Where the (Concrete) Sidewalk Ends

From bricks to cobblestones to recycled rubber, there are plenty of material options for sidewalks. But concrete is likely the cheapest.

"For most American cities, concrete is the go-to choice for building sidewalks. It's relatively cheap to install - only about $12 per square foot - and it's very solid. Its pale color reflects light, reducing nighttime illumination costs for cities compared to darker-hued alternatives. Plus, if adequately maintained, concrete can last up to eighty years.

Yet concrete also has its downsides: Manufacturing it has a high carbon footprint, since its fabrication requires the energy-intensive heating of limestone; it has a tendency to crack when tree routes grow underneath it; and it has no porosity, depriving the ground under it of essential ground water and increasing runoff problems."