I'm grey, you walk on me regularly, and you probably don't think about me too often unless you trip on a tree root or a crack in my side. Who am I? Why, your friendly neighborhood sidewalk, of course.
Most people don't give a second thought to the concrete they walk on every day, but some of us are starting to seriously examine the material beneath our feet. What if sidewalks didn't have to be so grey, boring, and - well - concrete?
A burgeoning industry in alternative sidewalk materials has paved its way into several experimental cities. Concrete - a mix of cement and aggregate - has always been the norm, because it's strong and cheap. But with winter's freeze-thaw cycles, crater-sized potholes and trees uprooting paths, concrete sidewalks are in constant need of repair and the costs are steep. Besides, grey concrete slabs are a bit of an eyesore.
The most popular new sidewalk technology so far is the flexible rubberized sidewalk, best known for being tree-root-friendly. The idea first came in the form of a dream to Richard Vareriano, founder of Rubbersidewalks Inc. For two decades, he worked as a street inspector in Santa Monica, searching for sidewalks broken up by tree roots. At first he and his chuckled at the idea of rubber sidewalks, but years later the idea arose again as an actual alternative to cutting down trees whose roots were tearing up sidewalks in Los Angeles. The rubber tiles, fabricated from old tires and recycled plastics, are now being tested in 60 cities across the U.S. It seems to be a win for all -- trees, citizens, and mountains of lonely old car tires.
Now folks are thinking beyond rubber and concrete, where the possibilities are endless.
Snowy cities like New York and Minneapolis are experimenting with heated sidewalks that melt surface snow and ice. Traditional concrete sidewalks are embedded with pipes of heated water, which greatly reduces need for shoveling as well as slipping hazards. As East Coasters all know, there is nothing worse than wiping out on the ice right outside your doorstep as you're running late for work or school. However, these fancy sidewalks do carry a hefty price tag of $100,000 for just under a block.
Instead of using up heat, other sidewalks produce energy. Pavegen, a company in the UK, saw power in people's feet - to generate capture kinetic electricity. These recycled rubber paving tiles capture the pressure of pedestrian footsteps to power nearby street lamps. Several cities across the UK and France are giving this a go in train stations, playgrounds, and offices.
Sidewalks can also produce energy passively, without the help of pedestrians. Why not bring solar to the ground? That's what George Washington University's Virginia Science and Technology Campus did with its "Solar Walk", a 100-square foot section of walkable solar panels. The small solar installation generates enough energy to power 450 LED lights in the pathway.
An even more hands-free (or foot-free) energy idea comes from Pro-Teq Surfacing, who built "Starpath", the world's first UV-powered pathway in Cambridge, UK. They created a spray-on substance that absorbs UV light during the day and releases a blueish glow at night.
Are these new materials worth the investment? So far, results have been mixed. In Santa Monica, gnarly tree roots have turned the flexible ground into a wavy funhouse terrain. Others say the rubberized panels only last two years versus their 7-10 year estimated lifespan.
We most likely won't find a concrete solution anytime soon. But as long as cities are willing to experiment, good alternatives will be found for people- and tree-friendly sidewalks, even if it means ditching the concrete.