Final status report on development of a new UN GTR for laboratory measurement of brake particle matter (PM) and particle number (PN) emissions from heavy-duty vehicles. The GTR introduces brake emissions groups based on fundamental design and performance characteristics, defines brake group nominal test parameters by disc or drum diameter, establishes friction braking share coefficients with c-factor = 1 for full-friction braking, specifies required test input parameters including brake system type and filtering systems, prescribes the Worldwide Harmonized Heavy-Duty Brake Cycle (WHBC) comprising 246 brake events over 5:39 hours across urban, rural, and motorway segments, defines PM and PN measurement methodologies using gravimetrical and particle number counter methods, specifies hardware requirements including brake dynamometer, enclosure dimensions of 1950 mm length × 1000 mm height × 700 mm depth with divider plate, sampling tunnel with 300 mm fixed inner diameter, and brake temperature measurement by embedded thermocouples, and includes results of preliminary interlaboratory study.