The Haddon matrix, a tool for investigating severe bus and coach crashes

• Objective: The aim of the study was to use the Haddon matrix to analyse crash and injury mechanisms in a severe coach crash, to investigate if a safety belt would have reduced injuries, and highlight the triage problem in a mass casualty situation during severe circumstances. Methods: A specific coach crash was chosen as the subject for the case study. All 34 occupants on board were interviewed about the crash, their injuries, and how they sustained their injuries. Medical records concerning ambulance and hospital treatment have been examined. Police reports and other documents concerning the vehicle, weather conditions and the road have been examined. The materials were structured in different cells according to Haddon's matrix. Results: The coach went off a road via a guard-rail and landed on the right side, in a 90° position right across a small river. The main reason for the coach to deviate from the road was strong and gusty side winds imposing lateral forces on the coach, making steering impossible. The impact from the crash was greatest in the front part of the coach, as this part fell 3 metres from the bridge guard-rail down to the river bank. The most frequent injury mechanism was that occupants were hit by other falling occupants. Most occupants would have benefited from having worn seat belts. Ten ambulances and one helicopter from different locations were called upon and the first ambulance arrived 30 minutes after the alarm (a 67-km drive). The helicopter, with an anaesthetist on board, arrived after 1 hour and 20 minutes (a 120-km flight). Nine occupants with moderate injuries and 10 seriously or severely injured occupants were transported by ambulance or helicopter to the hospital. Fifteen occupants, triaged as priority 3, were transported by a chartered coach to hospital where they arrived after about 3 hours. Conclusion: If 100% of the occupants had used a two-point belt, about two-thirds of the injured occupants with MAIS 2+ injuries would have sustained an injury reduction. A further injury reduction by roughly 20% could have been achieved by shifting from two-point belts to three-point belts. Triage of injured occupants could be different from normal practice because of the limited space inside a coach, and the use of ordinary equipment is not always possible inside a crashed vehicle. The fact that most of the side windows remained in position after the crash probably prevented many occupants from serious and fatal injuries caused by ejection or partial ejection.

Nyckelord

Haddon's matrix

bus

coach

injuries

prevention

severe crash

mass casualty

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