According to New Urbanists Lucien Steil, Nikos A. Salingaros, and Michael W. Mehaffy, suburbs predate modern cities. That's a surprise for those of us who imagine suburbs to be a distinctly twentieth-century phenomenon.

Just because they've been around for a while though doesn't make today's suburbs an effective solution to the modern city. The authors point out that today's 'burbs are driven by a wayward dynamic code and that code resists change. In fact, the code becomes the tail that wags the dog - as our recent decision to run a subway to York University and beyond might illustrate.

The network, in turn, is determined by current social, political, and industrial practices in transportation and energy use and availability. Building a subway to connect low-density sprawl makes little economic sense if the transportation patterns generating sprawl remain in place; such a high-capacity heavy rail system should be reserved for a medium-to-high density city.

How do we make changes to the code? The authors call for an incremental strategy with five priorities:

PRIORITY ONE: Define new neighborhood structures of centers and boundaries.
PRIORITY TWO: Network the existing infrastructure.
PRIORITY THREE: Insert monumental connections, screens, and vistas.
PRIORITY FOUR: Divide oversized blocks into urban blocks (the scissors technique).
PRIORITY FIVE: Change the "operating system" of suburbia to facilitate further incremental reform.