Cities grow incrementally. A park bench here, a particular streetscape there, a zoning change, a new apartment or subdivision, a road widened, a transit line created.
Cities are organic. They change slowly. There are moments, however, when key projects - an expressway, a massive housing development, a huge investment in public transit - can bring dramatic change, for better and worse.
Toronto, for example, will never recover from the Gardiner Expressway, or from its unco-ordinated mishmash of waterfront developments.
Vancouver, by contrast, will benefit for generations from the intelligence of its waterside developments at Coal Harbour and Yaletown.
The essence of Canadian (and North American) cities since the Second World War has grown from the desire for single-family homes in suburbia and the consequent needs of the car, the preferred means of personal transportation.
The shape of every Canadian city reflects these choices that seemed, for so long, cost-free. Recently, however, a few cities have been rethinking sprawl, especially the costs it dumps on municipal governments to service far-flung areas and the environmental costs of all that car travel. Slowly, cities are beginning to wonder about sprawl and, in a few instances, trying to do something about it, however tentatively.
Ottawa City Council, for example, recently rejected its own planning staff's suggestion to add about 800 hectares to the urban area, some of which would be used for more single-family dwellings, despite the council's expressed wish for more intensification. The council did allow about 200 additional hectares by a one-vote margin, a display of how the forces of more sprawl, backed by the development lobby, remain powerful.
In Calgary on Tuesday, the council faces an even more consequential decision, whether to endorse the massive Plan It Calgary proposal that would set a framework for the city's growth for the next 60 years.
As in Ottawa, there are important elements on Calgary Council who believe the market should always prevail. People should choose how they want to live, runs the argument, and the job of the city is to allow those choices to be made. If the people want sprawl - single-family homes, large lots, personal automobile use to and from the from the centre - then so be it.
Plan It Calgary must be adopted at "third reading," as it's called. Two weeks ago, the plan's proponents figured they had only a one-vote margin.
Calgary's municipal scene shows much more diversity than its federal and provincial politics. There's more intelligent urban thinking than in many Canadian cities.
The in-fill development and intensification around the central core are excellent. So was the development of Chinatown. Three light rapid-transit lines operate, and a fourth is under construction. Compare that to Toronto.
All of Calgary's lines run above ground, unlike the silly Ottawa plan to drill a hugely expensive and unnecessary tunnel under the centre of the city for its first serious light rapid-transit line. Some of Calgary's newer suburbs have an unusually high level of density.
Plan It Calgary tries to outline how Calgary must incrementally change to accommodate 1.3 million more people in the next 60 years.
The emphasis is very much on rapid-transit expansion, density hikes around the LRT stations, much better street design, some new single-family subdivisions to be sure, but generally more intensive development.
For a city where the oil industry did everything possible for years to debunk global warming (an attitude now changed, at least publicly), planners talk on almost every page of Plan It Calgary about making the city "greener" and more energy-sustainable. Says the document: "The impact of fossil fuel use on the environment is well-documented."
Despite Plan It Calgary's excellent intentions, even if everything went according to its vision - including a population density of 27 people per hectare instead of 20 today - perhaps 60 per cent of trips by Calgarians in 2070 would still be made by car, compared to 77 per cent today.
Public transit is great, and more of it is needed. But changing the kind of cars people drive, and what fuels them, is even more important in reducing emissions.
Plan It Calgary's vision for tomorrow's city is on the right side of the future. Let's hope its proponents prevail today.