When two vehicles meet on a sharp curve...

Correct answer: the vehicle taking the curve to its right will be the first to switch from high beams to low beams.

On a sharp curve, the driver following the curve to the right is on the inside, and their headlights point toward the oncoming lane, so they switch to low beams first. The driver following the curve to the left is on the outside, and their beam points off the road. They switch too, but can do so later. In the image, the red vehicle is following the curve to the right.

Luces: cuáles son y cómo usarlas · Real Decreto 1428/2003, de 21 de noviembre, por el que se aprueba el Reglamento General de Circulación