The study encompasses occupants of all ages, but focuses on children (2–14 years old, an age spread chosen to be consistent with other safety research and the group with the highest occupancy rates) and elderly occupants (over 55 years old) in rear seat positions in passenger cars. The statistical study reported here undertook to quantify the effectiveness of rear center lap belts versus rear outboard lap/shoulder belts in frontal and side-impact non-rollover crashes. In this paper, the complex issues and controversies surrounding the injury experience of center rear seat occupants in lap belts (particularly as opposed to outboard rear seat occupants in lap/shoulder belts) are examined. (1989) found that significant injuries occurred in 41% of side impacts and 15% of frontal impacts for children 4 to 9 years old. A key research finding was that “Putting the seatbelt under the arm or behind the back and poor belt fit contributed to some abdominal injuries in children” (POWMRI, 2005: p. Recently, the Prince of Wales Medical Research Institute (POWMRI) performed a comprehensive study of crash injury to children and observed: “an alarming number of children are being put at risk through the improper use of seat belts and child restraints” (POWMRI, 2005: p. A separate study found increases in the use of booster seats and child restraints with harnesses from 1999 to 2002, but notes that a substantial number of children in such restraints exceed the manufacturer’s recommended weight limits and concludes “substantial inappropriate restraint still remains and continued investment in outreach efforts is necessary” ( Winston et al., 2003: p. (2000) found that 83% of children between ages 4 and 8 are inappropriately restrained in adult seat belts. In addition, several studies have observed improper or age-inappropriate belt use by children in lap or lap/shoulder belts ( Green, 1986 German et al., 1999 Winston and Durbin, 2000 Durbin et al., 2003 Simpson et al., 2002). In addition, many parents and caregivers prefer the rear center position because it is easier to keep an eye on the child.
The outboard seating positions are not as safe because in the event of a side-impact crash, the outboard location directly behind the driver or passenger seat is more vulnerable if one side is hit because of its proximity to the point of impact. (1999) examined Utah crash records to develop logistic regression models and concluded that the rear seat offers a significant protective effect and that restraint use enhanced this effect. (1998) examined the children’s risk of dying in crashes by seat position and belt use and concluded that children were about 10–20% less likely to die in rear center than in rear outboard positions. Evans and Frick (1988) examined fatal data and concluded that unbelted rear center occupants (older than 15) had a 15% reduction in mortality risk compared to unbelted rear outboard occupants. Partyka (1988) estimated that rear seating lowered fatal risk for children (ages 0–4) by 26%.
While studies have shown that rear outboard belts are highly effective in reducing fatalities and injuries to children and adults ( NHTSA, 1999 Padmanaban and Besuner, 1999 Padmanaban and Davis, 1999 Padmanaban, 1998 Warner, et al., 1997 Padmanaban, 1992 and Padmanaban and Ray, 1992), very few studies address the effectiveness of belts in rear center seats. The center position has long been served by a lap-only belt for several reasons, including that this restraint system configuration most easily accommodated a child safety seat in rear center in the early 1980s and 1990s. As of December 2004, 23% of new passenger cars and 51% of new vans and light trucks were equipped with lap belts in rear center seats. In December 2004, the National Highway Traffic Safety Administration (NHTSA) announced a final rule that rear center seats in all new passenger vehicles be equipped with lap/shoulder belts. 771) opined that “the best advice is to seat the child in the center position whenever possible and to ensure that age-appropriate restraints are used.” In the last few years, several studies have been published examining the effectiveness of various types of rear seat restraint systems for children, including booster seats and child safety seats ( Durbin et al., 2003 NHTSA, 1999, 2002 Winston et al., 2000). For decades, safety researchers around the world have agreed the rear seat environment is the safest for children ( Braver et al., 1998 Berg et al., 1999 NHTSA, 1999).