Attention Aware not car friendly!
Using my iPhone X is fine but not necessarily for the car...
If you've got attention aware activated and the phone is on the windscreen/windshield directly facing you then the display won't dim as it thinks you're constantly looking at it!
I don't know how you can get round this other than to slightly adjust the position of the phone so it's not facing you... but then if you want to unlock it that won't work.... Doh!!!
iPhone X, iOS 11.1.2