The American frontier economy was based on settlement in newly taken land, building up the economic value of the settlement by establishing a local export-based economy, and then the next generation moving on to the next zone of newly taken land.

After the frontier closed around 1900, America eventually settled on the highway system as a way to engineer new frontiers to engage in the same process.

Even as dimly as I see a European model, and as briefly as I sketch that above, it is easier to see how it becomes a sustainable steady state system by providing for a regular outmigration from the urban centre to the hinterland (which may be smaller centre in the hinterland).

Making a frontier expansion model sustainable is tougher, and I am sure some would argue it is impossible. My outer-suburban retrofit ideas diaried in the Daily Kos involves using an interegional public transport line as the infrastructure subsidy for a process of frontier settlement of low density outer suburbs with a network of higher density outer suburban villages.

However, on its own it is only a transitional system. The hope is that it is a transition in the direction of sustainability, rather than another transition trying to avoid sustainability.

{NB. I try to speak very carefully here of A pattern IN Europe as opposed to THE pattern OF Europe. "Singular and comprehensive" pattern is not assumed.}

I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.