After overtaking, the truck behind you flashes briefly once: this is what the driver wants to tell you.

each other short messages using their headlights and turn signals. A single short flash of light after an overtaking maneuver can be used to indicate that the overtaking vehicle has cleared the truck. Below, you can read what this signal may mean and why truck drivers sometimes use it.

Why Truck Drivers Do This

A truck with a semi-trailer can be well over sixteen meters long. Because the trailer extends a considerable distance behind the cab, it can be difficult for an overtaking driver to judge exactly when the entire