This paper describes the development, validation and application of a usability or “ease of use” rating system for child restraints and the design changes that have evolved.

The rating system was developed in response to concerns about the high incidence of child restraint misuse and the potential for reduced protection during a collision. The objectives were to help consumers choose child restraints that are easier to use and to encourage manufacturers to improve the usability of their products.

A research program to develop the rating system was undertaken by RONA Kinetics with the support of the Insurance Corporation of British Columbia in Canada. It included participation by members of the ISO child restraint working group, regulatory authorities, vehicle and child restraint manufacturers, child passenger safety technicians, IIHS and consumers. A sample of some 30 child restraints (from N. America and Europe) was used to identify key child restraint use features that were ranked according to the risk of injury if misused. Objective criteria and tests for rating the individual features and a method for calculating the rating scores were developed.

The rating system was first used to rate 80 child restraints for ICBC consumer guides. It is the basis for the NHTSA child restraint ease of use rating program. It is being used in new ISO work related to the usability of ISOFIX (LATCH/UAS) features. Its current use and areas in which the rating system may be upgraded are considered.

The rating system provides an objective means of evaluating the usability of child restraints. It addresses features related to the safe use of child restraints that are not included in current regulations. Since its application, child restraint manufacturers have improved the usability of their products thereby reducing the risk of misuse and increased child passenger protection.