ETA relevant links: https://youtube.com/@NotJustBikes https://letgrow.org/
ETA again: I glibly mentioned "being killed by a driver" but of course navigating the typical US built environment if you're under 16 or otherwise unable to drive is a miserable experience in a number of ways even if you survive it. Highways make pedestrian paths unnecessarily roundabout. Parking lots make everything further from everything else. Crossing major roads requires getting drivers to notice and stop for you (harder when you're short!), or waiting through interminable signal cycles, etc.
It may depends on where in the US you're talking about, but in my area none of this is actually true. Although lots of people believe it is.
That's wonderful you live in place where children are can roam freely without being injured or killed by drivers. But this is a real threat in most of the US. Being killed in a motor vehicle crash is the second highest cause of death among children and adolescents. (It was the highest until 2020 when firearm-related injuries overtook them.[1])
For every 100,000 people the Netherlands has 3.8 annual traffic deaths, the US has 12.9, and Libera (the worst I could find[2]) has 35.9. That means when it comes to traffic deaths the US is 3.4x more deadly than the Netherlands and Liberia is 2.8x more deadly than the US.
I bike with my kids and let them walk to school and we talk about how to manage these risks. But being near roads in the US is less safe than most other developed countries by a statistically significant margin.
[1] https://www.nejm.org/doi/full/10.1056/NEJMc2201761
[2]https://en.wikipedia.org/wiki/List_of_countries_by_traffic-r...
The number of children who are killed by cars as pedestrians or bicyclists is much lower. In 2021 for example it was 176 pedestrian children and 38 bicyclist children [1].
[1] https://crashstats.nhtsa.dot.gov/Api/Public/ViewPublication/...