Houston Strategies

An innovation tailor-made for Houston: flexible sidewalks

A recent issue of Governing magazine has an article on the rise of flexible sidewalks made out of recycled tires. Since just about every sidewalk I've seen in Houston is busted up by the roots of our many wonderful trees, this seems to be a perfect product for our city. And it's a double-win: tires get recycled, and we get better and more durable sidewalks. Unfortunately, they cost more in the short-term, but the long-term savings are impressive. If any of you out there know people at the city's public works department, please forward this over to them.

Excerpts:

About 50 years ago, arborists in Santa Monica, California, chose ficus trees for the urban landscape. The trees have large canopies that provide shade and oxygen, beautify the city and increase property values. The problem is that little ficus trees grow up to be big ficus trees--with roots that can break up sidewalks and leave the city vulnerable to pedestrian trip-and-fall litigation.

Municipalities around the country have faced this problem since they began pouring concrete sidewalks 125 years ago. Indeed, concrete slabstend to suffocate tree roots, which then start to grow aggressively toward the surface. In the past, the remedy always has been to jackhammer the cracked sidewalk and pour new concrete. ...

Six years ago, Santa Monica installed the first rubberized sidewalk panels and it is still testing their merits. The trees clearly are faring better. Arborists speculate more water makes its way through the seams and some roots grow down, chasing the water. In addition, public works employees are able to lift the 2 x 2 1/2 foot "slabs" with hand tools and peek underneath to see how the roots are growing. When they picked up the rubber after six years, they found roots that were a lot smaller than the ones under concrete. ...

Altogether about 60 U.S. municipalities have installed stretches of sidewalk that are flexible and have some spring to them, similar to a rubberized running track. Rubbersidewalks Inc., a California-based manufacturer, has put its product through a battery of tests. They've been shoveled, sanded and salted, and subjected to high heels, oil, acid, coffee, bicyclists, children, chalk and paint. The company has safety-tested them for people on skates, in wagons, with walkers, on crutches and on bikes. Gum, tree sap, berries and pollen can be hosed off or steam cleaned.

On the environmental front, rubber sidewalks not only are kinder to trees but are manufactured from recycled tires. ...

Perhaps the biggest fans of the material are municipal risk managers and lawyers. In New Rochelle, where the sidewalks have been in place for two years, the tripping hazard around three trees has been greatly reduced. "The roots uplift the rubber sidewalks in a way that's still passable," says Jeff Coleman, commissioner of public works. "There's a nice gentle rise to them." ...

Initially, the cost for rubberized sidewalks is much higher than concrete. The 100-foot stretch in New Rochelle cost $8,000. Concrete would have cost $3,000. A lot of that has to do with the expense ofshipping the heavy material from the factory in California, and cities buying just a few pieces, rather than in volume. The company is planning a second factory for New York State and thinks that if the sidewalks take off, the prices will come down. But even at the higher initial prices, the equation changes in a few years when compared with the cost of having to remove and re-pour concrete. "After three years," Valeriano says, "we're not just breaking even, we're ahead of the game."

Update: Metro and Houston Parks and Recreation get onboard. Not sure if this is related to my request for forwarding, but if so, thanks!

posted by Tory Gattis @ 7:55 PM