Tuesday, May 6, 2014

Imagining desire lines

You've seen them: lines where the grass is worn down, the evidence that enough people have walked a particular route as to kill the grass. They are called "desire lines" by landscape architects, and they are used to decide where to put new concrete or gravel paths.

The key point is that these bottom-up paths represent the desires of the people - the users of the space - in contrast with the top-down concrete paths that represent the desires of the planners and architects. The use of desire lines is an acknowledgment that sometimes the “wisdom of the crowds” – the aggregate of thousands of decisions made by hundreds of people, or more – can produce better outcomes than a handful of principled decisions made by educated professionals who may never actually use the space.

What are these better outcomes? Why do we care if people are walking on the concrete or the grass? Well, concrete is expensive and takes up space that could otherwise be planted with grass, so it pays to pour the concrete where it will be used. Dirt paths can be less comfortable, and some people don’t like the way they look. In general it’s more efficient for people to go where the infrastructure is, and for infrastructure to go where the people are.

It’s important to note that desire lines don’t tell you the whole story, because the decisions that create them operate within constraints imposed by others. For example, people may leave an asphalt path and cross a quadrangle diagonally to get to a door, because the asphalt path does not lead to a convenient door. Once they get through the door, they may travel down a corridor to a point just on the other side of a wall from the asphalt path. The best solution may not be to pave the diagonal path, but to open a new door in the wall.

Last week, Michael Kimmelman invoked the idea of desire lines to support his proposal for a streetcar running near the East River waterfront in Brooklyn and Queens. I read his post looking forward to hearing about how people are already trying to get from one part of the waterfront to another. Then I read it again, and again, but found no actual desire lines.

Kimmelman writes, "Cities also have desire lines, marked by economic development and evolving patterns of travel." Evolving patterns of travel, sure, but the only evidence he gives of these patterns is the Kent Avenue bikeway. Now I love the Kent Avenue bikeway, but it is no desire line. It’s a top-down effort, the result of years of collaboration between bike activists and city planners. Its popularity is largely due to the scarcity of safe alternatives.

I took Kent Avenue to work for a while when I worked downtown, but it was a significant detour for me. The quickest way for me to get downtown is the route of the Brooklyn-Queens Expressway, but I can’t ride my bike on it, there is no bike access on the Kosciuszko Bridge, and the parallel streets are hostile to cyclists. It is the planned concrete path. My desire line is the one traced by the young, tough, fast cyclists commuting down Metropolitan Avenue.

Similarly, the economic development invoked by Kimmelman represents not the desires of the residents, workers or shoppers, but the desires of developers and city planners, and the hate – the opposite of desire - of NIMBYs. The process of planning and zoning in this city favors people who have a lot of money, people who have fancy degrees, and people who have the time and energy to sit through community board meetings and the connections to get appointed to the community boards. That is why those buildings are rising along the waterfront.

Stephen Smith pointed out that Kimmelman is ignoring true desire lines, notably the ridership of existing bus lines. "What is the logic in investing a billion or more in upgrading a moderately-trafficked bus route in Astoria before far more heavily-traveled routes in neighborhoods like Flushing and Elmhurst?" he writes. "It’s hard to discern any motivation beyond the fact that existing high-ridership routes like the Q44 or Q58 simply don’t pass through gentrifying areas."

Other desire lines include the presence of non-government-sanctioned transit lines, like the Jamaican and Haitian dollar vans on Flatbush Avenue, or the Chinatown vans to Flushing and Sunset Park. Patterns of travel in taxis and private cars (or even bicycles, but with care) are other possible indicators. The replacement of any one of these by a faster, more efficient, less crowded train would be an improvement comparable to the replacement of a dirt path with a concrete walkway.

But the existence of housing developments and a bike path do not constitute desire lines, even if they are popular. Using these signs of the will of developers and planners to plan a train line is not like the bottom-up process of using the tracks of multiple individuals to plan concrete paths.

I'm honestly puzzled as to why Kimmelman misused the term "desire lines" in such a conspicuous way. I don't think he's deliberately being misleading, but I really expected him to know better. My most charitable explanation is that he was so excited at this idea (which he got from Alex Garvin) that he didn't really think through the idea of "desire lines" before hitting "send."

At least he's smart enough to avoid calling it "a desire named streetcar."


Elliot Schwartz said...

"more efficient to put people..."?

Capn Transit said...

Thanks for catching that, Elliot!

George K said...

It reminds me of a (small) example of a desire line in my neighborhood: goo.gl/maps/93yGR

However, instead of paving it, they put up a fence and blocked it off, as part of that whole "Adopt a Highway" stuff (and it wasn't like people were littering or loitering there or anything like that). Not that it's the end of the world to walk an extra 50 feet around it, except for the fact that the MTA also moved the S46 stop across the street, making it even harder to access (keeping in mind that the stop can be over a half mile away for many residents). Shows you how much of an afterthought pedestrians are in my neighborhood. SMH.