In road-transport terminology, a lane departure warning system (LDWS) is a mechanism designed to warn the driver when the vehicle begins to move out of its lane (unless a turn signal is on in that direction) on freeways and arterial roads. These systems are designed to minimize accidents by addressing the main causes of collisions: driver error, distractions and drowsiness. In 2009 the U.S. National Highway Traffic Safety Administration (NHTSA) began studying whether to mandate lane departure warning systems and frontal collision warning systems on automobiles.
There are three types of systems:
Systems which warn the driver if the vehicle is leaving its lane with visual, audible, and/or vibration warnings (lane departure warning, LDW)
Systems which warn the driver and, with no response, automatically take steps to ensure the vehicle stays in its lane (lane keeping assist, LKA/LKS)
Systems which assist in oversteering, keeping the car centered in the lane, and asking the driver to take over in challenging situations (lane centering assist, LCA)