The **LDW (Lane Departure Warning)** is a safety system that warns the driver when they unintentionally change lanes. This system is especially useful for preventing accidents caused by **drowsiness** or **fatigue**, as these states can cause the driver to leave their lane without realizing it.

- **Drowsiness** can cause the driver to lose concentration, see blurry, or even unintentionally leave their lane.
- **Fatigue** also affects concentration ability and can cause the driver to take longer to react, increasing the risk of unintentionally changing lanes.

The LDW uses **sensors** to detect if the vehicle is leaving its lane and alerts the driver through visual, auditory, or steering wheel vibrations. This allows the driver to correct their trajectory and avoid accidents.

Therefore, the LDW is crucial for warning the driver when they change lanes unintentionally, helping to maintain road safety.