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Sneckdown on a T-intersection in Sofia

A sneckdown[1] or snowy neckdown[2] is effectively a curb extension caused by snowfall. A natural form of traffic calming, sneckdowns show where a street can potentially be narrowed to slow motor vehicle speeds and shorten pedestrian crossing distances. Coined by Streetsblog founder Aaron Naparstek,[3] popularized by Streetfilms director Clarence Eckerson, Jr. and spread widely via social media,[4] the term first appeared on Twitter on January 2, 2014 at 11:19pm EST.[5] Other Twitter hashtags that have been used to describe snow-based traffic-calming measures include #plowza, #slushdown, #snovered and #snowspace.


Sneckdown on a corner in Allston, MA
  • Shortens pedestrian crossing time
  • Highlights unused road space
  • Calms vehicle traffic
  • Allows planners and road engineers to clearly see possible modifications to road structures
  • Encourages slower vehicle speeds, increasing safety for all road users, including pedestrians
  • Reduce asphalt surfaces, increase plant surfaces, improve the absorption of rainwater by the soil, reduce runoff and floods


  • Narrowing road also reduces time for driver to react when pedestrian steps on the road
  • Large vehicles are wider than their tracks on snow, so pedestrian can be hit by vehicle mirrors, corners or outstanding parts of the vehicle body/trailer
  • In case of a traffic collision narrow road is blocked
  • On narrow road there is no way to yield to emergency vehicles as required by traffic laws


Philadelphia, Pennsylvania – Baltimore and 48th Street: A sneckdown inspired permanent upgrades to the pedestrian environment at this intersection in 2011.[6]

In the 1980s, some planners in Australia distributed cake flour in intersections to observe patterns of vehicle movement hours later.[7]


  1. ^ "Streetfilms - Street Lessons from a Blizzard (with sneckdown!)".
  2. ^ "Streetfilms - Snowy Neckdowns Redux: Winter Traffic Calming (Now: #sneckdown)".
  3. ^ "Natural traffic control". The Economist. 13 February 2014.
  4. ^ "Streetfilms - The Complete Origin of the #Sneckdown".
  5. ^ "Aaron Naparstek". Twitter.
  6. ^ "Can Snow Inspire Better Streets? It Already Has". Streetsblog USA.
  7. ^ "Facebook".

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