Density gets People Moving
I’m in Berlin this week, and I’ve been amazed how quiet it is. Unlike Paris or New York, where you’re always hearing trucks backing up, horns honking, and motorcycles zooming through, Berlin is stunning for its quiet.
Germans seem to put a premium on quiet. I remember a friend telling me that he’d gotten yelled at while living in Berlin for putting out his glass recycling after 10 pm. Apparently the glass makes too much noise when put in the bin, so please do that between the hours of 8 am and 10 pm only!
But here’s the thing. Berlin is a big city of 3 ½ million people—bigger than Paris, and soon to be the most populous city in Europe—when London leaves. It is also dense, with a population density of 3,750 people per square kilometer (9712 inhabitants per square mile). That’s among the densest in Europe and about 30% more densely populated than the densest US city (Los Angeles) and almost twice as dense as New York.
Even more so than in Paris, the density is achieved graciously. Residential neighborhoods cover most of the city, and include commercial and professional space on the ground floor. Offices and hotels are often intermixed in residential areas, and apart from a few industrial sites at the edge of the city and the governmental buildings downtown, there are virtually no areas without at least some expectation of residential units. Buildings in all of the close-in neighborhoods are 5- and 6-stories tall, and the streets are wide enough to accommodate broad sidewalks, street trees, and plenty of open air. Small and medium parks are everywhere.
So with all these relatively tall buildings and dense construction, how is it so quiet? A big part of the answer seems to be public transportation and bikes. The light-rail train network covers the city very well, and is sometimes at street level, sometimes below and sometimes above. By far it is the noisiest part of the traffic, but the noise is muted, isolated to those streets where it runs, and intermittent.
Because of its good public transit, Berlin has a high mode-share for public transit, with 30% of commuters traveling by bus or light rail. But where it really shines is in active transportation: 15% for biking and 29% for walking. These are among the highest rates in the world, exceeded only by Beijing and Shanghai. Dutch and Danish cities have much higher bike-shares, but correspondingly lower walking shares.
What’s striking from a public-health perspective is how density works to support active living. You don’t get to 29% of people walking to work unless there are a lot of people for whom work is only a mile or so away. And you don’t get to 15% biking unless a lot people work within 5 miles or so from home. And crucially, you can only get to those levels of proximity with a deliberate effort to promote and maintain density, as Berlin and other German cities have done.
Public transportation is not enough. Many American cities have good public transportation, and that helps with some level of active living. But the cities with the most active transportation mode shares—Portland, Seattle, San Francisco, DC, New York, Philadelphia—are in the 11-13% range for biking and walking combined, a far cry from the combined 30-45% achieved in many cities in Germany, the Netherlands, Denmark and Spain. Infrastructure is part of the reason for this difference. After all, Los Angeles is among the densest cities in the US, mostly flat and with fair weather, but has a combined bike and walking mode share of only 4% (albeit slowing growing). Clearly Los Angeles has both a major opportunity and significant work to do on its infrastructure. But for most cities, but density is surely another very important part. The protected bike paths in Berlin are wonderful and extensive, but people also quite happily bike in the narrow, unmarked margin of pavement between the tram tracks and the parked cars.
Density is a public health issue. It’s been clear for quite some time that the built environment is a crucial part of promoting active living. But until I spent a week in a city where active living is a part of everyday living, it wasn’t clear to me what it really looks like on the ground. Yes, bike paths, often separated, are a big part of it. Yes, parking is expensive. Yes, public transit works. But if we are serious about promoting active transportation, we’re going to have to sooner or later figure out how we can defend and promote density.