“The signal means stop for the road user coming head on or from behind. The signal is used in a junction and applies as long as the officer is facing in the same direction. For road users approaching from the side, the signal means that the road is free and that it is permitted to drive. The signal may be given in combination with the signal P2, stop. The signal may be given using a stop paddle.” (Traffic Sign Ordinance)
The car shows your direction of travel.