns are much like the veins of a leaf.

Marc Barthélemy of the French Atomic Energy Commission in Bruyères-le-Châtel and Alessandro Flammini of Indiana University, US, analysed street pattern data from roughly 300 cities, including Brasilia, Cairo, Los Angeles, London, New Delhi, and Venice.

They found that cities' road patterns have a lot in common mathematically, as well as looking similar to the eye."

Monday, April 28, 2008 in New Scientist

portrait of professional woman

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching. Mary G., Urban Planner

I love the variety of courses, many practical, and all richly illustrated. They have inspired many ideas that I've applied in practice, and in my own teaching.

Mary G., Urban Planner

Cover CM Credits, Earn Certificates, Push Your Career Forward

Logo for Planetizen Federal Action Tracker with black and white image of U.S. Capitol with water ripple overlay.

Planetizen Federal Action Tracker

A weekly monitor of how Trump’s orders and actions are impacting planners and planning in America.

June 18, 2025 - Diana Ionescu

Rendering of Shirley Chisholm Village four-story housing development with person biking in front.

San Francisco's School District Spent $105M To Build Affordable Housing for Teachers — And That's Just the Beginning

SFUSD joins a growing list of school districts using their land holdings to address housing affordability challenges faced by their own employees.

June 8, 2025 - Fast Company

Yellow single-seat Japanese electric vehicle drivign down road.

The Tiny, Adorable $7,000 Car Turning Japan Onto EVs

The single seat Mibot charges from a regular plug as quickly as an iPad, and is about half the price of an average EV.

June 6, 2025 - PC Magazine

SMall backyard cottage ADU in San Diego, California.

San Diego Votes to Rein in “Towering” ADUs

City council voted to limit the number of units in accessory buildings to six — after confronting backyard developments of up to 100 units behind a single family home.

June 18 - NBC San Diego

Large tower under construction with crane with American and Texas flags in downtown Austin, Texas against sunset sky.

Texas Legislature’s Surprising Pro-Housing Swing

Smaller homes on smaller lots, office to apartment conversions, and 40% less say for NIMBYs, vote state lawmakers.

June 18 - The Texas Tribune

Red brick five-story multifamily housing building in Edmonton, Alberta, Canada.

Even Edmonton Wants Single Staircase Buildings

Canada's second most affordable major city joins those angling to nix the requirement for two staircases in multi-family buildings.

June 18 - Canadian Broadcasting Corporation (CBC)