Child passenger restraints in relation to other second-row passengers: an analysis of the 2007-2009 National Survey of the Use of Booster Seats.

OBJECTIVE Child restraint systems (CRS) are increasingly being designed to accommodate larger children and to mitigate side impact injuries. Little is known about the impact of CRS on the safety of other vehicle passengers due to limitations of existing crash databases. This study provides the first assessment of the seating positions occupied by child passengers and the relationship between CRS and other second-row passengers in a national sample of vehicles transporting children. METHODS A secondary analysis was conducted of data from the 2007-2009 National Survey of the Use of Booster Seats (NSUBS), a direct in-vehicle observational study of child passenger restraint use. Passengers riding in the same vehicle were identified and passenger position was determined. Vehicles with second-row child passengers were included in analyses of seat positions occupied by child passengers with and without CRS. Frequency counts for the different combinations of CRS and passengers in second rows were calculated. RESULTS Of the 17,065 vehicles observed in 2007-2009 NSUBS, 14,506 (85%) vehicles contained at least 1 child passenger in a second row that contained no more than 3 total passengers. Of these 14,506 vehicles, 55 percent contained a lone child passenger in the second row. A CRS was in use in 4656 (59%) of the 7949 vehicles with a lone child passenger in the second row compared to 4077 (62%) of the 6557 vehicles with multiple passengers in the second row (P < .001). A passenger was adjacent to a CRS within 1333 (33%) of the 4077 vehicles containing a CRS in the second row. There were 3 second-row passengers in nearly 1 in 5 vehicles containing a CRS in the second row. CONCLUSION Adults and children not using CRS are frequently seated in vehicle second rows adjacent to a child restrained in a CRS. These findings should be used to inform the regulation, design, and testing of CRS and to determine the risks of larger CRS designs to other passengers seated in the same vehicle row relative to the benefits of the CRS for the passenger it restrains.