What should you observe before trying to pass a tractor-trailer?

Observing the turn signals of a tractor-trailer is essential before attempting to pass it. Turn signals indicate the driver's intent to change lanes or make a turn. This information is crucial for your safety and the safety of the truck driver. If the tractor-trailer is signaling a lane change or a turn, passing at that moment could lead to a dangerous situation where you may not have the space to maneuver safely.

Assessing the situation based on the turn signals allows you to make informed decisions about when to safely pass, ensuring you are not interfering with the truck's movement. This vigilance is particularly important since tractor-trailers have larger blind spots and can take longer to stop than smaller vehicles, making understanding their signaling even more critical.

While other factors like the position of the driver in the cab, the weather conditions, and the headlights can provide context, they do not specifically indicate the current actions or intentions of the tractor-trailer as clearly as the turn signals do.