Thus, it is easier for the faster cars to lap the inferior cars. No matter what the car that see's the flag has to be aware a faster car is approaching to overtake him.The blue flags’ nature makes them prone to appear on the tracks which are shorter.

The panel can be operated manually by the Panel Marshal and then you will see a blue flag shown in the panel, or can be operated by Race Control and this will instead show the car's number that is going to be lapped also in blue.

Those, since 2018 are showing the car's to be lapped number in blue in the screen so the driver get to know easier it is him that will be lapped by the race leader). (and, or, in Formula 1 also there is the blue flag in the panels that F1 brings to every race and that are controlled by Race Direction. So when YY approaches that marshal post, the flag marshal has to wave the blue flag to it. A flag marshal is usually told by race direction via radio that the leader car is number XX and that number car YY is in front of him and will need to see blue flags. To explain more how do the blue flags go in the ground: If that does not happen, accidents like the one in Brazil 2018 when an unlapped car hit the race leader (Verstappen) might destroy race the leader's race and pace and concur in actions and sanctions by Race Direction to the unlapping car for creating an accident.

Of course that can happen, but the unlapping car has to be aware that its actions can concur on changing the race results and so has to be very cautious when trying to unlap and make it clear to the race leader. It is not normal that backmarkers try to unlap themselves because normally they do not have the speed.

Usually in a Formula 1 perspective, Blue Flags are waved to slower cars that are about to become lapped by the leader or someone else.

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