If a road needs to be less than 25MPH, it should be a dead end and not used as any sort of throughput, plain and simple. 20MPH in my car is about idling revs in 2nd, I really have no interest in running through town at 4000RPM in 1st.
And if your kids can't keep from running in front of cars, keep them in the back yard. If I'm driving like my kids live there, I am driving 30 anyhow.