What does it mean when the rear car flashes high and low beams alternately?

[DonovanLee]

The rear car flashing high and low beams alternately is a signal to the front car owner to indicate an intention to overtake, requesting the front car owner to pay attention and yield. Meaning of alternating high and low beams: Alternating between high and low beams is used for nighttime encounters with oncoming traffic, as an overtaking signal, or to switch between high and low beams to serve as a warning. Usage of alternating high and low beams: High beams should be turned on in poor lighting conditions, such as on highways or rural roads. In well-lit conditions, or when encountering oncoming traffic, following another vehicle, pedestrians, or non-motorized vehicles, switch to low beams. This is especially necessary on urban roads with streetlights. It is particularly important to flash the lights when overtaking large trucks, as they have large blind spots and high chassis. Repeated flashing is needed to alert the truck driver and ensure safety before overtaking.