Method and device for adjusting lighting for a vehicle in consideration of the visibility of a curve, light having a glare effect being deactivated before negotiating a curve, if the curve is not visible, or optionally the illumination being increased if the curve is visible. These pedestals are of wood or other suitable thermal insulating and load bearing material fixed to the tank below its circumferential diameter along both the starboard and port tank sides. Subsequent to activation of Mg as an acceptor, the metal element is removed from the group III nitride semiconductor layer, and the concentration of the metal element is not more than 1100 of the concentration of Mg to realize a hole concentration of not less than 1018 to 1019 cm\u22123. The invention is useful in all hydrocarbon processing units, such as, refineries, distillation columns and other petrochemical industries.