Fourth Environment

Real Estate Development + Urban Design

The Adaptive Code

an idea under construction


The Adaptive Code is a concept for a new way of regulating real estate development in cities. The code is meant to be simple and minimalistic, while providing a framework for a city to thrive in all four environments.


We need a lightweight, straighforward, foolproof form-based code that can be understood and implemented by *anyone*. The code needs to make sense to people of all political leanings, and it needs to work for 100+ years without being recalibrated.

For a longer explanantion of why we should bother with an Adaptive Code, feel free to read our introductory paper, which explains the problems with the current system and more of the rationale behind the proposed code.

Download the Introduction [PDF 142kb]

Inspired by Nature

Cities are messy and chaotic, so how do we best manage them? If we look to nature for inspiration we can find many examples of city-like systems that function quite well.

Consider the termite mound. Individual termites have no intelligence, but by following a few simple behavioral rules they create incredibly efficient mounds. Termite mounds, anthills, and behives are all examples of natural phenomena called Complex Adaptive Systems.

Characteristics of a Complex Adaptive System

What does this teach us about cities?

If cities are complex adaptive systems, we need to change our regulatory philosophy.

We need to let go of top-down planning, and instead find the simple rules that allow self-organizing, bottom-up emergence.

The Adaptive Code is a schematic framework for such a system.

Principles of the Code

  1. Favor free-markets over management, bottom-up emergence over top-down administration.
  2. Only regulate what is essential to:
    1. Promote long-term stability and appreciation in property values.
    2. Eliminate externalities.
    3. Favor consumption-based fees over flat-rate services.

The Model

1. Start with a street pattern.


All development must extend this pattern outward or offer equivalent connectivity.

Allow half-streets and dead-ends to facilitate incremental extension of the urban fabric.

2. Establish a transect of complete street types.


All new streets must conform within acceptable limits to one of these types.

3. Map existing streets to the new types.

Any non-conforming streets must be reconfigured the next time they are rebuilt.

4. There may only be one street type per block segment.

Block segments run from intersection to intersection. Adjacent block segments may only change up or down by one level of intensity.

5. Define appropriate building scale and disposition requirements for each street type.

All future development must conform to the requirements associated with the type of street on which it is located.

6. Universal building requirements:

7. Greenfield developments may be built at any intensity

The developer must provide the appropriate street type for whatever intensity of development he wishes to construct. Connecting block segments on the edge of the site must be scaled within one intensity level of adjacent segments.

The City will not fund any portion of any cost associated with extending infrastructure to greenfields.

8. Option to scale-up by right:

If the city or a developer wishes to increase the allowable intensity of development on a block face they must first upgrade the infrastructure accordingly. A developer who pays the full cost of upgrading an entire block segment to the next level of intensity gains the right to build at a higher intensity level on that block segment.

9. No parking minimums or maximums.

The city will use congestion-pricing and parking meters to regulate the supply of on-street parking in such a way that there is always one space available on each block face.

10. No land-use zoning, but no externalities allowed.

Maximum noise and light levels specified for each street type by hour of day. Proximity limits for noxious uses allowed, e.g. adult-oriented businesses may be limited from building in proximity to schools.

11. Miscellaneous

No new construction in flood plains. No flat-rate solid waste collection, instead charge for solid waste by the pound.


Within this framework, individuals have maximum freedom to enjoy their property as they see fit, while eliminating the ability of development to fragment the urban fabric, and greatly reducing the ability to degrade the pedestrian realm. The human-scale city is able to emerge organically.

Thank you for considering this concept, I hope you find it interesting. If you have questions or comments:

If you like this idea and would like to hear from me occasionally about this and other projects I'm working on, please sign up for my email list. I'll send you updates a couple of times per year.