After overtaking, the truck behind you flashes briefly once: this is what the driver wants to tell you
If you mean the common truck-driver/headlight signal after you overtake, a brief flash of the headlights often means: “You can move back into my lane.” The truck driver may be signaling that you’ve cleared the truck and can safely return in front of it. In some situations, it can simply mean “Thank you” or “I …









