If you have sprawl-level densities around the HSR station, there is a sporting chance that someone will get pissed off that the existing residents are hogging all the valuable space right on top of the station with their low-density development.

- Jake

If you only spend 20 minutes of the rest of your life on economics, go spend them here.

... it is a system of direct, cross and hidden subsidies for sprawl development. You are concluding that the HSR will have sprawl impact by first assuming away the fact that spending on intercity road transport is one of those cross subsidies, and second assuming that the land use planning landscape under local control is a single, uniform mass with no local variation.

Spending on Express HSR intercity transport capacity instead of road intercity capacity is a dramatic change in the landscape. With the investment in roadworks, roads in the outer suburban area form dendritic networks draining toward the exit in the direction of the dominant commute. With investment in HSR, transport is focused on a single point with a 50km to 100km radius, and unlike land in sprawl suburbia, where land value is primarily created by zoning fiat, land value rises as you get closer to the station, on the natural square power relationship that there is only a quarter as much land that is half the distance to the station.

Now, you may believe that US local political systems are immune to the interests of property developers, but I do not. I believe that with a strong commercial interest by property developers in being permitted to exploit the value of proximity by being permitted to engage in mixed use and infill residential development, they will by hood or by crook get the station sited where they can get permission to engage in infill development.

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