The findings of an investigation conducted as a result of 4 fatal accidents involving non-conforming buses used to transport school children (NBTSC). The investigation identified safety issues in these areas: adequacy of occupant crash protection and crashworthiness of NBTSC; adequacy of State reg. and guidelines governing NBTSC; and adequacy of State laws governing the use of restraint systems in NBTSC. Appendices: Fed. motor vehicle safety standards for buses; history of safety recomm. on school bus crashworthiness and operations; injuries; guideline for the safe transport. of pre-school children in school buses; and status of Safety Recommendations on Child Restraining Systems.