The difference is interaction. I haven't ever been in a car with a windshield HUD, but I assume it doesn't require specific driver interaction to use. Using you

The difference is interaction. I haven't ever been in a car with a windshield HUD, but I assume it doesn't require specific driver interaction to use. Using your smartphone while driving is also very illegal and can get you an expensive ticket. Anything that shifts your attention away from the road is dangerous, even if it's "in front of you". Passive information is very different from interactive menus.