They're called cars. Houses are packed tighter and there's more cars per household than when I was growing up (maybe due to everyone being double income now). Streets are also narrower and most have street parking, creating visibility issues. Go check out a development than went up 40-50 years ago compared to one that went up in the last 5 years. The difference is pretty stark and pretty hostile to kids running around doing kid stuff.
I don't think media's focus on bad guys has nearly the impact that the enormous increase in cars has had.