Proposal to clarify the definition of “Option” as used within Global Technical Regulations and to introduce the concept of “Alternative”. In principle, the proposal seeks to distinguish between protocols for the same requirement that allow divergent compliance thresholds (e.g., differing stringency) and those that provide equivalent assessment of performance through different means. “Option” would refer to the former while “Alternative” would refer to the latter. In the case of one or more options, the proposal would require Contracting Parties to work towards the elimination of the divergent performance requirements.