The document outlines work priorities for UN GTR 21, 22, and 25 amendments. UN R21 Phase 4 will address fuel-cell electric vehicles, measurement alternatives for integrated systems, test method efficiency, and alignment with UN R177. UN R22 Phase 4 will explore conditioning cycles, readiness monitors, certified range performance requirements, and alignment with UN R154-04 and UN R83-09. UN R25 Phase 3 will consider Annex 2 amendments, virtual distance verification, minimum performance requirement thresholds by vehicle category, and alternative test methods.

Proposal to amend UN GTR No. 21 on determination of system power of hybrid electric vehicles and pure electric vehicles having more than one electric machine for propulsion. The amendment introduces a consolidated reference point concept for identifying where mechanical power is first produced from stored energy in electrified powertrains. Two test procedures (TP1 measuring electrical power and engine parameters; TP2 measuring torque and speed at axles) are defined to determine comparable vehicle system power ratings. Key modifications include requirements for manufacturers to provide verifiable energy conversion factors (K factors), hybrid power flow descriptions, and identification of applicable reference points. Testing involves repeated maximum power measurements on dynamometers at fixed speeds with specified accuracy requirements for instrumentation.