What does this sign mean?
En español: ¿Qué significa esta señal?
Why this is the correct answer
Indicates the start of a 2+1 road, that is, a road with three traffic lanes and two-way traffic. The centre lane is used to facilitate overtaking manoeuvres and is alternately reserved for one direction of traffic and the other. This sign may also indicate the branch of a junction leading to a 2+1 road.