A new study came out about kids and utilitarian exercise (exercise you get while running errands or commuting) and found that
about as many kids stay active by pedaling their bikes to a friend’s house or walking around a neighborhood as do others by participating in organized athletics.
Which is interesting since I never see kids in DC biking to school. I live near a school and never see bikes locked up there. Which is too bad because
About one in eight American children bike or walk to school as compared to one in two children 30 years ago. The percentage of children who are overweight has more than doubled in the same time frame.
Which does not mean there is a cause and effect, but common sense says they're linked. A more interesting realization was then when kids spent more time riding bikes recreationally, they used them less (though not much) to go to their friends and vice versa.
The civil engineers also estimated the impact of adding exercise-enticing features to a neighborhood, and found they provided modest benefits. The study showed that increasing the number of bike lanes by 25 percent might increase the time spent in recreational travel in a neighborhood by 15 percent. Concurrently, the time kids spent walking or biking around their neighborhood would then drop about 1 percent. As a result, their overall physical activity levels only increased about 2 percent.