Overview of TU Graz and TNO evaluation of hardware-in-the-loop simulation methodologies covering the test cycle and vehicle related parameters, harmonisation with CO2 test methods, inclusion of power take-off, and worldwide harmonized vehicle cycle weighting factors.

Progress report on the effort to establish provisions for heavy-duty hybrid vehicles in GTR No. 4, prepared for presentation to the June session of the Working Party on Pollution and Energy (GRPE).