Understanding American "safest vehicle on the road"

School bus -- Something I've never experienced as growing up in another country where I went to the elementary school on foot, went to junior high school by bicycle, then went to high school by a train (that passes in the middle of the school yard of the very school in the city of Utsunomiya). My story aside, boys are now going to the same school as a 2nd grader and a pre-K. In the beginning when the emotionally developing 4-yr boy started, there was some dramas, but 1 month passed he seems to thrive.

It leaves our neighbor hood punctually at 6:52am every weekday. While being freed from 2 of 3 kids that early everyday is a huge help despite early morning hassles of making lunchboxes, the most helpful aspect of it is its reliability. As NHTSA (National Highway Traffic Safety Administration) puts (nhtsa.gov), "school bus is the safest vehicle on the road".

While I've always assume so without really trying to understand what makes that propaganda true, a tragedy occurred earlier this month in Japan struck me... A 3-yr old remained in a school bus after the morning pickup and found dead (japantimes.co.jp) around lunch time, in a Summer heat. Along with the national sensation, American school bus system is highly accoladed. While I agree from my experience as a dad with less than 2 year of sending kids on school buses in the US system, I realized I have lots of things I don't know about school bus system. Following is some of my questions and the answers I figured out (i.e. Answers my own).

Q. Around what time regulation went into effect?
A. School Bus Wikipedia page (wikipedia.org) summarizes a historical development of the design and regulations. In 1939 (80+ years ago!!) there was already 44 safety standards agreed upon nationwide. 1973 (50 years ago!), the first federal regulation for the manufacturing school buses went into effect.

Q. What's the rationale for no seat belt?
A. Looks like multi-faceted but I see main two points. 1. (Structural) For a vehicle with certain weight, the impact of the crash distributes evenly. 2. (Counter measure: Passive restraints, compartmentalization) Study showed the most effective protection is the seats with certain material, the height and spacing from adjacent seats front and back of itself.

Q. What is the protocol and supporting system to make sure no child is left in the vehicle?
A. (This is what's triggering debate in Japan. Haven't looked into yet)

Q. What's the requirement, compensation of bus drivers?
A. They're hired part-time, dedicated (no teachers or any duties at school). fcboe.org, the county we're in, claims full-time equivalent exceptional benefits.

My self-education to be continued.

Picture from very 1st day HG started at a public school, came back home in 2021 (hence face mask)