Excellent thread. I grew up in a "close in" suburb of Boston. I spent all of my time playing in the woods or just "out in the street." I remember gangs of kids on their bikes, out until it was dark. I was going into Boston on the trolley, alone or with friends when i was 12.
That said, I noticed a distinct difference when I moved to sunbelt states at 16 and 21 (Florida and AZ). No kids out on the street. No teens riding bikes. No public transportation.... This was one of the reasons we left AZ. The saddest day was when my then 3 year old went into the shrub bed in front of our house in Tempe and said, "Look Mom, I'm in the woods!" Anyway, to make a long story short, my kids, now 21 and 23 played out in the woods. They made forts. They jumped off the deck into the snow and all kinds of sort of dangerous things. When they were young we lived almost 10 miles from their school, but when we moved my youngest rode his bike to school in middle school. He saved for a mountain bike and that very act change our whole family! He started riding, got a road bike, started racing, my husband started riding, then I did. If I hadn't let him ride to school, we wouldn't be riding now. They also did electronic things, especially computer games, but we limited it. By the way, I always worked, they were in daycare, we had a nanny, etc. and I didn't breast feed. I see many of the same comments from my students, Veronica. We went on a short hike on a trail for a science lesson andout of the 75 kids on my team, I'd say about 12 knew how to act in the woods, without complaining. They are not allowed to play outside, unless it's a structured activity. My kids spent many mornings laughing at the other moms and dads on our cul de sac who drove their kids to the bus stop... when our kids were standing out in the rain or snow....