I am nervous about all this HUD idea. Firstly they are NOT actual HUD the way it works in the scenarios described, it is NOT pointing where your head is looking and the focal distance is NOT where is your obstacle.
So instead of looking to the sides for pedestrians, cyclists, vehicles, you are looking AT the item on your dashboard.
Instead of focusing at the objects you are focusing AT an item about 2 feet from you.
So what about most people aged 50+ who cannot focus both short and long distance. They often either can focus short distance OR long distance and if seeing an item on the dashboard need glasses which then they must remove to see real actual items they need to see to drive safely.
Then there is cognitive issues, if you are talking with someone you are thinking and listening other than about your driving.
This is all a net negative safety issue easily.
You are driving a roughly 1 Ton lethal machine at speed. Just do that. Nothing else.
I feel this about solving the minor issue of looking down, but the big issue is you are caring more about items we were all quite capable of not worrying about for decades between invention of the car and current mobiles, than you are caring about other people, your responsibility to not kill them.
Selfish stupid people. Turn your mobile off and do driving, just driving.
OR kill someone. And then call it an "accident".