Interesting, thanks. I must admit I briefly misread the plot, and was confused why numbers were so low for those under 18, but I got it mixed up with the heart disease line... Oops.

But then I don't really see the puzzle for kids aged 5-14 at all. Half the group is too young to play near traffic, and instead stays home or in playgrounds. They don't have a driver's license and they largely sit in the back seat. And they are less likely to be out and about in the evening and nighttime when the drunk drivers get out on the roads. And they very rarely drive motorcycles, and I suspect folks with kids in the car are less likely to drive drunk or speed.