Head-up display technology made it's way from fighter jets to cars about 25 years ago. I've had head-up displays in my last two cars and find it to be incredibly useful. It projects both the speed you are traveling and navigation instructions on the windshield, although when you are driving it looks like it is about 3 feet in front of your hood.
It makes driving a lot safer because you never have to take your eyes off of the road. However, it is real pricey...we are talking four figures to get the technology in your car. But now there's a game changer. Navigation specialist Garmin is about to release a head-up display for navigation at $129.99. It's simple, small and portable, so it can be used in multiple vehicles.
The Garmin unit is a head-up display unit only. The unit receives the mapping info from your Bluetooth-enabled smartphone running a $29.99 Garmon app (StreetPilot1 or NAVIGON). The projector attaches to your dash and projects the image onto a transparent film on the windshield. The device is currently at the FCC for approval and will be on the market soon.