Objective: This study aims to provide population estimates of incorrect restraint use among children aged 0-12 traveling in cars in New South Wales (NSW) and describe the errors occurring in different restraint types.
Methods: Observations of randomly selected children and restraints were conducted in situ by trained researchers at sites statewide. Observation sites were randomly selected using a multistage stratified sample plan. Restraint use errors were recorded and analyzed by severity of error and restraint type using complex survey analysis techniques.
Results: One in two children was incorrectly restrained, and 38 percent in a serious manner. Multiple errors were common (31% of children). Both installation and "securing" errors were common, with installation errors more common in convertible restraints (rearward-facing/forward-facing restraints and forward-facing restraints/booster seats) than single-mode restraints (odds ratio [OR] 4.3; 95% confidence interval [CI] 1.7-10.8). Multiple errors were more common in convertible restraints (OR 3.6; 95% CI 1.9-7.0). The most frequently observed errors were excessive seat belt slack (>25 mm), incorrect belt routing, nonengagement of the seat belt buckle, very loose harness (>25 mm slack), harness off the shoulder, nonuse of belt guides, sash belt worn under the arm, and very twisted harnesses and belts (>2 twists). For rearward- and forward-facing restraints the highest priorities in terms of frequency and degradation in crash protection are errors related to harness use. For booster seat users the most important are those related to correct seat belt and belt guide use. For seat belt users, errors related to correct positioning of the sash belt are key.
Conclusions: The results indicate that many errors are currently occurring in the way children are using restraints, as well as problems associated with the way child restraint systems are installed in vehicles. Incorrect use is particularly problematic in convertible restraints (rearward-facing/forward-facing restraints and forward-facing restraints/booster seats). Different priorities, in terms of the frequency and potential degradation in crash protection due to incorrect use for different restraint types, exist and these are important for those designing countermeasures to this problem.