New safety tech is popping up everywhere on cars today, and two related systems you may have encountered are lane departure warning (LDW) and lane keeping assist (LKA, or sometimes LKAS). LDW is a system that alerts the driver when the vehicle is about to leave its current lane. LKA builds on LDW by actively steering the car back into the correct travel lane. A full 37 percent of fatal accidents have to do with accidental lane departure, according to NHTSA, so these systems are both useful and important, if sometimes annoying.
LDW usually uses a beep, vibration or visual cue to let the driver know the tires have crossed, or are about to cross, the lane marker if the driver hasn’t activated his or her turn signal. Most use cameras that recognize the white and yellow lines to judge when to give that warning. Some also use laser sensors mounted in the front of the vehicle, and still others use infrared.
LKA goes a step further and takes control of the wheel using the electric power steering system to keep the vehicle in its lane. Some systems also work with the adaptive/radar cruise control for added safety. Like LDW, the systems are supposed to disengage when the turn signal is on, or when the driver is accelerating for an overtake.
Some systems are reactionary; they turn the wheel after the car has left the lane. Others are proactive, keeping the car centered in the lane. The latter system is sometimes noted by a third acronym: lane centering assist, or LCA.
Though helpful, all lane monitoring systems are limited by the visibility of the lane markings, particularly in construction areas and during bad weather. They’re safety aids, not self-driving tech, so make sure you keep your hands on the wheel and eyes on the road even if your car is equipped with LDW and LKA.