You know when you're driving east on Interstate 10, past downtown Los Angeles, and all you can see ahead of you is the jumbled horizon of rooftops, trees, and overpasses? That is, according to the latest Census figures, the true face of density. Don't let any skyscraper-dwelling, subway riding Chicagoan, New Yorker, or Philadelphian say anything different. 

Today the US Census released a slew of city-related data from the 2010 Census, and it includes some figures about California that will be startling to anyone who hasn't been paying attention for the past few decades. It reveals that, contrary to 20th century images of shuffling hoards that populate eastern cities, the West now has by far the most dense urban areas in the country. Nine of the top ten densest urban regions are in the west, and the top four are all in California: 

  • Los Angeles-Long Beach-Anaheim ("about 7,000" people per square mile).  
  • San Francisco-Oakland (6,266)
  • San Jose. (5,820) 
  • Delano, Calif. (5,483) 

New York-Newark comes in at is fifth, with 5,319 people per square mile. 

Setting aside Delano's unexpected star turn, none of this should come as a surprise to planners in California (which also happens to be the "most urban" state, with 95% urban residency). Density is what happens when you build freeways all over the place and everyone gets to live all over the place. For all the objective connotations of these figures, there's no doubt that there's plenty of room for interpretation, which can have deep implications for public policy.  

Measures of Density

Seven-thousand people per square mile. Does that mean that I'm sharing my particular square mile with 6,999 other people? Of course not. These Census numbers, like almost all statistics, are crude, insofar as they refer to entire urban areas. Moreover, measure of density depends on where demographers draw the line around the "urbanized area." For instance, Manhattan tops out at an astounding 560 residents per acre. San Francisco's central city comes in second place nationally, with 260 per acre. Los Angeles' center city density is 70 per acre. Meanwhile, though Chicago's residental densities are simliar to those of Los Angeles, its central city has 2,200 jobs per acre, compared to L.A.'s 1,200. The moral of the story: the Los Angeles region's density is high on average but evenly spread. New York, Chicago, and the Bay Area have much greater densities in their central places, but then they peter out into more bucolic places like New Canaan, Buffalo Grove, and San Rafael. 

Sprawl vs. Density

This is one of the bigger non-debates in urban planning. It was stoked a few years ago by Robert Brugmann in his book Sprawl: A Compact History. In short, he argued that the definition of sprawl--i.e. his definition of sprawl--precluded density. This definition implies that sprawl exists only where development has used greenfield land inefficiently, to create spread out houses on the urban fringe. But Brugmann was disingenuous. Density is a demographic measurement. Sprawl refers to the form of land use. That's why CP&DR publisher Bill Fulton has long referred to the Los Angeles area as "dense sprawl," because the built up area spreads out to the horizon despite the fact that it is dense. After Southern California's initial phases of leapfrog development, cities filled in the empty spaces, resulting in a density gradient that is remarkably uniform throughout the region. 

Interestingly, this pattern continues in the developing world. A recent study sponsored by the Lincoln Institute for Land Policy found that cities in Latin America are growing larger not by consuming more land on the urban fringes, but rather by filling in undeveloped patches. This pattern means that urban land cover is increasing at surprisingly high rates, because the consumption of infill land is, according to the authors, harder to perceive than is the consumption of urban land. In the Los Angeles area, "dense sprawl" means that residents are living at high densities and yet are spread over a wide geographic area and often in places that don't offer convenient local services. The result: traffic.  

Crowding vs. Density

In the popular imagination, I gather that there is little distinction between crowds and density. But the two could not be more different. Los Angeles seems like it's not dense because it has few crowds - no Times Square or Michigan Avenue (and no Union Square or Delores Park, for that matter). We rarely experience what P.J. O'Rourke refers to as the "jostle and squash" of urban life (he was talking about the grandstand at the Kentucky Derby, but same difference). So Los Angeles doesn't feel dense because it's not crowded. Until, that is, you enter the Santa Monica Freeway at 5pm. 

The Culture of Density

The more I visit other cities and the more we discuss the Red State/Blue State divide (which you can extrapolate to Red/Blue counties and even Red/Blue neighborhoods), the more I believe that urban life depends as much on attitude as on demographics or even urban form. Los Angeles has a long history of pretending not to be dense - because for a while, it wasn't. 

But even though apartments have replaced single-family homes and we've now hit 7,000 people per square mile, I've always felt a palpable longing among many L.A. residents for the old days of privacy and disconnection. You see it when homeowners protest against apartment developments and when they rail against anything that would bring more cars to a given neighborhood. L.A. does not have a tradition of strolling about or spending afternoons in the park. We look at fellow Angelenos with suspicion, as if each one of them is a competitor for the last open parking space on earth. By contrast, a city like Portland, Oregon, embraces walking, biking, and riding public transit even though the urban area is not nearly as large or dense as those in California. That's a cultural choice that Portlanders have made. Meanwhile, down south, the backyard, the fence, and the swimming pool dominate the city's mentality, no matter how many thousands of neighbors you have. 

Density and Urban Form

Generally, progressive planners and smart growth advocates seem to like density. In its crudest form, greater degrees of density probably can lead to more functional, pleasant cities. But it's not the numbers that matter. The L.A. area could have a density of 7,000, 14,000, or 1,000. As I told the L.A. Daily News' Dakota Smith for her article on this very subject, what matters is how a city carries its density. 

Some dense cities (NYC, San Francisco) have great transit and appealing streets. For instance, according to the University of California Transportation Center, the combined percentages of commuters who walk or use public transit in New York is 36%. In SF-Oakland, it's 20% and in Washington, DC, it's 18%. Los Angeles? 8%. Meanwhile, some sparsely settled cities (Salt Lake, Phoenix) have wide, fast boulevards that, if not pleasant, at least make them easy to get around. Then there's Los Angeles, which offers the worst of both worlds: it's too dense for traffic to flow, but not quite dense enough--and not designed well enough--to foster the street life that makes other big cities so wonderful. 

The Future of Density: Smart Growth & SB 375

The relatively uniform density that has arisen in Southern California, thus far, is largely the result of a relatively free market for development and the relative dominance of the automobile. In this land rush, quantity overwhelmed quality, and the result is the land use equivalent of a television tuned to static. It's busy, uniform, and incoherent. More entropic than organized. 

For about the past few years, however, planners in California have been trying to figure out what do with all this density now that we have it. The solution--or so some hope--is Senate Bill 375. While full implementation is still a long way off, the intent of SB 375 is to do exactly what California's major urban regions have not done in the past: it focuses density into places that can best accommodate it. Public transit offers the most obvious accommodations, and SB 375 encourages cities to nudge dense development towards light rail stops, major bus routes, and the like. It also promotes a better mix of residential and commercial, so that one day residents can walk around the corner for that quart of milk rather than drive to the Super Walmart. 

If cities implement the tenets of SB 375's Sustainable Communities Strategies--regional plans being drawn up by the metropolitan planning organizations of San Diego, Sacramento, the Bay Area, and Southern California (Los Angeles)--then density may no longer be hidden. It will be plain to see in the streetscapes. And if California residents can accept the fact that we are, indeed, an urban state, maybe, by the time we hit 8,000 per square mile, we'll look like one too.