Children? What does that have to do with anything? If you're letting children play in the street someone should contact social services because that is parental neglect. The street is a dangerous place and not made for children to play in.

If people are consistently speeding that means the speed limit is set too low. Statistical analysis along with several studies show that the speed limit should be at the 85th percentile to prevent accidents. My guess is they are not speeding at 40 mph but probably 30 to 35 mph and that is probably the more appropriate speed limit.