Pity the community with no sidewalks. It's a neighborhood in which no one goes anywhere except by car, and probably has little of interest within walking distance, anyway. A neighborhood where neighbors don't know each other.
I live in a neighborhood right on the main road. This is sometimes more curse than blessing. Traffic is fast-moving, and can be noisy. You take your life in your hands crossing the street. With the house set close to the road and our bedroom facing it, traffic noise comes right in the open windows of summer all night long. The sidewalk in front of the house is well-frequented, and some youth are thoughtlessly loud late at night. But I also have three supermarkets, two pharmacies, and several fast food outlets within less than a mile's walk. D.W. Field Park is just over half a mile away. If the traffic can be distracting on this side of our block, on the other side of it I heard birds singing only yesterday. Because we are on a designated school route, our sidewalks are plowed by cute little snowplows after every winter storm.
But even in my neighborhood, so well-suited for walking, many do not walk. Walking the dogs the other day I was struck by seeing lichens on the sidewalk. Lichens are delicate, slow-growing creatures. Yet here is a sidewalk only a few hundred feet from my door that is dotted with them. Surely they could not survive if that sidewalk got much use. I myself don't walk nearly as much as I should; it simply takes too long to get places. Or so I imagine. Whole weeks go by in which I go no farther on foot than is needed to walk the dogs.
The pale greenish spots are probably some species of Parmelia.
Regular foot traffic should have killed it.