Children do play on city streets, however one of the big differences is sight lines. Suburban streets tend to be dangerous due to visibility issues and often lack well connected sidewalks etc.
A core reason for this is developers want to maximize the number of houses they can fit on a given plot of land which will often have odd shapes etc. So kids simply walking to a friends house are often in real danger.
A core reason for this is developers want to maximize the number of houses they can fit on a given plot of land which will often have odd shapes etc. So kids simply walking to a friends house are often in real danger.