Research has shown that the more sophisticated and reliable automation becomes, the harder it is for a driver to remain vigilant.
The systems that are currently available either assume the driver is paying attention when his or her hands are on the wheel or use a driver-facing camera to determine if the driver’s head is oriented toward the road, but neither is foolproof.
The researchers recommend employing multiple monitoring methods. When the driver monitoring system detects that the driver’s focus has wandered, that should trigger a series of escalating attention reminders: Visual, Audible, Physical Alerts and Pulse Braking. No manufacturer currently incorporates all these measures
Read the article at IIHS.