Was out in the suburbs of Copenhagen today for a bit, and they look, well, a lot like American suburbs except with smaller-than-average houses. But if you go visit an American suburb with smaller-than-average houses—usually an older one—then you’ll very much have the right idea. What was quite different, however, was the transportation from the suburbs into the central city. Copenhagen’s suburbs are organized around the “finger plan” illustrated in the map on the right. Each finger is, as you would do in the United States, built around an arterial road. But the roads have fewer lanes than an American arterial would have. But running alongside them (or at least running alongside the one our bus was driving on) are very nice, very wide bike paths. And roughly parallel to the roadways are the S-Tog commuter rail lines.
Consequently, there are fewer people driving on the road than you would have in the US and there are more people biking and taking the train.
It’s worth noting that this sort of thing leaves overall automobile congestion neither better nor worse than an alternative strategy of fewer options and wider roads would. Insofar as you build road capacity, drivers will fill that capacity up. You get a choice of what level of automobile traffic you want to see the congestion at. But if you actually want uncrowded rush hour roads then you have basically only two choices. One is that you can build “road to nowhere” type projects where the economic rationale for infrastructure development is so poor that people don’t really want to drive on your shiny new highway. The other is that you can do congestion-pricing. But absent congestion-pricing, even the really admirable provision of alternative modes has limited impact. When valuable goods are given away for free, you get shortages. Copenhagen is apparently considering following Stockholm and Oslo and implementing a congestion fee, but they haven’t done it yet.
Still the moral of the story is, I think, pretty clear. When you build infrastructure to facilitate commuting from suburbs to central cities, lots of people will avail themselves of the opportunity to move to the new suburbs. But how they actually get to the central city depends on what kind of infrastructure you build. If you build giant highways, they’ll drive. If you build smaller roads and also some trains, then some people will drive and some will take the train.
For the sake of comparison, note that Copenhagen is a pretty small city. There are 521,000 people in the city proper and 1.8 million in the metro area. That would make it the 30th largest metro area in the United States, slightly bigger than the Las Vegas MSA and slightly smaller than the Kansas City MSA. All told, about 129 million Americans live in metropolitan areas that are bigger than metro Copenhagen. About a third of Danish people live in Greater Copenhagen, whereas over 40 percent of Americans live in metro areas that are bigger than Greater Copenhagen.