What must you do if you intend to turn left at a traffic light?

When intending to turn left at a traffic light, it is essential to yield to oncoming traffic. This is because vehicles coming from the opposite direction may be moving straight through the intersection or turning right and can pose a hazard to your left turn. Yielding ensures that you do not cause a collision and that it is safe for you to make your turn.

The other options do not reflect safe driving practices. Simply signaling only if a vehicle is behind you is inadequate. You should always signal your intentions to turn, regardless of whether there are other vehicles nearby. Speeding up to get ahead carries the risk of not only endangering yourself but also other road users. Lastly, turning without looking is dangerous and irresponsible, as it disregards the need to assess the intersection for any potential hazards or obstructions.