hes got a point though - why is 20 safe and 21 or 25 or 32 not?
A 100 yr old doing 15 mph is just as dangerous as a pregnant lady doing 32
Because he's talking apples and oranges. Dead is dead. It's faster to stop a car traveling at 15 mph than at 32 mph, if a child walks in front of a speeding car.
I just started reading this thread and this may have already been answered but one of the reasons for the lower speed limit in school zones is that if a child runs out in front of you, you are more likely to get stopped at a rate of 20 mph than 30 mph.