• Trey Hahn

Experimentation and iteration

Experimentation and iteration in urban planning- we've seen them with tactical urbanism. We've also seen them in the Alexanderplein project in Amsterdam, which I have written about before a few times. In this post I will argue why they are important for practitioners.


Iteration at the Alexanderplein intersection in Amsterdam:

photos before, during and after removal of traffic lights (Image credit from top to bottom: mattresses_of_amsterdam, siebeswartemmapeijnenburg)


1. Maneuver stakeholders and organizations

Baby steps are easier to take than big leaps, and a pilot can always be reversed. For uncertain stakeholders, having an experiment is lower-risk than immediate sweeping change. An iterative strategy can thus help you maneuver stakeholders and bureaucratic processes. It also enables you to gather data and conduct analysis, which helps with legitimization (as visible in the Alexanderplein project, see figure below). This connects well to the next point...


Alexanderplein project interview themes- adapted from Hahn & te Brömmelstroet (2020, p. 15)


2. Enable learning

An iterative project strategy and analysis work with and enable each other. And they are closely connected with learning:

Learning cycle for continuous improvement in public planning organizations (Hahn & te Brömmelstroet, 2020, p. 19)


Learning has the potential to happen on multiple levels. Using the Alexanderplein example: city staff learned a new tool for their street design toolbox, higher level decision-makers learned to conceptualize people interacting at an intersection in a new way, and Amsterdammers learned how to navigate a new design.


3. Take action

The Tactical Urbanist's Guide states it "is all about action". This is also key for experimentation and iteration. They help you put something out there and start a discussion, rather than being stuck. The immediate and low-cost infrastructural improvements may be the selling point, but you are also expanding capacity for the long-term. And who knows... an experiment may end up as something more!


"In the case of the Alexanderplein project, what was intended to be an experiment ended up becoming much more."

Hahn & te Brömmelstroet (2020, p. 19)

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