@aisyna The laws vary by state.
Here is what the pros say about bus design and seat belt use:
“Information from all types of school bus collisions demonstrates that the current school bus design provides a high level of protection to occupants and that seat belts may actually adversely affect the safety of children on school buses.
Instead of requiring seat belts, school buses are designed and constructed differently from passenger cars. School buses protect passengers through “compartmentalization”, a design that includes:
* Seats with high backs;
* Seats filled with energy-absorbing material;
* Seats placed close together to form compartments;
* Strong seat anchorages.
Studies have shown that adding seat belts to the current seating configuration of a school bus can increase the chance of head and neck injuries.”