title: Rear-seat motor vehicle travel in the U.S.: using national data to define a population at risk.
abstract: BACKGROUND
  Recent studies suggest that the relative protection offered by rear seating in motor vehicle crashes has decreased, potentially reflecting disproportionate advancements in front-seat safety technology. Safe adaptation of advanced front-seat restraint systems for the rear-seat environment will require exposure data that are currently unavailable.
  
  
  OBJECTIVE
  This study uses national data to quantify rear-seat occupancy patterns, restraint use, and annual travel exposure in the U.S. in order to support the development of advanced crash protection systems for rear-seat motor vehicle occupants.
  
  
  METHODS
  Data from the 2000-2006 National Automotive Sampling System Crashworthiness Data System and 2001 National Household Transportation Survey were analyzed in 2008 to quantify occupancy patterns (e.g., seat position, restraint use) and annual person-trips for rear-seat passengers in the U.S.
  
  
  RESULTS
  The overall proportion of person-trips by rear-seat occupants is relatively low (12.9%); however national at-risk exposure remains significant (approximately 39 billion annual person-trips). Annual rear-seat travel exposure is similar among children < or = 12 years and adults (18.9 vs 19.1 billion person-trips) despite the fact that children are proportionally much more likely to ride in rear positions (79.3% vs 7.4%). Restraint use among adult rear-seat occupants was also much lower than among front-seat occupants (50.4% vs 82.2%).
  
  
  CONCLUSIONS
  While rear-seat occupancy is relatively low compared with front-seat occupancy at-risk rear-seat travel by both child and adult passengers in the U.S. remains significant. Restraint use by rear-seat occupants is much lower than that among front-seat passengers, particularly among adults and older children, substantially increasing injury risk. Development of future crash protection systems for rear-seat passengers must account for these exposure patterns to ensure safe and effective integration into production vehicles.
authors.affiliation: Department of Emergency Medicine, University of Virginia Health School of Medicine, Charlottesville, Virginia 22908-0699, USA. mtrowbridge@virginia.edu
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Trowbridge
authors.forename: Richard
authors.initials: R
authors.lastname: Kent
mesh_terms: D000063:Accidents, Traffic / Q000517:prevention & control / Q000706:statistics & numerical data*; D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D017278:Air Bags; D001336:Automobiles / Q000592:standards / Q000706:statistics & numerical data*; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018570:Risk Assessment; D012449:Safety; D012622:Seat Belts / Q000706:statistics & numerical data*; D014481:United States; D014947:Wounds and Injuries / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control; D055815:Young Adult