2015 Buick Regal Owner Manual - Page 240

Driving and Operating When the System Does Not Seem to Work Properly The system may not detect lanes as well when there are: . 9-59 Fuel Use of the recommended fuel is an important part of the proper maintenance of this vehicle. When driving in the U.S. and Canada, to help keep the engine clean and maintain optimum vehicle performance, we recommend using TOP TIER Detergent Gasolines. See www.toptiergas.com for a list of TOP TIER Detergent Gasolines. Close vehicles ahead. Sudden lighting changes, such as when driving through tunnels. Banked roads. When LDW is on, @ is green if LDW is available to warn of a lane departure. If the vehicle crosses a detected lane marking without using the turn signal in that direction, @ changes to amber and flashes. Additionally, there will be three beeps on the right or left, depending on the lane departure direction. . . If the LDW system is not functioning properly when lane markings are clearly visible, cleaning the windshield may help. LDW alerts may occur due to tar marks, shadows, cracks in the road, temporary or construction lane markings, or other road imperfections. This is normal system operation; the vehicle does not need service. Turn LDW off if these conditions continue.