I live on a narrow street, with lots of trees, and lots of street parking, which makes it one lane in many parts. And Speed humps. It seems to make the cautious drive slower, but the speeders don't seem to be affected that much.
A valid point, but since it is a through street there are more speeders due to the higher total of cars on the road in general - It does not take that speeding cars to elicit fear. That was actually one of the first things I noticed after we brought the baby home - the speeding cars.