Think of this Streetfacts chapter as a PSA about how, in just a few generations, we have tightly restricted American kids’ freedom to roam, play, and become self-sufficient.

The percentage of children walking and bicycling to school has plummeted from almost 50 percent in 1969 to about 13 percent today. Although distance from school is often cited as the main barrier to walking and bicycling, many families still drive when schools are close to home. According to the Safe Routes to School National Partnership, driving accounts for about half of school trips between 1/4- and 1/2-mile long — which in most cases shouldn’t take kids much more than 10 minutes to walk.

There are plenty of factors at work here: Lack of sidewalks and safe walking and biking routes. The fallacy of "stranger danger." School districts banning walking and biking outright. But all of these problems lead back to the original and biggest blunder: We continue to design our cities and towns for cars instead of for children, families, and human beings.