Driver Drowsiness Detection
Driver drowsiness detection looks for patterns associated with fatigue and warns the driver, but it cannot determine with certainty whether a person is safe to continue driving.
Sensors used
Drowsiness detection commonly uses an interior Cameras or near-infrared Infrared and thermal cameras channel to estimate eyelid closure, gaze and head pose. Some systems also infer possible fatigue from steering corrections, lane position or control inputs using the motion information described in Positioning and Vehicle Motion.
These signals are indirect and can disagree. Sensor Fusion covers confidence management, while Calibration, Cleaning and Sensor Health covers blocked views, eyewear, cabin lighting and sensor alignment.
Indirect detection
An indirect system infers fatigue from vehicle and control behavior. Inputs can include:
- steering corrections and periods without steering input;
- lane position and lane-departure events;
- trip duration and time of day;
- turn-signal, pedal and other driver inputs.
These systems can work without an inward-facing camera, but unusual road conditions or an individual's driving style can resemble fatigue.
Direct detection
A camera-based driver-monitoring system can observe eyelid closure, blink patterns, gaze and head pose. Direct observation can identify some forms of drowsiness earlier and distinguish them from a steady steering style.
Sunglasses, low light, camera obstruction, face coverings and seating position can reduce confidence. The vehicle should communicate when monitoring is degraded.
Warning and response
The usual response is visual and audible advice to take a break. Some systems also use haptic feedback or increase the sensitivity of lane and collision warnings.
A function that slows or stops the vehicle after repeated non-response is Unresponsive Driver Assist. It depends on steering and braking systems and should not be described as an action performed by drowsiness detection alone.
European requirements
The EU General Safety Regulation includes driver drowsiness and attention warning among required safety systems for new vehicles under its implementation timetable. It also distinguishes advanced driver-distraction warning, which addresses attention to the traffic situation.
Consumer evaluation can examine detection quality, warning timing, direct monitoring and the ease with which the system can be misused. These are especially important when sustained Level 2 assistance reduces the amount of visible control input a driver needs to make.
Driver responsibility
A coffee-cup symbol is not a medical assessment. When fatigue appears, the safe response is to stop at a suitable place and rest. Opening a window, increasing audio volume or relying on lane support does not restore alertness.