It is important that the headlights be aimed correctly to avoid blinding the driver of an oncoming vehicle, which could lead to serious accidents or impair visibility. Headlights should be checked for proper aim every 12 months and whenever a new headlight is installed or front-end body work is done. Earlier model sealed beam headlights have two spring-loaded adjusting screws, one on top for up-and-down movement and one on the side for left-and-right movement, while later aerodynamically styled halogen headlights use one upper adjusting screw for left-and-right movement and an inner corner angle drive mechanism for up-and-down movement. To adjust the headlights, a blank wall 25 feet in front of the vehicle and a level floor are needed. Vertical masking tape should be positioned on the wall in line with the vehicle centerline and the centerlines of both headlights, along with a horizontal tape line referencing the centerline of all headlights. The vehicle should be level, with the gas tank half-full and no unusually heavy load. For low beam adjustment, the high-intensity zone should be set two inches below the horizontal line and two inches to the side of the headlight vertical line, away from oncoming traffic, using the appropriate adjusting screw. With high beams on, the high-intensity zone should be vertically centered just below the horizontal line, keeping in mind that low beams are more frequently used and crucial for driver safety. It is advisable to have the headlights adjusted by a dealer service department as soon as possible.