#SuperFlat: Smooth Sidewalks and Vulnerable Populations

For the first time in history, there are many people in the “oldest old” category, and this population continues to grow. These very old people can be considered the “new humans,” recent newcomers in the history of mankind.

-Sachiko Kamiyama, The Super Aged Society

A lot of factors go into creating a good pedestrian experience.  Many of them are visible and obvious: shade trees, wide sidewalks, narrow roads.  Smoothness of the pedestrian surface is not so visible or easily measured*, but it one of the most important factors.

First, let me introduce the shorthand “shuffler for a person at risk of tripping and falling during locomotion.  Shuffling is strongly associated with stroke and balance problems.  Shufflers frequently fail to achieve normal Minimum Toe Clearance while walking, and most shufflers are super-aged and/or suffer from osteoporosis.  They are individuals for whom tripping must be avoided at all costs.

Now we can analyse the hierarchy of smoothness:

  1. SuperFlat – smooth and flat enough for shufflers and wheelchairs.  Usage: indoor and covered walkways, sky-level walkways, maintained brick sidewalks, and unweathered roads.
  2. Flat – smooth enough for walkers and bikers.  Usage: older roads and concrete sidewalks.
  3. Rough – not smooth enough for safe use by walkers or bikers.  Usage: weathered roads and sidewalks affected by settlement, roots, or frost heave.

The distinction between Flat and SuperFlat may appear to be merely a matter of degree, but it is much sharper: a Flat path may be impassable for a wheelchair and dangerous for shufflers.

#SuperFlat sidewalks are critical for safe+healthy mobility/accessibility for the super-aged and other vulnerable populations.

The recent trend in Japan is to replace high traffic pedestrian pathways with SuperFlat brick.  This complements the longer term historical process of expanding the tunnel and sky-level pathways connected to rail stations.  Sky-level pathways are not affected by settlement or frost heave, and so maintain SuperFlat condition much better than surface sidewalks.


*I do have a heuristic for photos; if people are pulling wheeled luggage, the surface is probably SuperFlat.

Background Reading:

  • “falls injuries […] are the major precursor to death in the elderly “:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4021142/
  • “Only older adults reduced [Minimum Toe Clearance] due to fatigue”:  http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4253993/
  • “Osteoporosis was […] related to gait and balance deficits”:  http://www.ncbi.nlm.nih.gov/pubmed/19436938

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