I think it's also a result of car ownership. It wasn't until the 1980s that multi-car households started being really ubiquitous. I imagine people slowly start

I think it's also a result of car ownership. It wasn't until the 1980s that multi-car households started being really ubiquitous. I imagine people slowly started driving their kids to school because they could, which led to other people driving their kids to school because walking/biking was unsafe due to all cars on the road. My childhood in the 90s kinda sucked by comparison because I was in small neighborhood with no kids my age locked in by a busy road that was too unsafe for me too cross on my own.