During 1993, an ad-hoc working group of the GRSP, addressing ECE Regulation 44 (Child Restraint Systems), decided to propose the addition of a `Group 0+' to this regulation. This group of restraints concerns the maximum size/age/weight of children to be carried in a rearward facing child restraint system that can be held by a conventional 3-point belt system in front passenger car seats. The working group decided that for the evaluation of these type of (IRSs, an 18-month-01d dummy was needed. On this basis, the TNO Crash-Safety Research Centre, together with Ogle Design Ltd, started to work on a new child dummy:​ the TNO P1½.

In this paper, the development and the design of this new prototype dummy are presented and the rationales behind its design are discussed. Based on regulatory and research applications of the P1½, performance specifications are set up.

The most important specifications concern the anthropometry and biofidelity of the new dummy. In addition other characteristics (repeatability, reproducibility, durability, etc.) have been taken into account during the design process. Using the latest anthropometry data available, incorporating enhanced instrumentation and applying new materials to improve biofidelity, have provided an advanced child dummy design.