Usability Study of the Universal Anchorage System for Child Restraints in School Buses and Passenger Vehicles

Christina M. Rudin-Brown

Ergonomics and Crash Avoidance Division
Motor Vehicle Safety Directorate
Andrea Scipione, Joe Armstrong, Gerald Lai, Alice Salway, and Jason Kumagai
CAE Professional Services Canada

March 2007
TP14702 E


Since 2002, Transport Canada has required that all new vehicles and child restraint systems (CRS) be equipped with the Universal Anchorage System (UAS), which includes lower anchorage, and top tether, attachments. Despite being designed to make CRS installation in vehicles easier and with fewer opportunities for misuse, there have been reports that the UAS is not as easy to use, or as effective, as hoped (Arbogast and Jermakian, 2007; Decina, Lococo & Doyle, 2006; Consumer Reports, 2003; Status Report, 2001). To date, however, there have been no systematic or experimental studies evaluating the usability of the UAS.

Based on research demonstrating that small children on school buses are not protected from injury in the same manner as larger children (Legault, 2004), Transport Canada will require, effective April 2007, that UAS anchorages be installed on a proportion of seats in all school buses, allowing for the installation of CRS. The present study, therefore, was designed to assess the usability of the UAS in both cars and school buses. The main objectives of the study were to provide guidance on potential UAS design improvements and to make recommendations concerning labelling and instructions related to the UAS.

Users installed CRS in a car and a school bus using three different types of lower anchorage connectors and top tethers. Surprisingly, many participants were not familiar with the UAS, and believed that CRS should only be installed using the seat belt. Over 40 per cent of participants did not know where the lower anchorage connectors were located in the car. While installation performance using the UAS was generally satisfactory (all v were installed correctly between 70 and 92 per cent of the time), UAS design improvements for both the CRS and the vehicles were identified. A supplementary, informal usability study (Appendix C) done in the school bus identified a number of additional issues relating to the use of CRS in these vehicles. The implementation of the proposed design improvements by CRS and automotive manufacturers should increase the overall usability of the UAS and increase its effectiveness in the event of collisions.

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