For safety reasons Toyota does not want you concentrating on the Nav screen rather than focusing on the road ahead. At first I was not sure I understood this but after all of the media hysteria, claims and lawsuits against Toyota for a lot of driver error allogations, I certainly understand now. There are two work-arounds. 1) Plan your trip ahead of time and map it out before you leave or 2) Use the Voice Commands while driving.
This seems to be a common feature for American NAV systems. Even the stand alone models do this - my husband's Tom Tom reacts the same way. I actually prefer this safety feature - it provides one less distraction to drivers. I've already been hit by someone who was texting while driving!
There are several ways around it - check these threads: (Warning; they are LONG) If you're an electronics hobbyist, here's a relatively easy circuit that will do it. The reminder of how/where to connect is elsewhere in the same thread: http://priuschat.com/forums/gen-iii...erride-speed-sensor-bypass-15.html#post959286 If you'd prefer a plug-and-play unit, here's an option: http://priuschat.com/forums/gen-iii...navi-hack-installed.html?highlight=navigation BTW, there is no software or DVD "hack" at this point, for this NAV. Hardware solution only. Enjoy..
