What is an essential action before making a left turn?

Before making a left turn, it is crucial to look for pedestrians and cyclists. This action helps ensure the safety of all road users. Pedestrians may be crossing the street at intersections or may be present in crosswalks that drivers need to be aware of. Additionally, cyclists are often present in the vicinity of a vehicle, particularly when turning left, and they must be given the right of way if they are approaching or traveling in the same direction. This awareness is vital for preventing accidents and ensuring that the turn is made safely.

The other choices do not address the immediate need to be aware of vulnerable road users. Simply checking the rearview mirror does not provide comprehensive awareness of what might be approaching from the side or in crosswalks. Turning on hazard lights is typically reserved for situations where the vehicle is stopped or experiencing issues; it does not convey the intent to turn. Sounding the horn may alert others but should not be relied upon as a primary measure for ensuring safety while turning. Therefore, prioritizing the lookout for pedestrians and cyclists is essential for making a responsible and secure left turn.