Ildefons Cerdà, the Art and Science of City Design

The Founder of Modern Urbanism as a Source of Inspiration for a New Generation of City Designers

Ramon Gras (MDE '18)


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Last Wednesday, April 4th, 2018 the Harvard Graduate School of Design hosted the presentation of the very first translation into English of Ildefons Cerdà’s fundamental theoretical writing, his monumental General Theory of Urbanization. Originally published in 1867, and now edited by the Institut d’Arquitectura Avançada de Catalunya and ACTAR, Cerdà’s foundational book constituted the very first attempt to systematically define Urbanism as a new science and professional discipline. In this article, I would like to succinctly highlight three reasons why his legacy stands out as a seminal reference of the highest quality, as well as a source of inspiration for new generations of urban designers, eager to provide appropriate responses to the needs and pressing challenges our cities face today.

Design Thinking | Urban Design as a form of Art

Cerdà’s revolutionary vision led him to pursue highly idealistic goals by deploying extremely pragmatic and grounded design methodologies. His creative endeavor focused on responding to the urgent need, spurred by the emergence of the Industrial Revolution, for a systematic understanding of what modern cities were and could eventually become, by transforming a once unstructured and outdated set of minor disciplines into a cohesive, rigorous profession. He started by coining a set of concepts that would allow him to codify the fundamental elements and dynamic systems that constitute modern cities. Way before the words urbanism, Städtebau or City Planning started being used in city-related studies, he coined the word Urbanization (1). Cerdà was the very first City Designer to overcome the traditional planning routines inherited from pre-Industrial times, by proposing a set of rigorous methodologies to integrate all the techniques and design considerations that should be harmonized to successfully address the problems that modern cities necessarily face.

Systems Engineering | Urban Design as a Science

Cerdà understood that modern cities require the juxtaposition of complex systems to effectively deploy the multiple services enhanced by the technological advances of the Industrial Revolution. His innovative vision allowed him to systematically address qualitative challenges by developing quantitative models. His ultimate goals addressed considerations such as eradicating early child and mother mortality, increasing the standard of living of working class families, merging social classes within the same neighborhoods and buildings to reduce social stratification, drawing specific street patterns to induce egalitarian power relationships, balancing the human need for isolation and privacy with the ability for people to socialize, prioritizing pedestrian mobility and sociability over alternative means, or establishing efficient mobility and energy systems able to adapt to further foreseen technological changes. To address such challenges, he designed a series of probabilistic, non- deterministic heuristic models, based on extensive avant la lettre Big Data analysis. Cerdà iteratively refined and sophisticated such methods, allowing him to come up with ranges for optimal building height, footprint, and density; street and sidewalk width; integrating all urban services in the very same way we still do to this day. His envisioning of a grid system became a reference for all grid models that came after his Barcelona Expansion plan, including Manhattan in NYC.

Human-centered design | Urban Design as a Service

Ildefons Cerdà developed his main book whilst designing the Barcelona Expansion Plan, completed in 1859. Not only did his plan accomplish all the fundamental goals it pursued in a masterful way, but it also represented a benchmark for high quality urban design practice. Today we can empirically contrast not only the lasting achievements that his plan brought for the city of Barcelona, but also the benefits of well thought design methodologies. By way of example, recent studies comparing the cities of Atlanta and Barcelona (2) show how metropolitan areas with a comparable population can embody massive differences in terms of environmental footprint or transportation efficiency (3).

For all these reasons, Cerdà is a source of inspiration for new generations of city designers who want to contribute to the enormous technical and social challenges that the discipline of Urban Design needs to respond to in this age of rapid and often abrupt technological changes with a human-centered and rigorous approach.


  1. The Guardian. Barcelona's unloved planner invents science of 'urbanisation'.

  2. Alain Bertaud

  3. World Bank. Follow the moving carbon: A strategy to mitigate emissions from transport.