This study analyzes the real-world emissions of seven Euro VI-D trucks and evaluates the avenues for extending the in-use PEMS test provisions to better capture a wider range of frequently occurring conditions in real operation. The analysis finds that urban operation is responsible for 50% to 90% of total NOx emissions from the trucks tested. However, the Euro VI ISC methodology to assess compliance, as set by implementation steps D and E, does not capture the real-world NOx performance in cold-start conditions and low-load or low-speed operation typical of urban driving.