Display a map overlay indicating the rated and the typical range based on main roads.
The BMW i3 shows such a feature in the image below showing EV range and additional range with the gas range extender.
Moderator: While the i3 has a very limited range, this information becomes far more critical. With every Tesla offering 2 to 4 times the range, it’s less important. The navigation system does show the estimated percent battery left at a destination.