You are driving on the highway and overtaking a large truck. As soon as you pass it, you suddenly see a brief flash of light in your mirror . You might immediately think the driver is angry. Or that you are driving too slowly and need to move to the right quickly. However, such a brief light signal after overtaking usually means something completely different. Often, the truck driver is actually trying to help you.
Truck drivers use various informal signals on the road. They can send each other short messages using their headlights and turn signals. A single short flash of light after an overtaking maneuver often has a very practical meaning. Below, you can read exactly what that signal entails and why truck drivers do this.
Why truck drivers do this
A truck with a semi-trailer can be well over sixteen meters long. This sometimes makes it difficult to see exactly where the rear of the truck ends from the cab. This plays an important role, especially during overtaking. Moreover, trucks often drive at approximately the same speed. As a result, the speed difference during an overtaking maneuver is sometimes only a few kilometers per hour. Consequently, a truck can drive alongside another truck for quite a long time.
The driver being overtaken often has a clear view of the end of the other combination. As soon as the entire semi-trailer has passed, he can briefly signal with his headlights. This indicates that there is sufficient room to move back to the right. Such a signal is therefore usually intended in a friendly manner. The truck driver is not trying to rush his colleague; he is simply helping him to better estimate the length of his vehicle.
