I grew up in a city of 2500 people, with vast distances. Of course people used cars for much, and no public transport. But the city centre was designed such that you parked your care one place, and then walked between all the stores. No having to drive through a big parking lot and crossing a street to get to the next store. I lived about 2km away from school, and biked, skied or walked every day, since it was designed a path for that. That path/road was completely separated from any roads cars would travel. So very safe. No one I know of got driven by cars to school.

Ironically, those making it unsafe for kids to walk to school, are parents driving their kids being short on time.

Point being, I have not only ever lived in dense urban environments. Secondly, that even those non-dense are perfectly viable to make safe for humans, and use less cars.