Proposal to establish a UN Global Technical Regulation for measuring brake particulate matter and particle number emissions from heavy-duty vehicles. The regulation defines laboratory test procedures using a brake dynamometer and the Worldwide Harmonized Heavy-Duty Vehicles Brake Cycle (WHBC), encompassing 20,353 seconds with 246 brake events across three driving segments. Tests require brake bedding with six WHBC repetitions, followed by emissions measurement. Laboratories must measure PM10 and PM2.5 mass gravimetrically and total and solid particle numbers (TPN10, SPN10) using particle counters. Technical specifications cover brake enclosure design, sampling tunnel configuration, climatic control, instrumentation calibration, and data reporting requirements to ensure reproducible and comparable brake emissions testing across regions.