No, no, no not drivers. Passengers.
The system is called Kuruma de DS (loosely, "Use the DS in the Car"). It allows passengers to use the Nintendo DS to input destinations, and it gives map and even sightseeing info. You can save places where you've been on your DS, too.
The Kuruma de DS game card is Bluetooth enabled, allowing DS owners to easily pair the gaming handheld with the car. Then, it's ready for remote control use.
The interface, which features Nintendo Mii characters, might be a tad more user friendly for those more familiar with a DS. There's even a neat little DS speedometer.
With Kuruma de DS, you can also take quizzes and even pipe the DS's sound through the car's speakers.
This sort of in car amusement doesn't come cheap. The top end Smart Navi is ¥206,850 (US$2,586). Kuruma de DS must be purchased separately through Toyota for ¥7,329 ($92)—and that doesn't include the price of an actual DS (assuming you don't own one). All this makes the Kuruma de DS a pricey remote!