Scientific methodology and engineering techniques were applied to a series of three automobile rear-end collision experiments to provide data relating to seat, seat backrest, and head-restraint design. Five seat back heights and four seat back strength values were studied in connection with their practicality and relative protective features, when subjected to a 55 mph rear-end collision exposure. These research data provide a basic reference system of high-speed collision performance for seat designs with respect to occupant size and proximity to injury producing structures. Additionally, methodology, instrumentation, and related equipment required for post-crash fire studies were included in experiment 106, providing what is believed to be the first published data on the precise time-related events associated with collision-induced passenger car fires. Design revisions suggested by these findings are discussed.