Opposite to what they are in the USA, they are the place where mass building has occurred, for or by the low income families. Generally, a house downtown is worth more than the same house on the edge. Even with 40 years of history of traffic congestions, it's still not bad for a location to have high traffic; actually, living in a dead end will lower the value.
The suburbs consist mostly of smaller houses, up to 100m2, with a bit of a yard in the front - usually not deeper than a few meters, with flowerbeds, often roses. Equally frequent is a pile of bricks, gravel or other material, as the people are building them on their own dime and move in before the house is complete, and then do the rest when (and if) time and money permit. Back yard may be the old peasant style, divided into the front part, where the kids play, car is fixed, chairs or a bench are under the tree (to sit on when weather permits). Behind that there may be an area fenced with chicken wire, with various poultry, most frequent being chicken, geese and turkeys. May also include a pig pen behind the house. Yet behind that there may be a vegetable garden and orchard, if space permits.
In the general case, there would be any combination of the above, with most or all of the agricultural parts missing, except the fruit trees, which are almost everywhere.
The streets are not much narrower than downtown, but the pavement is. The children are running around, with nobody watching them. Few stray dogs may pass, staying away from the people. It's generally silent, with occasional noise from a grinder, or some agricultural appliance, or someone's turbo folk music.