Sunscreens for cars?
Why not? Just push a button (or turn a crank if you're old-fashioned) and have reflecting screens drop down to cover the windows. I dare think they would be more appreciated than GPS.
This is wondered by someone who found the interior of her car at 148* --- interior screen over front windshield but other windows just absorbed all those solar rays. Yes, I actually burned my hand on the metal clasp of the seatbelt.