Sneckdowns: How snowstorms can teach us to build smarter roads

The powerful winter storm burying the Northeast in snow is making life miserable for commuters, postal carriers, and pretty much anyone who has to venture outside. But while all that snow is a hindrance to travel in the short term, it could play a role in making travel better, or at least safer, in the long term.

Meet the sneckdown, a public planning nerd's favorite winter weather tool. A combination of "snowy" and "neckdown" — a term for traffic-calming curb extensions installed at intersections to narrow streets, giving pedestrians a shorter distance to cross — sneckdown refers to the roadside swaths of snow and slush left untouched by tire tracks.

Some examples:

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You get the idea.

These unblemished patches of snow reveal where vehicles actually travel on roads; they're "nature's tracing paper," as Clarence Eckerson, Jr., says at Streetfilms. They also help us better understand how roads can be redesigned to reclaim paved space and be safer.

"The wider a street, the safer drivers feel exceeding the speed limit," according to Transportation Alternatives, a New York City advocacy group. "Where normally drivers are jockeying for position, snow banks on both sides of the street keep drivers in line and in their lane, demonstrating how narrow the street could be."

(Full disclosure: I am a card-carrying member of Transportation Alternatives, and an avid cyclist.)

Since at least the 1990s, urban planners have observed pedestrian and vehicle tracks in the snow to analyze our travel patterns. Eckerson shot two short films, in 2006 and 2011, documenting the phenomenon. Here's the more recent:

In 2011, Philadelphia actually used sneckdowns to redesign a major street corner. "For us it was just a really compelling way of showing there was way too much street and not nearly enough place for people," Prema Gupta, a city planner involved in the project, told Streetsblog. And in Raleigh, N.C., the Office of Transportation and Planning this week urged residents to share their photos of sneckdowns.

Back in the '80s, engineers in Australia dusted intersections with flour to achieve the same end. After waiting a few hours, they photographed the intersections from high up, revealing where and how roads could be tweaked.

And that's exactly why proponents say sneckdowns are so valuable. Plotting roads based on estimated traffic patterns is one thing; observing traffic patterns in real life — and learning from them — is another. Sneckdowns "let you watch real-time human behavior," Gary Toth, of New York's Project for Public Spaces, tells The Economist, "rather than using computer models to predict it — models that often get it wrong."

Now, snow isn't an infallible predictor of travel patterns. Like pedestrians plodding along in existing footprints, cars, too, often follow each others' tracks through snow to ensure better traction. And with curbs covered in a thick coat of powder, drivers are more liable to bunch in the center of roads to avoid inadvertently thumping a hidden protrusion.

Still, sneckdowns offer a handy — and free — guide to finding potentially wasted space on the roads.

"Certainly taking a photo of a sneckdown does not equate to an absolute mathematical seizure of asphalt to implement traffic calming," Eckerson says. "But it does show where there is a strong, inspiring possibility for change."