Progress report on development of a Global Technical Regulation for brake emissions testing. The document presents bracketed parameters under development including brake test temperature measurement, sampling plane positioning, brake enclosure dimensions, payload factors, and emission factor calculations. It outlines the structure of the informal document based on UN R179, defines endurance braking systems and electric regenerative braking, presents C-factor methodology for primary and secondary endurance braking, and describes conformity of production procedures and next steps including removal of brackets and round-robin data analysis.