Headlamp unit failure on this vehicle. water intrusion into the unit causing moisture buildup with resulting cloudiness, calcium like etching, and spider web-like cracking of the plastic lens. poor uv sun blocking ability of the plastic lens to retard yellowing & clouding. these defects in the headlamp unit construction present a safety hazard issue at night as it reduces the effectiveness and ability to project light beam at levels necessary for clear visual field. this vehicle has incurred complete headlamp unit assembly replacements to both driver & passenger sides twice since vehicle placed into new service in 2009. it appears the cheap plastic lens covers used in manufacturing is the culprit. use of glass for lens would eleminate these problems as glass does not deteriorate with sun or moisture.