Crashworthiness of Small Poststandard School Buses (NTSB/SS-89/02)
This study focused on the crash performance of small school buses constructed in compliance with seating Standard 222. There were seat belts at all seating positions. 24 accidents were reviewed. There were a total of 167 occupants, 110 or about 2/3s were seat belted and subjected to crash forces.
During side impact and rollover accidents, protection for seat belted passengers seated between padded seats was excellent. Among these belted passengers; there were no significant abdominal or head injuries. None were thrown from the between the padded seats. This was not the case for the unbelted passengers.
It must be kept in mind that when in a similar collision to a large school
bus, these small vehicles will be subject to greater crash forces. As a
result, the absence of lap belt induced injury in this real world experience
is of major significance.
Of the 43 accidents reported 13 were side impact or non-collision rollover accidents where the injury producing forces were lateral and passenger kinematics were uncomplicated by foreward or rearward components. Accident severity ranged from very minor to extremely
severe. A total of 420 unbelted passengers were exposed and compartmentalization failed 65% of the children. 272 suffered injuries. On the other hand 38 were wearing belts. None of these were injured. 0% were hurt. The seat belts had protected all.
Case 13. Moderate. Multiple left side. Compartmentalization failed. 4 of 5 passengers injured. NTSB determined that lap belts would have prevented 3 injuries.
Case 16. Very Minor Sideswipe. Bus went off road. Compartmentalization failed. All 29 passengers were wearing belts. None injured. NTSB reports that crash was so minor that driver reported that books did not falloff seats. Driver denies making such a statement to investigators. She states that books are carried in knapsacks. All on the bus felt the strong pull of the crash pulse on their seat belts and dispute the very minor classification.
Case 17. Minor Sideswipe. Compartmentalization failed. 5 of 43 passengers injured. 1 suffered brain concussion. NTSB determined that a lap belt would have helped,
Case.18. Moderate. Slow moving train hit rear of bus. Compartmentalization failed. Only 8 of 53 passengers injured because driver insisted that all sit in front of bus, fortunately away from area of impact. .
Case 20. Moderate. Right side then left with partial rollover. Compartmentalization failed. 15 of 17 passengers injured, 5 moderate, 1 serious. NTSB determined that a lap belt could have reduced the severity or the serious injury. The moderate injuries to head, shoulder and extremities caused by children being thrown into sidewalls and windows could have been mitigated by padding of sidewalls.
Case 21. Moderate-Severe. Right side followed by minor left side. Compartmentalization failed. Of the 42 passengers 39 were injured, 4 moderate. NTSB has determined that lap belts would have eliminated 2 pelvic fractures. I head injury was caused by the steel sidewall. Other minor injuries were attributed to contact with parts of the bus interior and/or other occupants. Lap belts and wall padding would have mitigated.
Case 22. Minor. Non collision rollover. Compartmentalization failed. Of 8 passengers 3 suffered minor and 2 moderate injuries. NTSB estimates that lap belts would have prevented 2 of the moderate injuries. The 3 minor injuries caused by being thrown as the bus rolled could have been reduced or eliminated with padding and belts. One child was wearing a seat belt and rode through the rollover uninjured.
Case 23. Minor. Non-collision rollover. Compartmentalization failed. 12 passengers, 2 injured. Girl seated on left side fell across the bus to the right striking a boy seated on the right injuring both. NTSB determined that these injuries would have been prevented by lap belt use.
Case 24. Minor-Moderate. Rollover. Compartmentalization failed. 2 passengers. 1 serious
injury. Young girl who was seated on left side and was flung to the right as bus rolled over. Her right arm went through the window and remained outside as bus slid several feet along gravel roadway. Her arm had to be amputated above the elbow. NTSB admits lap belt would have prevented this serious injury .
Case 25. Moderate. Non-collision rollover Compartmentalization failed. 53 passengers, 36 injured, 4 moderate, Minor and moderate injuries resulted from contact with sidewall and windows. Padding would have mitigated.
Case 26. Moderate. Noncollision rollover. Compartmentalization failed. All passengers were injured, 5 minor 6 moderate. Injuries caused by hitting overhead luggage racks during rollover. Producing vertebral and cervical fractures. NTSB has determined that lap belts would have prevented most of the injuries. Padding would have reduced contact with sidewalls.
Case 27. Moderate. Non-collision rollover. Compartmentalization failed. 47 of 51 passengers were injured. "...all passengers tumbled around in the bus interior. Students mentioned hitting their heads, necks, shoulders and backs during rollover." Incredibly the Board did not feel that lap belts would be of value. They contend without documentation or example that injuries would be the same if lap belted. Applying extremely convoluted reasoning they point out that since some seat cushions dislodged in the accident, "...lap belted students conceivably could sustain more serious injuries should cushions come off during rollover. Since they then will impact the exposed seat rails with their "tail bones" or fall between the railings." This conjecture is patently absurd. Belted students held on their seats by their restraints would hold the cushions in place and ride through the accident uninjured with their "tail bones" intact.
Case 28. Moderate. Non-collision rollover. Compartmentalization failed. Of 22 passengers all were injured, 1 moderate, 1 serious injury. Most serious was a liver injury. NTSB has determined that lap belts might have reduced this serious as well as the moderate injury. Students reported that they struck the roof, windows, seat backs and fell on one another. The Board speculates that injuries "...probably occurred as the bus rolled over and the flailing arms and legs struck seats, windows and each other. Head contusions were common. The failure to remain compartmentalized should be obvious.
Case 29. Moderate-Severe. Non-collision rollover. Compartmentalization failed. Of 33 passengers, 24 minor, 3 moderate injuries with 4 ejections. Injuries included vertebral and clavicular fractures and a severe laceration. The bus did a 360 degree rollover. NTSB has determined that lap belts would have prevented ejections
Case 30. N.A. Frontal Case 31. N.A. Rear
Case 32. N.A. Frontal Case 35. N.A. Frontal Case 36. N.A. Frontal
Case 37. N.A. Multiple collision Case 38. N.A. Head on Case 40. N.A. Rear
Case 41. N.A. Frontal
Case 33. Moderate. Left rollover. Compartmentalization failed. Of 9 passengers, the only injury was sustained by the only passenger who was not wearing a seat belt. NTSB agrees that the remaining belted passengers were spared injury because of belt use.
Case 34. Moderate. Left side, then rollover. Compartmentalization failed. Of 17 passengers 16 were injured. They were thrown from their seats onto ceiling and/or seats and other passengers. NTSB agrees that lap belt~ might have reduced the number of injuries.
Case 39. Severe. Side. Compartmentalization failed. Of 7 passengers 3 received minor, 2 moderate and 1 fatal injuries. Fatality was seated right rear just behind impact area and suffered a closed head wound, abdominal trauma and a fractured pelvis. Accident was probably not survivable.
Case 42. Extremely Severe. Right side rollover. Compartmentalization failed. Of 26 passengers 23 sustained minor, 1 moderate and 2 serious injury. One serious injury occurred to a child seated in the last row as her head hit the rear door behind. A seat belt would not have helped, however 10 year old 'iirl seated behind the driver was thrown head-first toward the right side of the bus. She sustained head trauma including a depressed skull fracture. NTSB determined that a seat belt would have prevented or mitigated this injury .The remaining children suffered multiple lacerations, cuts, abrasions, bruises and contusions to the head, arms and legs as they were thrown about during tie impact and subsequent rollover. Lap belts and sidewall padding would have reduced injury.