For reasons of safety and ease of maintenance, Washington and dozens of other communities are installing rubber sidewalks made of ground-up tires.
The rubber squares are up to three times as expensive as concrete slabs but last longer because tree roots and freezing weather won't crack them. That, in turn, could reduce the number of slip-and-fall lawsuits filed because of uneven pavement.
The shock-absorbing surface also is easier on the joints of joggers and is more forgiving when someone takes a spill.
And the rubber sidewalks are considered more environmentally friendly: They offer a way to recycle some of the estimated 290 million tires thrown out each year in the U.S., and they do not constrict tree roots the way concrete slabs do.
"As our trees grow and mature, sometimes the root systems begin to pull up the sidewalks," said Michelle Pourciau, acting director of the D.C. Transportation Department. "This is compromise between having a beautiful and healthy tree and having a safe and passable sidewalk."
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