It might also be a DRIVER factor. That driver is driving a Dmax ..but at that same moment and in all probability he could also be driving a Hilux, a Strada, or a Navarra, who, I think can also come out fast if the driver floors it! The point is, the Dmax can be fast. But so are the others as well.
The driver still counts in as a factor out of the many factors to consider when it comes to speed and fuel economy.