Document GRPE/2014/11 was prepared by the GRPE informal working group on heavy duty hybrids (HDH) to add the test procedure on heavy-duty hybrids to GTR No. 4.

This informal document revises and supplements GRPE/2014/11 in order to align GTR No. 4 and GTR No. 11 (NRMM) in accordance with the latest work of the HDH group. The renumbering of equations, tables and figures, the corresponding references, and the symbols list in paragraph 3.2 has not been completed in this document. This will be done during the final editing of GRPE/2014/11.