Vehicle LATCH system features associated with correct child restraint installations
Authors: Kathleen D. Klinich, Carol A.C. Flannagan, Jessica S. Jermakian, Anne T. McCartt, Miriam A. Manary, Jamie L. Moore, Joann K. Wells.
Objective: Lower Anchors and Tethers for Children (LATCH) was intended to standardize the attachment between child restraints and vehicle seats. However, LATCH implementations vary, resulting in different ease-of-attachment of child restraint connectors. Identifying vehicle characteristics associated with correct child restraint installations can provide guidance for designing vehicle LATCH systems that increase the correct child restraint installation. Methods: LATCH system and other relevant vehicle characteristics were documented in 98 top-selling 2010-11 vehicles. These features, together with proposed LATCH usability recommendations from the International Standards Organization and Society of Automotive Engineers, were used to select 12 vehicles for volunteer testing with a range of LATCH system characteristics. Thirty-six volunteers were assigned to four groups; each group tested three vehicles, four child restraints (infant, rear-facing convertible, forward-facing convertible, and combination seat), and two installation methods (lower anchors and seat belt) in a split-plot experimental design. Mixed-effects logistic regression models were used to identify predictors of tight installation and correct lower anchor use. Results: Vehicle survey results indicated that most vehicle manufacturers provide the minimum number of LATCH hardware locations required by regulation. Among 21 vehicles with a third row, four had no tether anchors and 11 had no lower anchors in the third row. Study volunteers correctly used the lower anchors in 60% of LATCH installations and used the top tether in 48% of forward-facing installations. When the tether was used, use was correct in 46% of trials (22% of all forward-facing installations). Only 13% of all trials had completely correct child restraint installation (correct use of lower anchors or seat belt, correct tether anchor use, tight seat installation, and correct installation angle). Tight installation was 3.3 [...]