during the wltp the impact of the model’s optional equipment is also considered. in this way the tests reflect better the emissions of individual cars, and not just the one with the standard equipment (as it was for the nedc cycle). in fact, for a same car, the homologation procedure needs two measures: one for the standard equipment and the other one for the fully equipped model. this takes into account the effect on vehicle’s aerodynamics, rolling resistance and change in mass due to the additional features.