The lane departure warning (LDW) system is a warning system that alerts drivers if they are drifting (or have drifted) out of their lane or from the roadway. This warning system is designed to reduce the likelihood of crashes resulting from unintentional lane departures (e.g., run-off-road, side collisions, etc.). This system will not take control of the vehicle; it will only let the driver know that he/she needs to steer back into the lane. An LDW is not a lane-change monitor, which addresses intentional lane changes, or a blind spot monitoring system, which warns of other vehicles in adjacent lanes. This informational report applies to original equipment manufacturer and aftermarket LDW systems for light-duty vehicles (gross vehicle weight rating of no more than 8500 pounds) on relatively straight roads with a radius of curvature of 500 m or more and under good weather conditions.