title: Crash fatality risk and unibody versus body-on-frame structure in SUVs.
abstract: BACKGROUND
  In crashes between cars and SUVs, car occupants are more likely to be killed than if they crashed with another car. An increasing proportion of SUVs are built with unibody, rather than truck-like body-on-frame construction. Unibody SUVs are generally lighter, less stiff, and less likely to roll over than body-on-frame SUVs, but whether unibody structure affects risk of death in crashes is unknown.
  
  
  OBJECTIVE
  To determine whether unibody SUVs differ from body-on-frame SUVs in the danger they pose to occupants of other vehicles and in the self-protection they offer to their own occupants.
  
  
  METHODS
  Case-control study of crashes between one compact SUV and one other passenger vehicle in the US during 1995-2008, in which the SUV was model year 1996-2006. Cases were all decedents in fatal crashes, one control was selected from each non-fatal crash.
  
  
  RESULTS
  Occupants of passenger vehicles that crashed with compact unibody SUVs were at 18% lower risk of death compared to those that crashed with compact body-on-frame SUVs (adjusted odds ratio 0.82 (95% confidence interval 0.73-0.94)). Occupants of compact unibody SUVs were also at lower risk of death compared to occupants of body-on-frame SUVs (0.86 (0.72-1.02)).
  
  
  CONCLUSIONS
  In two-vehicle collisions involving compact SUVs, unibody structure was associated with lower risk of death both in occupants of other vehicles in the crash, and in SUVs' own occupants.
authors.affiliation: Washington State Department of Health, PO Box 47812, Olympia, WA 98504-7812, USA. Electronic address: eric.ossiander@doh.wa.gov.
authors.forename: Eric M
authors.initials: EM
authors.lastname: Ossiander
authors.affiliation: Department of Epidemiology, School of Public Health, University of Washington, Seattle, WA 98195, USA. Electronic address: koepsell@u.washington.edu.
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Koepsell
authors.affiliation: Department of Biostatistics, School of Public Health, University of Washington, Seattle, WA 98195, USA. Electronic address: bmck@u.washington.edu.
authors.forename: Barbara
authors.initials: B
authors.lastname: McKnight
mesh_terms: D000063:Accidents, Traffic / Q000401:mortality*; D001336:Automobiles; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D012307:Risk Factors; D012449:Safety / Q000706:statistics & numerical data*; D014481:United States / Q000453:epidemiology
keywords: Body-on-frame construction; Compatibility; SUVs; Unibody construction