Many new cars have such systems, often styled Drowsy Driver Alert or some similar thing. Subaru, for instance, calls their system EyeSight. Computer eyes monitor your eye movements for evidence of distraction or fatigue, according to some programmed-in metric. If the computer decides you aren’t focused on the road, it triggers a cup of coffee icon that you can see – lit up in the dash – along with a “suggestion” you rest rather than drive.