What school bus safety concept uses tall padded seats as protective barriers?

The school-bus safety concept that uses tall padded seats as protective barriers is compartmentalization. Instead of relying primarily on seat belts, the seating area is designed to contain passengers during many front- and rear-impact crashes.

Compartmentalized seats have energy-absorbing padding, high seat backs, and closely spaced rows. In a crash, a passenger moves into the padded back of the seat ahead, while the surrounding rows help distribute forces across a protected compartment. The design grew from UCLA research in the 1960s and became part of U.S. school-bus requirements through Federal Motor Vehicle Safety Standard 222 in 1977.

The concept is not the same as a roll cage, lap restraint, or an airbag. It is a passive restraint system, and its protection is strongest in front-to-back impacts. Side collisions, rollovers, and ejection risks are limitations, which is why some jurisdictions have added lap or three-point belts.