Driver drowsiness detection

Driver drowsiness detection is a car safety technology which helps prevent accidents caused by the driver getting drowsy. Various studies have suggested that around 20% of all road accidents are fatigue-related, up to 50% on certain roads.
Some of the current systems learn driver patterns and can detect when a driver is becoming drowsy.
Technology.
Various technologies can be used to try to detect driver drowsiness.
Steering pattern monitoring.
Primarily uses steering input from electric power steering system. Monitoring a driver this way only works as long a driver actually steers a vehicle actively instead of an automatic lane-keeping system.
Vehicle position in lane monitoring.
Uses lane monitoring camera. Monitoring a driver this way only works as long a driver actually steers a vehicle actively instead of an automatic lane-keeping system.
Driver eye/face monitoring.
Uses computer vision to observe the driver's face, either using a built-in camera or on mobile devices.
Physiological measurement.
Requires body sensors to measure parameters like brain activity, heart rate, skin conductance, muscle activity.
Regulation.
In European Union, regulation (EU) 2019/2144 regulates the driver monitoring system.