title: Factors associated with mortality in rear-seated adult passengers involved in fatal motor vehicle crashes on US roadways.
abstract: BACKGROUND
  Recent efforts to pass rear seat belt laws for adults have been hampered by large gaps in the scientific literature. This study examines driver, vehicle, crash, and passenger characteristics associated with mortality in rear-seated adult passengers.
  
  
  METHODS
  The Fatality Analysis Reporting System (FARS) 2010 to 2011 was used to examine motor vehicle occupant mortality in rear-seated adult passengers 18 years and older. Side crash vehicle safety ratings were assessed in a subset analysis of vehicles struck on the same side as the rear-seated passenger. Multilevel logistic regression models used SAS GLIMMIX.
  
  
  RESULTS
  Of the 7,229 rear-seated adult passengers, 2,091 (28.9%) died. Multivariable predictors of increased mortality were advancing passenger age, younger driver age, excessive speed, ejection, being unbelted, rear impact, and same-side crash. Belt use was associated with a 67.0% reduction in total mortality. Despite this, belt wearing was low (48.1%) and differed by seating position, with less than one third of middle-seated passengers belted. Multivariable analysis showed mortality to be nearly three times higher in same-side crashes than other impact locations (odds ratio (OR) = 2.76, 2.22, 3.44). In a multivariable subpopulation analysis of same-side crashes, right-seated passengers had an increased mortality (52.7% vs. 43.2%, p < 0.01) compared to left-seated passengers (OR = 1.55, 1.02, 2.36). Vehicle side crash safety ratings, available for 27.7% (n = 172) of same-side crashes, were not predictive of mortality.
  
  
  CONCLUSIONS
  Except for same-side crashes, seat belts were associated with significantly lowered mortality. Despite this, seat belt wearing was low and represents one of several areas where further improvements in mortality might be realized.
authors.affiliation: Department of Epidemiology, Columbia University, 722 West 168th St., New York, NY, 10032, USA.
authors.forename: Eli
authors.initials: E
authors.lastname: Raneses
authors.affiliation: Department of Epidemiology, Columbia University, 722 West 168th St., New York, NY, 10032, USA. jp376@cumc.columbia.edu.|Department of Health Policy and Management, Columbia University, 722 West 168th St., New York, NY, 10032, USA. jp376@cumc.columbia.edu.|The Center for Injury Epidemiology and Prevention at Columbia, Columbia University, 722 West 168th St., New York, NY, 10032, USA. jp376@cumc.columbia.edu.|Mailman School of Public Health, Columbia University, 722 West 168th St., New York, NY, 10032, USA. jp376@cumc.columbia.edu.
authors.forename: Joyce C
authors.initials: JC
authors.lastname: Pressley
keywords: Elderly passengers; Mortality; Motor vehicle crashes; Point of impact; Rear-seated passenger mortality; Seat belts; Seat position; Side crash test ratings