During any of the several recent catastrophic blizzards that have draped the country with snow, you might have seen people tagging their photos #sneckdown. No, it's not a protective garment you wear to keep your neck snow-free (although that could also come in handy!). It's a word coined by transportation geeks.
"Neckdown" is a somewhat wonky term used by traffic engineers for the extended pedestrian areas you'll see at crosswalks, says Clarence Eckerson of Streetsfilm. "The more common term is curb extensions or bulb-outs," he tells Gizmodo. "These are a proven form of traffic calming that narrows the roadway so pedestrians have a shorter distance to cross at intersections. They also cause turning cars to slow down and be more careful making their turns."
When it snows (a lot), it essentially turns the entire city into a data-tracking system—which can record the way people move through it. Slowly, paths are carved through the snow by cars, plows and pedestrians, with the most heavily traveled paths eventually revealing the pavement below.
What you start to notice is that cars drive in a very narrow area compared to the width of the roadway, revealing untouched mounds of snow around the corners of the streets and intersections. The snow temporarily shows where neckdowns might be possible, by illustrating the space that's rarely used by cars.
How Snowstorms Reveal the Wasted Space on Our Roads