A TND is sprawl. It’s enlightened sprawl, but it has the same unsustainable features. It’s not going to be persuasive enough to roll back planning to the past. The new science doesn’t roll back planning, it drives it forward. That’s why it will work.

Why shouldn’t authorities insist on predictability? That is what has been considered scientific for centuries. Predictability means progress. It certainly isn’t by creating failed TNDs that they will be convinced to give up on scientific methods. However if we can redefine what is scientific and show them another way to understand the processes of urban development, they may well be willing to switch to other processes in order to jump on board a whole new, forward-thinking scientific paradigm.

What we’ve found since modernist planning processes were widely adopted in the mid-20 century was that any space that somehow escaped the control of the authorities would become a spontaneous town, so there is nothing inevitable about sprawl. It is a choice by the authorities. It is a choice to give developers and property owners certain incentives. It is a choice whose consequences are not very well understood, and this is why this website exists, because it’s possible to make a different choice if we understand the consequences.

What’s not possible is to attempt to replicate spontaneous cities without changing any of the planning process. Cornell is only one failure amongst many others in that experiment.

In a traditional city there is no strict demarcation of “retail” and “non-retail” sectors. Commerce sets up where it makes the most sense for it to be. So a few very local services will build in between houses, while large shops will build along major integrator roads. There will be other uses randomly sandwiched between shops, with the frequency inversely proportional to propensity for commerce, and particular categories of commerce, of the space.

The mistake of the plan is defining a land use in the first place and building out the blocks too densely so that there remains no space to fill in late-stage additions to the neighborhood. Traditional cities don’t grow in solid blocks but in gradients of increasing density. That’s the source of their complexity.

Planning documents now reflect this, and support retail development on the distributor roads (which can be easily laid out in a new urbanist manner – nil street setbacks, on-street parking with rear service access, etc).

Distributor roads are also excellent and direct carriers of transit routes, and retail development provides a good buffer to residential uses behind, as well as significantly increasing opportunities for a permeable road layout. And it provides a fantastic treatment of what would otherwise be a traffic sewer, which is how Cornell’s perimeter roads are treated.

Can a plan ensure that businesses will set up shop there? Can it control economic forces that historically have taken decades to generate the current conditions?

New Urbanism is an intelligent design, creationist view of communities, that their genesis does not require evolution. In the same way, new urbanists come up with transects, which achieve through infallible directives what land economics would achieve in a much longer period, a density gradient from a designated centre outward. This is something that has always puzzled me. Why would you want to re-create in the lab the feature that is primarily responsible for sprawl, the density gradient from the centre to the expanding edge?

Rather than growing sprawl in the test tube using artificial land economics, why not grow medieval walled towns, using artificial brigands and wolves?