The driver of the red vehicle intends to go straight, but the auxiliary traffic light shows a green right-turn arrow while the main light is red. Should the driver allow the blue vehicle behind to pass if it intends to turn right?

Why this is the correct answer

The image shows a traffic light with a red main light and a green right-turn arrow (auxiliary light). Under Spanish traffic rules (Article 146.g of the General Traffic Regulations), a green arrow on a traffic light allows vehicles to turn in that direction regardless of the main light being red. Furthermore, any vehicle in a lane exclusively reserved for the direction indicated by the green arrow, or in the lane that traffic following the arrow must use, is obliged to proceed in that direction. There are two key scenarios: 1. If the lane has a single right-turn arrow painted on the pavement (mandatory right turn), all vehicles in that lane MUST follow the green arrow and turn right. The red car cannot simply wait for the main green light. In this case, it must turn right or move to another lane, so as not to block the blue car. 2. Even if the lane is shared (e.g., marked with both a straight and right-turn arrow), a vehicle that is blocking another vehicle behind it from following the lit green arrow is still required to proceed in the direction of the arrow. Option A is correct because it identifies the critical condition: when the right turn is mandatory for that lane, the red vehicle must yield to the blue vehicle by either turning right or changing lanes. Option B is incorrect because simply moving left is not required by the rule — the obligation is to follow the arrow direction when in a mandatory lane. Option C is wrong because, although the main light is red (prohibiting going straight), the green arrow specifically authorises the right turn, so the blue car has a legal right to proceed. Remember: always position yourself in the correct lane before reaching the intersection. If you intend to go straight, do not occupy a right-turn-only lane.