I think it's a bit different, too, when you are living in the country. On my dads street, all the dogs are allowed off leash and we know them all by name, and give them treats, they say their hellos and go back home - no main roads near, etc. It's just a different lifestyle. I don't totally agree w/ it, my dads house is the only house with a fenced in backyard that is actually utilized for our dogs, as ours aren't allowed free roam like that. But I could never imagine in a neighborhood the majority of ppl doing this, and how unsafe it would be.
For reference, here's my "backyard" at my moms house.
Not much for him to get into, but even so he'd NEVER be out without supervision and 90% of the time, he's on a long line.