Navigation-system specialist Garmin also sells a portable head-up display called the HUD+. It projects onto your windshield the current speed as well as navigation info to help guide you to your destination. The unit works in conjunction with a navigation app that you download for free with your Apple or Android phone. The information is projected onto a transparent film that’s applied to the windshield, or into an attached reflector lens. And since the unit is not built-in, you can move it to any vehicle. The Garmin HUD+ sells for $180 plus $20 for the charger and $10 for the windshield film. Full details at www.garmin.com.